nix-find-roots: Cleanup

Based on an offline review by @mopleen (thanks!)

.github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature request
 about: Suggest an idea for this project
 title: ''
-labels: feature
+labels: improvement
 assignees: ''
 
 ---

.github/ISSUE_TEMPLATE/missing_documentation.md

@@ -1,28 +0,0 @@
----
-name: Missing or incorrect documentation
-about: Help us improve the reference manual
-title: ''
-labels: documentation
-assignees: ''
-
----
-
-## Problem
-
-<!-- describe your problem -->
-
-## Checklist
-
-<!-- make sure this issue is not redundant or obsolete -->
-
-- [ ] checked [latest Nix manual] \([source])
-- [ ] checked [open documentation issues and pull requests] for possible duplicates
-
-[latest Nix manual]: https://nixos.org/manual/nix/unstable/
-[source]: https://github.com/NixOS/nix/tree/master/doc/manual/src
-[open documentation issues and pull requests]: https://github.com/NixOS/nix/labels/documentation
-
-## Proposal
-
-<!-- propose a solution -->
-

.github/stale.yml

@@ -1,9 +1,10 @@
 # Configuration for probot-stale - https://github.com/probot/stale
 daysUntilStale: 180
-daysUntilClose: false
+daysUntilClose: 365
 exemptLabels:
   - "critical"
-  - "never-stale"
 staleLabel: "stale"
-markComment: false
-closeComment: false
+markComment: |
+  I marked this as stale due to inactivity. → [More info](https://github.com/NixOS/nix/blob/master/.github/STALE-BOT.md)
+closeComment: |
+  I closed this issue due to inactivity. → [More info](https://github.com/NixOS/nix/blob/master/.github/STALE-BOT.md)

.github/workflows/backport.yml

@@ -2,26 +2,20 @@ name: Backport
 on:
   pull_request_target:
     types: [closed, labeled]
-permissions:
-  contents: read
 jobs:
   backport:
     name: Backport Pull Request
-    permissions:
-      # for zeebe-io/backport-action
-      contents: write
-      pull-requests: write
     if: github.repository_owner == 'NixOS' && github.event.pull_request.merged == true && (github.event_name != 'labeled' || startsWith('backport', github.event.label.name))
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           # required to find all branches
           fetch-depth: 0
       - name: Create backport PRs
         # should be kept in sync with `version`
-        uses: zeebe-io/backport-action@v0.0.8
+        uses: zeebe-io/backport-action@v0.0.7
         with:
           # Config README: https://github.com/zeebe-io/backport-action#backport-action
           github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -4,61 +4,53 @@ on:
   pull_request:
   push:
 
-permissions: read-all
-
 jobs:
 
   tests:
-    needs: [check_secrets]
+    needs: [check_cachix]
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v2.4.0
       with:
         fetch-depth: 0
-    - uses: cachix/install-nix-action@v17
+    - uses: cachix/install-nix-action@v16
     - run: echo CACHIX_NAME="$(echo $GITHUB_REPOSITORY-install-tests | tr "[A-Z]/" "[a-z]-")" >> $GITHUB_ENV
     - uses: cachix/cachix-action@v10
-      if: needs.check_secrets.outputs.cachix == 'true'
+      if: needs.check_cachix.outputs.secret == 'true'
       with:
         name: '${{ env.CACHIX_NAME }}'
         signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
         authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
     - run: nix --experimental-features 'nix-command flakes' flake check -L
 
-  check_secrets:
-    permissions:
-      contents: none
-    name: Check Cachix and Docker secrets present for installer tests
+  check_cachix:
+    name: Cachix secret present for installer tests
     runs-on: ubuntu-latest
     outputs:
-      cachix: ${{ steps.secret.outputs.cachix }}
-      docker: ${{ steps.secret.outputs.docker }}
+      secret: ${{ steps.secret.outputs.secret }}
     steps:
-      - name: Check for secrets
+      - name: Check for Cachix secret
         id: secret
         env:
           _CACHIX_SECRETS: ${{ secrets.CACHIX_SIGNING_KEY }}${{ secrets.CACHIX_AUTH_TOKEN }}
-          _DOCKER_SECRETS: ${{ secrets.DOCKERHUB_USERNAME }}${{ secrets.DOCKERHUB_TOKEN }}
-        run: |
-          echo "::set-output name=cachix::${{ env._CACHIX_SECRETS != '' }}"
-          echo "::set-output name=docker::${{ env._DOCKER_SECRETS != '' }}"
+        run: echo "::set-output name=secret::${{ env._CACHIX_SECRETS != '' }}"
 
   installer:
-    needs: [tests, check_secrets]
-    if: github.event_name == 'push' && needs.check_secrets.outputs.cachix == 'true'
+    needs: [tests, check_cachix]
+    if: github.event_name == 'push' && needs.check_cachix.outputs.secret == 'true'
     runs-on: ubuntu-latest
     outputs:
       installerURL: ${{ steps.prepare-installer.outputs.installerURL }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v2.4.0
       with:
         fetch-depth: 0
     - run: echo CACHIX_NAME="$(echo $GITHUB_REPOSITORY-install-tests | tr "[A-Z]/" "[a-z]-")" >> $GITHUB_ENV
-    - uses: cachix/install-nix-action@v17
+    - uses: cachix/install-nix-action@v16
     - uses: cachix/cachix-action@v10
       with:
         name: '${{ env.CACHIX_NAME }}'
@@ -68,45 +60,37 @@ jobs:
       run: scripts/prepare-installer-for-github-actions
 
   installer_test:
-    needs: [installer, check_secrets]
-    if: github.event_name == 'push' && needs.check_secrets.outputs.cachix == 'true'
+    needs: [installer, check_cachix]
+    if: github.event_name == 'push' && needs.check_cachix.outputs.secret == 'true'
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v2.4.0
     - run: echo CACHIX_NAME="$(echo $GITHUB_REPOSITORY-install-tests | tr "[A-Z]/" "[a-z]-")" >> $GITHUB_ENV
-    - uses: cachix/install-nix-action@v17
+    - uses: cachix/install-nix-action@v16
       with:
         install_url: '${{needs.installer.outputs.installerURL}}'
         install_options: "--tarball-url-prefix https://${{ env.CACHIX_NAME }}.cachix.org/serve"
-    - run: sudo apt install fish zsh
-      if: matrix.os == 'ubuntu-latest'
-    - run: brew install fish
-      if: matrix.os == 'macos-latest'
-    - run: exec bash -c "nix-instantiate -E 'builtins.currentTime' --eval"
-    - run: exec sh -c "nix-instantiate -E 'builtins.currentTime' --eval"
-    - run: exec zsh -c "nix-instantiate -E 'builtins.currentTime' --eval"
-    - run: exec fish -c "nix-instantiate -E 'builtins.currentTime' --eval"
+    - run: nix-instantiate -E 'builtins.currentTime' --eval
 
   docker_push_image:
-    needs: [check_secrets, tests]
+    needs: [check_cachix, tests]
     if: >-
       github.event_name == 'push' &&
       github.ref_name == 'master' &&
-      needs.check_secrets.outputs.cachix == 'true' &&
-      needs.check_secrets.outputs.docker == 'true'
+      needs.check_cachix.outputs.secret == 'true'
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v2.4.0
       with:
         fetch-depth: 0
-    - uses: cachix/install-nix-action@v17
+    - uses: cachix/install-nix-action@v16
     - run: echo CACHIX_NAME="$(echo $GITHUB_REPOSITORY-install-tests | tr "[A-Z]/" "[a-z]-")" >> $GITHUB_ENV
-    - run: echo NIX_VERSION="$(nix --experimental-features 'nix-command flakes' eval .\#default.version | tr -d \")" >> $GITHUB_ENV
+    - run: echo NIX_VERSION="$(nix-instantiate --eval -E '(import ./default.nix).defaultPackage.${builtins.currentSystem}.version' | tr -d \")" >> $GITHUB_ENV
     - uses: cachix/cachix-action@v10
-      if: needs.check_secrets.outputs.cachix == 'true'
+      if: needs.check_cachix.outputs.secret == 'true'
       with:
         name: '${{ env.CACHIX_NAME }}'
         signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
@@ -116,7 +100,7 @@ jobs:
     - run: docker tag nix:$NIX_VERSION nixos/nix:$NIX_VERSION
     - run: docker tag nix:$NIX_VERSION nixos/nix:master
     - name: Login to Docker Hub
-      uses: docker/login-action@v2
+      uses: docker/login-action@v1
       with:
         username: ${{ secrets.DOCKERHUB_USERNAME }}
         password: ${{ secrets.DOCKERHUB_TOKEN }}

.github/workflows/hydra_status.yml

@@ -1,19 +1,15 @@
 name: Hydra status
-
-permissions: read-all
-
 on:
   schedule:
     - cron: "12,42 * * * *"
   workflow_dispatch:
-
 jobs:
   check_hydra_status:
     name: Check Hydra status
     if: github.repository_owner == 'NixOS'
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v2.4.0
       with:
         fetch-depth: 0
     - run: bash scripts/check-hydra-status.sh

.gitignore

@@ -22,13 +22,11 @@ perl/Makefile.config
 /doc/manual/src/SUMMARY.md
 /doc/manual/src/command-ref/new-cli
 /doc/manual/src/command-ref/conf-file.md
-/doc/manual/src/language/builtins.md
+/doc/manual/src/expressions/builtins.md
 
 # /scripts/
 /scripts/nix-profile.sh
 /scripts/nix-profile-daemon.sh
-/scripts/nix-profile.fish
-/scripts/nix-profile-daemon.fish
 
 # /src/libexpr/
 /src/libexpr/lexer-tab.cc
@@ -37,7 +35,6 @@ perl/Makefile.config
 /src/libexpr/parser-tab.hh
 /src/libexpr/parser-tab.output
 /src/libexpr/nix.tbl
-/src/libexpr/tests/libexpr-tests
 
 # /src/libstore/
 *.gen.*
@@ -82,7 +79,6 @@ perl/Makefile.config
 /tests/shell.drv
 /tests/config.nix
 /tests/ca/config.nix
-/tests/repl-result-out
 
 # /tests/lang/
 /tests/lang/*.out
@@ -94,7 +90,6 @@ perl/Makefile.config
 
 /misc/systemd/nix-daemon.service
 /misc/systemd/nix-daemon.socket
-/misc/systemd/nix-daemon.conf
 /misc/upstart/nix-daemon.conf
 
 /src/resolve-system-dependencies/resolve-system-dependencies

.version

@@ -1 +1 @@
-2.12.0
+2.7.0

Makefile

@@ -2,13 +2,13 @@ makefiles = \
   mk/precompiled-headers.mk \
   local.mk \
   src/libutil/local.mk \
+  src/nix-find-roots/local.mk \
   src/libutil/tests/local.mk \
   src/libstore/local.mk \
   src/libstore/tests/local.mk \
   src/libfetchers/local.mk \
   src/libmain/local.mk \
   src/libexpr/local.mk \
-  src/libexpr/tests/local.mk \
   src/libcmd/local.mk \
   src/nix/local.mk \
   src/resolve-system-dependencies/local.mk \
@@ -28,8 +28,7 @@ makefiles = \
 OPTIMIZE = 1
 
 ifeq ($(OPTIMIZE), 1)
-  GLOBAL_CXXFLAGS += -O3 $(CXXLTO)
-  GLOBAL_LDFLAGS += $(CXXLTO)
+  GLOBAL_CXXFLAGS += -O3
 else
   GLOBAL_CXXFLAGS += -O0 -U_FORTIFY_SOURCE
 endif

Makefile.config.in

@@ -1,3 +1,4 @@
+HOST_OS = @host_os@
 AR = @AR@
 BDW_GC_LIBS = @BDW_GC_LIBS@
 BOOST_LDFLAGS = @BOOST_LDFLAGS@
@@ -6,20 +7,18 @@ CC = @CC@
 CFLAGS = @CFLAGS@
 CXX = @CXX@
 CXXFLAGS = @CXXFLAGS@
-CXXLTO = @CXXLTO@
 EDITLINE_LIBS = @EDITLINE_LIBS@
 ENABLE_S3 = @ENABLE_S3@
 GTEST_LIBS = @GTEST_LIBS@
 HAVE_LIBCPUID = @HAVE_LIBCPUID@
 HAVE_SECCOMP = @HAVE_SECCOMP@
-HOST_OS = @host_os@
 LDFLAGS = @LDFLAGS@
 LIBARCHIVE_LIBS = @LIBARCHIVE_LIBS@
 LIBBROTLI_LIBS = @LIBBROTLI_LIBS@
 LIBCURL_LIBS = @LIBCURL_LIBS@
-LIBSECCOMP_LIBS = @LIBSECCOMP_LIBS@
 LOWDOWN_LIBS = @LOWDOWN_LIBS@
 OPENSSL_LIBS = @OPENSSL_LIBS@
+LIBSECCOMP_LIBS = @LIBSECCOMP_LIBS@
 PACKAGE_NAME = @PACKAGE_NAME@
 PACKAGE_VERSION = @PACKAGE_VERSION@
 SHELL = @bash@
@@ -31,7 +30,6 @@ datadir = @datadir@
 datarootdir = @datarootdir@
 doc_generate = @doc_generate@
 docdir = @docdir@
-embedded_sandbox_shell = @embedded_sandbox_shell@
 exec_prefix = @exec_prefix@
 includedir = @includedir@
 libdir = @libdir@

README.md

@@ -20,7 +20,7 @@ Information on additional installation methods is available on the [Nix download
 
 ## Building And Developing
 
-See our [Hacking guide](https://nixos.org/manual/nix/stable/contributing/hacking.html) in our manual for instruction on how to
+See our [Hacking guide](https://hydra.nixos.org/job/nix/master/build.x86_64-linux/latest/download-by-type/doc/manual/contributing/hacking.html) in our manual for instruction on how to
 build nix from source with nix-build or how to get a development environment.
 
 ## Additional Resources

boehmgc-coroutine-sp-fallback.diff

@@ -1,35 +1,3 @@
-diff --git a/darwin_stop_world.c b/darwin_stop_world.c
-index 3dbaa3fb..36a1d1f7 100644
---- a/darwin_stop_world.c
-+++ b/darwin_stop_world.c
-@@ -352,6 +352,7 @@ GC_INNER void GC_push_all_stacks(void)
-   int nthreads = 0;
-   word total_size = 0;
-   mach_msg_type_number_t listcount = (mach_msg_type_number_t)THREAD_TABLE_SZ;
-+  size_t stack_limit;
-   if (!EXPECT(GC_thr_initialized, TRUE))
-     GC_thr_init();
- 
-@@ -407,6 +408,19 @@ GC_INNER void GC_push_all_stacks(void)
-             GC_push_all_stack_sections(lo, hi, p->traced_stack_sect);
-           }
-           if (altstack_lo) {
-+            // When a thread goes into a coroutine, we lose its original sp until
-+            // control flow returns to the thread.
-+            // While in the coroutine, the sp points outside the thread stack,
-+            // so we can detect this and push the entire thread stack instead,
-+            // as an approximation.
-+            // We assume that the coroutine has similarly added its entire stack.
-+            // This could be made accurate by cooperating with the application
-+            // via new functions and/or callbacks.
-+            stack_limit = pthread_get_stacksize_np(p->id);
-+            if (altstack_lo >= altstack_hi || altstack_lo < altstack_hi - stack_limit) { // sp outside stack
-+              altstack_lo = altstack_hi - stack_limit;
-+            }
-+
-             total_size += altstack_hi - altstack_lo;
-             GC_push_all_stack(altstack_lo, altstack_hi);
-           }
 diff --git a/pthread_stop_world.c b/pthread_stop_world.c
 index 4b2c429..1fb4c52 100644
 --- a/pthread_stop_world.c

configure.ac

@@ -147,20 +147,6 @@ if test "x$GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC" = xyes; then
     LDFLAGS="-latomic $LDFLAGS"
 fi
 
-# LTO is currently broken with clang for unknown reasons; ld segfaults in the llvm plugin
-AC_ARG_ENABLE(lto, AS_HELP_STRING([--enable-lto],[Enable LTO (only supported with GCC) [default=no]]),
-  lto=$enableval, lto=no)
-if test "$lto" = yes; then
-    if $CXX --version | grep -q GCC; then
-        AC_SUBST(CXXLTO, [-flto=jobserver])
-    else
-        echo "error: LTO is only supported with GCC at the moment" >&2
-        exit 1
-    fi
-else
-    AC_SUBST(CXXLTO, [""])
-fi
-
 PKG_PROG_PKG_CONFIG
 
 AC_ARG_ENABLE(shared, AS_HELP_STRING([--enable-shared],[Build shared libraries for Nix [default=yes]]),
@@ -299,25 +285,6 @@ AC_CHECK_FUNCS([strsignal posix_fallocate sysconf])
 AC_ARG_WITH(sandbox-shell, AS_HELP_STRING([--with-sandbox-shell=PATH],[path of a statically-linked shell to use as /bin/sh in sandboxes]),
   sandbox_shell=$withval)
 AC_SUBST(sandbox_shell)
-if test ${cross_compiling:-no} = no && ! test -z ${sandbox_shell+x}; then
-  AC_MSG_CHECKING([whether sandbox-shell has the standalone feature])
-  # busybox shell sometimes allows executing other busybox applets,
-  # even if they are not in the path, breaking our sandbox
-  if PATH= $sandbox_shell -c "busybox" 2>&1 | grep -qv "not found"; then
-    AC_MSG_RESULT(enabled)
-    AC_MSG_ERROR([Please disable busybox FEATURE_SH_STANDALONE])
-  else
-    AC_MSG_RESULT(disabled)
-  fi
-fi
-
-AC_ARG_ENABLE(embedded-sandbox-shell, AS_HELP_STRING([--enable-embedded-sandbox-shell],[include the sandbox shell in the Nix binary [default=no]]),
-  embedded_sandbox_shell=$enableval, embedded_sandbox_shell=no)
-AC_SUBST(embedded_sandbox_shell)
-if test "$embedded_sandbox_shell" = yes; then
-  AC_DEFINE(HAVE_EMBEDDED_SANDBOX_SHELL, 1, [Include the sandbox shell in the Nix binary.])
-fi
-
 
 # Expand all variables in config.status.
 test "$prefix" = NONE && prefix=$ac_default_prefix

doc/manual/anchors.jq

@@ -1,31 +0,0 @@
-"\\[\\]\\{#(?<anchor>[^\\}]+?)\\}" as $empty_anchor_regex |
-"\\[(?<text>[^\\]]+?)\\]\\{#(?<anchor>[^\\}]+?)\\}" as $anchor_regex |
-
-
-def transform_anchors_html:
-    . | gsub($empty_anchor_regex; "<a name=\"" + .anchor + "\"></a>")
-      | gsub($anchor_regex; "<a href=\"#" + .anchor + "\" id=\"" + .anchor + "\">" + .text + "</a>");
-
-
-def transform_anchors_strip:
-    . | gsub($empty_anchor_regex; "")
-      | gsub($anchor_regex; .text);
-
-
-def map_contents_recursively(transformer):
-    . + {
-        Chapter: (.Chapter + {
-            content: .Chapter.content | transformer,
-            sub_items: .Chapter.sub_items | map(map_contents_recursively(transformer)),
-        }),
-    };
-
-
-def process_command:
-    .[0] as $context |
-    .[1] as $body |
-    $body + {
-        sections: $body.sections | map(map_contents_recursively(if $context.renderer == "html" then transform_anchors_html else transform_anchors_strip end)),
-    };
-
-process_command

doc/manual/book.toml

@@ -1,7 +1,2 @@
 [output.html]
 additional-css = ["custom.css"]
-additional-js = ["redirects.js"]
-
-[preprocessor.anchors]
-renderers = ["html"]
-command = "jq --from-file doc/manual/anchors.jq"

doc/manual/generate-manpage.nix

@@ -1,110 +1,99 @@
-{ command }:
+{ command, renderLinks ? false }:
 
 with builtins;
 with import ./utils.nix;
 
 let
 
-  showCommand = { command, details, filename }:
-    let
-      result = ''
-        > **Warning** \
-        > This program is **experimental** and its interface is subject to change.
-
-        # Name
-
-        `${command}` - ${details.description}
-
-        # Synopsis
-
-        ${showSynopsis command details.args}
-
-        ${maybeSubcommands}
-
-        ${maybeDocumentation}
-
-        ${maybeOptions}
-      '';
-      showSynopsis = command: args:
-        let
-          showArgument = arg: "*${arg.label}*" + (if arg ? arity then "" else "...");
-          arguments = concatStringsSep " " (map showArgument args);
-        in ''
-         `${command}` [*option*...] ${arguments}
-        '';
-      maybeSubcommands = if details ? commands && details.commands != {}
-        then ''
-           where *subcommand* is one of the following:
-
-           ${subcommands}
-         ''
-        else "";
-      subcommands = if length categories > 1
-        then listCategories
-        else listSubcommands details.commands;
-      categories = sort (x: y: x.id < y.id) (unique (map (cmd: cmd.category) (attrValues details.commands)));
-      listCategories = concatStrings (map showCategory categories);
-      showCategory = cat: ''
-        **${toString cat.description}:**
-
-        ${listSubcommands (filterAttrs (n: v: v.category == cat) details.commands)}
-      '';
-      listSubcommands = cmds: concatStrings (attrValues (mapAttrs showSubcommand cmds));
-      showSubcommand = name: subcmd: ''
-        * [`${command} ${name}`](./${appendName filename name}.md) - ${subcmd.description}
-      '';
-      maybeDocumentation = if details ? doc then details.doc else "";
-      maybeOptions = if details.flags == {} then "" else ''
-        # Options
-
-        ${showOptions details.flags}
-      '';
-      showOptions = options:
-        let
-          showCategory = cat: ''
-            ${if cat != "" then "**${cat}:**" else ""}
-
-            ${listOptions (filterAttrs (n: v: v.category == cat) options)}
-            '';
-          listOptions = opts: concatStringsSep "\n" (attrValues (mapAttrs showOption opts));
-          showOption = name: option:
-            let
-              shortName = if option ? shortName then "/ `-${option.shortName}`" else "";
-              labels = if option ? labels then (concatStringsSep " " (map (s: "*${s}*") option.labels)) else "";
-            in trim ''
-              - `--${name}` ${shortName} ${labels}
-
-                ${option.description}
-            '';
-          categories = sort builtins.lessThan (unique (map (cmd: cmd.category) (attrValues options)));
-        in concatStrings (map showCategory categories);
-    in squash result;
+  showCommand =
+    { command, def, filename }:
+    ''
+      **Warning**: This program is **experimental** and its interface is subject to change.
+    ''
+    + "# Name\n\n"
+    + "`${command}` - ${def.description}\n\n"
+    + "# Synopsis\n\n"
+    + showSynopsis { inherit command; args = def.args; }
+    + (if def.commands or {} != {}
+       then
+         let
+           categories = sort (x: y: x.id < y.id) (unique (map (cmd: cmd.category) (attrValues def.commands)));
+           listCommands = cmds:
+             concatStrings (map (name:
+               "* "
+               + (if renderLinks
+                  then "[`${command} ${name}`](./${appendName filename name}.md)"
+                  else "`${command} ${name}`")
+               + " - ${cmds.${name}.description}\n")
+               (attrNames cmds));
+         in
+         "where *subcommand* is one of the following:\n\n"
+         # FIXME: group by category
+         + (if length categories > 1
+            then
+              concatStrings (map
+                (cat:
+                  "**${toString cat.description}:**\n\n"
+                  + listCommands (filterAttrs (n: v: v.category == cat) def.commands)
+                  + "\n"
+                ) categories)
+              + "\n"
+            else
+              listCommands def.commands
+              + "\n")
+       else "")
+    + (if def ? doc
+       then def.doc + "\n\n"
+       else "")
+    + (let s = showOptions def.flags; in
+       if s != ""
+       then "# Options\n\n${s}"
+       else "")
+  ;
 
   appendName = filename: name: (if filename == "nix" then "nix3" else filename) + "-" + name;
 
-  processCommand = { command, details, filename }:
+  showOptions = flags:
     let
-      cmd = {
-        inherit command;
-        name = filename + ".md";
-        value = showCommand { inherit command details filename; };
-      };
-      subcommand = subCmd: processCommand {
-        command = command + " " + subCmd;
-        details = details.commands.${subCmd};
-        filename = appendName filename subCmd;
-      };
-    in [ cmd ] ++ concatMap subcommand (attrNames details.commands or {});
+      categories = sort builtins.lessThan (unique (map (cmd: cmd.category) (attrValues flags)));
+    in
+      concatStrings (map
+        (cat:
+          (if cat != ""
+           then "**${cat}:**\n\n"
+           else "")
+          + concatStrings
+            (map (longName:
+              let
+                flag = flags.${longName};
+              in
+                "  - `--${longName}`"
+                + (if flag ? shortName then " / `-${flag.shortName}`" else "")
+                + (if flag ? labels then " " + (concatStringsSep " " (map (s: "*${s}*") flag.labels)) else "")
+                + "  \n"
+                + "    " + flag.description + "\n\n"
+            ) (attrNames (filterAttrs (n: v: v.category == cat) flags))))
+        categories);
 
-  manpages = processCommand {
-    command = "nix";
-    details = builtins.fromJSON command;
-    filename = "nix";
-  };
+  showSynopsis =
+    { command, args }:
+    "`${command}` [*option*...] ${concatStringsSep " "
+      (map (arg: "*${arg.label}*" + (if arg ? arity then "" else "...")) args)}\n\n";
 
-  tableOfContents = let
-    showEntry = page:
-      "    - [${page.command}](command-ref/new-cli/${page.name})";
-    in concatStringsSep "\n" (map showEntry manpages) + "\n";
+  processCommand = { command, def, filename }:
+    [ { name = filename + ".md"; value = showCommand { inherit command def filename; }; inherit command; } ]
+    ++ concatMap
+      (name: processCommand {
+        filename = appendName filename name;
+        command = command + " " + name;
+        def = def.commands.${name};
+      })
+      (attrNames def.commands or {});
 
-in (listToAttrs manpages) // { "SUMMARY.md" = tableOfContents; }
+in
+
+let
+  manpages = processCommand { filename = "nix"; command = "nix"; def = builtins.fromJSON command; };
+  summary = concatStrings (map (manpage: "    - [${manpage.command}](command-ref/new-cli/${manpage.name})\n") manpages);
+in
+(listToAttrs manpages) // { "SUMMARY.md" = summary; }

doc/manual/generate-options.nix

@@ -6,8 +6,7 @@ options:
 concatStrings (map
   (name:
     let option = options.${name}; in
-    "  - [`${name}`](#conf-${name})"
-    + "<p id=\"conf-${name}\"></p>\n\n"
+    "  - `${name}`  \n\n"
     + concatStrings (map (s: "    ${s}\n") (splitLines option.description)) + "\n\n"
     + (if option.documentDefault
        then "    **Default:** " + (

doc/manual/local.mk

@@ -1,9 +1,5 @@
 ifeq ($(doc_generate),yes)
 
-MANUAL_SRCS := \
-  $(call rwildcard, $(d)/src, *.md) \
-  $(call rwildcard, $(d)/src, */*.md)
-
 # Generate man pages.
 man-pages := $(foreach n, \
   nix-env.1 nix-build.1 nix-shell.1 nix-store.1 nix-instantiate.1 \
@@ -50,7 +46,7 @@ $(d)/src/SUMMARY.md: $(d)/src/SUMMARY.md.in $(d)/src/command-ref/new-cli
 
 $(d)/src/command-ref/new-cli: $(d)/nix.json $(d)/generate-manpage.nix $(bindir)/nix
 	@rm -rf $@
-	$(trace-gen) $(nix-eval) --write-to $@ --expr 'import doc/manual/generate-manpage.nix { command = builtins.readFile $<; }'
+	$(trace-gen) $(nix-eval) --write-to $@ --expr 'import doc/manual/generate-manpage.nix { command = builtins.readFile $<; renderLinks = true; }'
 
 $(d)/src/command-ref/conf-file.md: $(d)/conf-file.json $(d)/generate-options.nix $(d)/src/command-ref/conf-file-prefix.md $(bindir)/nix
 	@cat doc/manual/src/command-ref/conf-file-prefix.md > $@.tmp
@@ -65,10 +61,10 @@ $(d)/conf-file.json: $(bindir)/nix
 	$(trace-gen) $(dummy-env) $(bindir)/nix show-config --json --experimental-features nix-command > $@.tmp
 	@mv $@.tmp $@
 
-$(d)/src/language/builtins.md: $(d)/builtins.json $(d)/generate-builtins.nix $(d)/src/language/builtins-prefix.md $(bindir)/nix
-	@cat doc/manual/src/language/builtins-prefix.md > $@.tmp
+$(d)/src/expressions/builtins.md: $(d)/builtins.json $(d)/generate-builtins.nix $(d)/src/expressions/builtins-prefix.md $(bindir)/nix
+	@cat doc/manual/src/expressions/builtins-prefix.md > $@.tmp
 	$(trace-gen) $(nix-eval) --expr 'import doc/manual/generate-builtins.nix (builtins.fromJSON (builtins.readFile $<))' >> $@.tmp
-	@cat doc/manual/src/language/builtins-suffix.md >> $@.tmp
+	@cat doc/manual/src/expressions/builtins-suffix.md >> $@.tmp
 	@mv $@.tmp $@
 
 $(d)/builtins.json: $(bindir)/nix
@@ -96,12 +92,12 @@ doc/manual/generated/man1/nix3-manpages: $(d)/src/command-ref/new-cli
 	  if [[ $$name = SUMMARY ]]; then continue; fi; \
 	  printf "Title: %s\n\n" "$$name" > $$tmpFile; \
 	  cat $$i >> $$tmpFile; \
-	  lowdown -sT man --nroff-nolinks -M section=1 $$tmpFile -o $(DESTDIR)$$(dirname $@)/$$name.1; \
+	  lowdown -sT man -M section=1 $$tmpFile -o $(DESTDIR)$$(dirname $@)/$$name.1; \
 	  rm $$tmpFile; \
 	done
 	@touch $@
 
-$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/anchors.jq $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/command-ref/conf-file.md $(d)/src/language/builtins.md
+$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/command-ref/conf-file.md $(d)/src/expressions/builtins.md $(call rwildcard, $(d)/src, *.md)
 	$(trace-gen) RUST_LOG=warn mdbook build doc/manual -d $(DESTDIR)$(docdir)/manual
 
 endif

doc/manual/redirects.js

@@ -1,330 +0,0 @@
-// Redirects from old DocBook manual.
-var redirects = {
-  "#part-advanced-topics": "advanced-topics/advanced-topics.html",
-  "#chap-tuning-cores-and-jobs": "advanced-topics/cores-vs-jobs.html",
-  "#chap-diff-hook": "advanced-topics/diff-hook.html",
-  "#check-dirs-are-unregistered": "advanced-topics/diff-hook.html#check-dirs-are-unregistered",
-  "#chap-distributed-builds": "advanced-topics/distributed-builds.html",
-  "#chap-post-build-hook": "advanced-topics/post-build-hook.html",
-  "#chap-post-build-hook-caveats": "advanced-topics/post-build-hook.html#implementation-caveats",
-  "#part-command-ref": "command-ref/command-ref.html",
-  "#conf-allow-import-from-derivation": "command-ref/conf-file.html#conf-allow-import-from-derivation",
-  "#conf-allow-new-privileges": "command-ref/conf-file.html#conf-allow-new-privileges",
-  "#conf-allowed-uris": "command-ref/conf-file.html#conf-allowed-uris",
-  "#conf-allowed-users": "command-ref/conf-file.html#conf-allowed-users",
-  "#conf-auto-optimise-store": "command-ref/conf-file.html#conf-auto-optimise-store",
-  "#conf-binary-cache-public-keys": "command-ref/conf-file.html#conf-binary-cache-public-keys",
-  "#conf-binary-caches": "command-ref/conf-file.html#conf-binary-caches",
-  "#conf-build-compress-log": "command-ref/conf-file.html#conf-build-compress-log",
-  "#conf-build-cores": "command-ref/conf-file.html#conf-build-cores",
-  "#conf-build-extra-chroot-dirs": "command-ref/conf-file.html#conf-build-extra-chroot-dirs",
-  "#conf-build-extra-sandbox-paths": "command-ref/conf-file.html#conf-build-extra-sandbox-paths",
-  "#conf-build-fallback": "command-ref/conf-file.html#conf-build-fallback",
-  "#conf-build-max-jobs": "command-ref/conf-file.html#conf-build-max-jobs",
-  "#conf-build-max-log-size": "command-ref/conf-file.html#conf-build-max-log-size",
-  "#conf-build-max-silent-time": "command-ref/conf-file.html#conf-build-max-silent-time",
-  "#conf-build-repeat": "command-ref/conf-file.html#conf-build-repeat",
-  "#conf-build-timeout": "command-ref/conf-file.html#conf-build-timeout",
-  "#conf-build-use-chroot": "command-ref/conf-file.html#conf-build-use-chroot",
-  "#conf-build-use-sandbox": "command-ref/conf-file.html#conf-build-use-sandbox",
-  "#conf-build-use-substitutes": "command-ref/conf-file.html#conf-build-use-substitutes",
-  "#conf-build-users-group": "command-ref/conf-file.html#conf-build-users-group",
-  "#conf-builders": "command-ref/conf-file.html#conf-builders",
-  "#conf-builders-use-substitutes": "command-ref/conf-file.html#conf-builders-use-substitutes",
-  "#conf-compress-build-log": "command-ref/conf-file.html#conf-compress-build-log",
-  "#conf-connect-timeout": "command-ref/conf-file.html#conf-connect-timeout",
-  "#conf-cores": "command-ref/conf-file.html#conf-cores",
-  "#conf-diff-hook": "command-ref/conf-file.html#conf-diff-hook",
-  "#conf-enforce-determinism": "command-ref/conf-file.html#conf-enforce-determinism",
-  "#conf-env-keep-derivations": "command-ref/conf-file.html#conf-env-keep-derivations",
-  "#conf-extra-binary-caches": "command-ref/conf-file.html#conf-extra-binary-caches",
-  "#conf-extra-platforms": "command-ref/conf-file.html#conf-extra-platforms",
-  "#conf-extra-sandbox-paths": "command-ref/conf-file.html#conf-extra-sandbox-paths",
-  "#conf-extra-substituters": "command-ref/conf-file.html#conf-extra-substituters",
-  "#conf-fallback": "command-ref/conf-file.html#conf-fallback",
-  "#conf-fsync-metadata": "command-ref/conf-file.html#conf-fsync-metadata",
-  "#conf-gc-keep-derivations": "command-ref/conf-file.html#conf-gc-keep-derivations",
-  "#conf-gc-keep-outputs": "command-ref/conf-file.html#conf-gc-keep-outputs",
-  "#conf-hashed-mirrors": "command-ref/conf-file.html#conf-hashed-mirrors",
-  "#conf-http-connections": "command-ref/conf-file.html#conf-http-connections",
-  "#conf-keep-build-log": "command-ref/conf-file.html#conf-keep-build-log",
-  "#conf-keep-derivations": "command-ref/conf-file.html#conf-keep-derivations",
-  "#conf-keep-env-derivations": "command-ref/conf-file.html#conf-keep-env-derivations",
-  "#conf-keep-outputs": "command-ref/conf-file.html#conf-keep-outputs",
-  "#conf-max-build-log-size": "command-ref/conf-file.html#conf-max-build-log-size",
-  "#conf-max-free": "command-ref/conf-file.html#conf-max-free",
-  "#conf-max-jobs": "command-ref/conf-file.html#conf-max-jobs",
-  "#conf-max-silent-time": "command-ref/conf-file.html#conf-max-silent-time",
-  "#conf-min-free": "command-ref/conf-file.html#conf-min-free",
-  "#conf-narinfo-cache-negative-ttl": "command-ref/conf-file.html#conf-narinfo-cache-negative-ttl",
-  "#conf-narinfo-cache-positive-ttl": "command-ref/conf-file.html#conf-narinfo-cache-positive-ttl",
-  "#conf-netrc-file": "command-ref/conf-file.html#conf-netrc-file",
-  "#conf-plugin-files": "command-ref/conf-file.html#conf-plugin-files",
-  "#conf-post-build-hook": "command-ref/conf-file.html#conf-post-build-hook",
-  "#conf-pre-build-hook": "command-ref/conf-file.html#conf-pre-build-hook",
-  "#conf-repeat": "command-ref/conf-file.html#conf-repeat",
-  "#conf-require-sigs": "command-ref/conf-file.html#conf-require-sigs",
-  "#conf-restrict-eval": "command-ref/conf-file.html#conf-restrict-eval",
-  "#conf-run-diff-hook": "command-ref/conf-file.html#conf-run-diff-hook",
-  "#conf-sandbox": "command-ref/conf-file.html#conf-sandbox",
-  "#conf-sandbox-dev-shm-size": "command-ref/conf-file.html#conf-sandbox-dev-shm-size",
-  "#conf-sandbox-paths": "command-ref/conf-file.html#conf-sandbox-paths",
-  "#conf-secret-key-files": "command-ref/conf-file.html#conf-secret-key-files",
-  "#conf-show-trace": "command-ref/conf-file.html#conf-show-trace",
-  "#conf-stalled-download-timeout": "command-ref/conf-file.html#conf-stalled-download-timeout",
-  "#conf-substitute": "command-ref/conf-file.html#conf-substitute",
-  "#conf-substituters": "command-ref/conf-file.html#conf-substituters",
-  "#conf-system": "command-ref/conf-file.html#conf-system",
-  "#conf-system-features": "command-ref/conf-file.html#conf-system-features",
-  "#conf-tarball-ttl": "command-ref/conf-file.html#conf-tarball-ttl",
-  "#conf-timeout": "command-ref/conf-file.html#conf-timeout",
-  "#conf-trace-function-calls": "command-ref/conf-file.html#conf-trace-function-calls",
-  "#conf-trusted-binary-caches": "command-ref/conf-file.html#conf-trusted-binary-caches",
-  "#conf-trusted-public-keys": "command-ref/conf-file.html#conf-trusted-public-keys",
-  "#conf-trusted-substituters": "command-ref/conf-file.html#conf-trusted-substituters",
-  "#conf-trusted-users": "command-ref/conf-file.html#conf-trusted-users",
-  "#extra-sandbox-paths": "command-ref/conf-file.html#extra-sandbox-paths",
-  "#sec-conf-file": "command-ref/conf-file.html",
-  "#env-NIX_PATH": "command-ref/env-common.html#env-NIX_PATH",
-  "#env-common": "command-ref/env-common.html",
-  "#envar-remote": "command-ref/env-common.html#env-NIX_REMOTE",
-  "#sec-common-env": "command-ref/env-common.html",
-  "#ch-files": "command-ref/files.html",
-  "#ch-main-commands": "command-ref/main-commands.html",
-  "#opt-out-link": "command-ref/nix-build.html#opt-out-link",
-  "#sec-nix-build": "command-ref/nix-build.html",
-  "#sec-nix-channel": "command-ref/nix-channel.html",
-  "#sec-nix-collect-garbage": "command-ref/nix-collect-garbage.html",
-  "#sec-nix-copy-closure": "command-ref/nix-copy-closure.html",
-  "#sec-nix-daemon": "command-ref/nix-daemon.html",
-  "#refsec-nix-env-install-examples": "command-ref/nix-env.html#examples",
-  "#rsec-nix-env-install": "command-ref/nix-env.html#operation---install",
-  "#rsec-nix-env-set": "command-ref/nix-env.html#operation---set",
-  "#rsec-nix-env-set-flag": "command-ref/nix-env.html#operation---set-flag",
-  "#rsec-nix-env-upgrade": "command-ref/nix-env.html#operation---upgrade",
-  "#sec-nix-env": "command-ref/nix-env.html",
-  "#ssec-version-comparisons": "command-ref/nix-env.html#versions",
-  "#sec-nix-hash": "command-ref/nix-hash.html",
-  "#sec-nix-instantiate": "command-ref/nix-instantiate.html",
-  "#sec-nix-prefetch-url": "command-ref/nix-prefetch-url.html",
-  "#sec-nix-shell": "command-ref/nix-shell.html",
-  "#ssec-nix-shell-shebang": "command-ref/nix-shell.html#use-as-a--interpreter",
-  "#nixref-queries": "command-ref/nix-store.html#queries",
-  "#opt-add-root": "command-ref/nix-store.html#opt-add-root",
-  "#refsec-nix-store-dump": "command-ref/nix-store.html#operation---dump",
-  "#refsec-nix-store-export": "command-ref/nix-store.html#operation---export",
-  "#refsec-nix-store-import": "command-ref/nix-store.html#operation---import",
-  "#refsec-nix-store-query": "command-ref/nix-store.html#operation---query",
-  "#refsec-nix-store-verify": "command-ref/nix-store.html#operation---verify",
-  "#rsec-nix-store-gc": "command-ref/nix-store.html#operation---gc",
-  "#rsec-nix-store-generate-binary-cache-key": "command-ref/nix-store.html#operation---generate-binary-cache-key",
-  "#rsec-nix-store-realise": "command-ref/nix-store.html#operation---realise",
-  "#rsec-nix-store-serve": "command-ref/nix-store.html#operation---serve",
-  "#sec-nix-store": "command-ref/nix-store.html",
-  "#opt-I": "command-ref/opt-common.html#opt-I",
-  "#opt-attr": "command-ref/opt-common.html#opt-attr",
-  "#opt-common": "command-ref/opt-common.html",
-  "#opt-cores": "command-ref/opt-common.html#opt-cores",
-  "#opt-log-format": "command-ref/opt-common.html#opt-log-format",
-  "#opt-max-jobs": "command-ref/opt-common.html#opt-max-jobs",
-  "#opt-max-silent-time": "command-ref/opt-common.html#opt-max-silent-time",
-  "#opt-timeout": "command-ref/opt-common.html#opt-timeout",
-  "#sec-common-options": "command-ref/opt-common.html",
-  "#ch-utilities": "command-ref/utilities.html",
-  "#chap-hacking": "contributing/hacking.html",
-  "#adv-attr-allowSubstitutes": "language/advanced-attributes.html#adv-attr-allowSubstitutes",
-  "#adv-attr-allowedReferences": "language/advanced-attributes.html#adv-attr-allowedReferences",
-  "#adv-attr-allowedRequisites": "language/advanced-attributes.html#adv-attr-allowedRequisites",
-  "#adv-attr-disallowedReferences": "language/advanced-attributes.html#adv-attr-disallowedReferences",
-  "#adv-attr-disallowedRequisites": "language/advanced-attributes.html#adv-attr-disallowedRequisites",
-  "#adv-attr-exportReferencesGraph": "language/advanced-attributes.html#adv-attr-exportReferencesGraph",
-  "#adv-attr-impureEnvVars": "language/advanced-attributes.html#adv-attr-impureEnvVars",
-  "#adv-attr-outputHash": "language/advanced-attributes.html#adv-attr-outputHash",
-  "#adv-attr-outputHashAlgo": "language/advanced-attributes.html#adv-attr-outputHashAlgo",
-  "#adv-attr-outputHashMode": "language/advanced-attributes.html#adv-attr-outputHashMode",
-  "#adv-attr-passAsFile": "language/advanced-attributes.html#adv-attr-passAsFile",
-  "#adv-attr-preferLocalBuild": "language/advanced-attributes.html#adv-attr-preferLocalBuild",
-  "#fixed-output-drvs": "language/advanced-attributes.html#adv-attr-outputHash",
-  "#sec-advanced-attributes": "language/advanced-attributes.html",
-  "#builtin-abort": "language/builtins.html#builtins-abort",
-  "#builtin-add": "language/builtins.html#builtins-add",
-  "#builtin-all": "language/builtins.html#builtins-all",
-  "#builtin-any": "language/builtins.html#builtins-any",
-  "#builtin-attrNames": "language/builtins.html#builtins-attrNames",
-  "#builtin-attrValues": "language/builtins.html#builtins-attrValues",
-  "#builtin-baseNameOf": "language/builtins.html#builtins-baseNameOf",
-  "#builtin-bitAnd": "language/builtins.html#builtins-bitAnd",
-  "#builtin-bitOr": "language/builtins.html#builtins-bitOr",
-  "#builtin-bitXor": "language/builtins.html#builtins-bitXor",
-  "#builtin-builtins": "language/builtins.html#builtins-builtins",
-  "#builtin-compareVersions": "language/builtins.html#builtins-compareVersions",
-  "#builtin-concatLists": "language/builtins.html#builtins-concatLists",
-  "#builtin-concatStringsSep": "language/builtins.html#builtins-concatStringsSep",
-  "#builtin-currentSystem": "language/builtins.html#builtins-currentSystem",
-  "#builtin-deepSeq": "language/builtins.html#builtins-deepSeq",
-  "#builtin-derivation": "language/builtins.html#builtins-derivation",
-  "#builtin-dirOf": "language/builtins.html#builtins-dirOf",
-  "#builtin-div": "language/builtins.html#builtins-div",
-  "#builtin-elem": "language/builtins.html#builtins-elem",
-  "#builtin-elemAt": "language/builtins.html#builtins-elemAt",
-  "#builtin-fetchGit": "language/builtins.html#builtins-fetchGit",
-  "#builtin-fetchTarball": "language/builtins.html#builtins-fetchTarball",
-  "#builtin-fetchurl": "language/builtins.html#builtins-fetchurl",
-  "#builtin-filterSource": "language/builtins.html#builtins-filterSource",
-  "#builtin-foldl-prime": "language/builtins.html#builtins-foldl-prime",
-  "#builtin-fromJSON": "language/builtins.html#builtins-fromJSON",
-  "#builtin-functionArgs": "language/builtins.html#builtins-functionArgs",
-  "#builtin-genList": "language/builtins.html#builtins-genList",
-  "#builtin-getAttr": "language/builtins.html#builtins-getAttr",
-  "#builtin-getEnv": "language/builtins.html#builtins-getEnv",
-  "#builtin-hasAttr": "language/builtins.html#builtins-hasAttr",
-  "#builtin-hashFile": "language/builtins.html#builtins-hashFile",
-  "#builtin-hashString": "language/builtins.html#builtins-hashString",
-  "#builtin-head": "language/builtins.html#builtins-head",
-  "#builtin-import": "language/builtins.html#builtins-import",
-  "#builtin-intersectAttrs": "language/builtins.html#builtins-intersectAttrs",
-  "#builtin-isAttrs": "language/builtins.html#builtins-isAttrs",
-  "#builtin-isBool": "language/builtins.html#builtins-isBool",
-  "#builtin-isFloat": "language/builtins.html#builtins-isFloat",
-  "#builtin-isFunction": "language/builtins.html#builtins-isFunction",
-  "#builtin-isInt": "language/builtins.html#builtins-isInt",
-  "#builtin-isList": "language/builtins.html#builtins-isList",
-  "#builtin-isNull": "language/builtins.html#builtins-isNull",
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-  "#builtin-length": "language/builtins.html#builtins-length",
-  "#builtin-lessThan": "language/builtins.html#builtins-lessThan",
-  "#builtin-listToAttrs": "language/builtins.html#builtins-listToAttrs",
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-  "#builtin-match": "language/builtins.html#builtins-match",
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-  "#builtin-parseDrvName": "language/builtins.html#builtins-parseDrvName",
-  "#builtin-path": "language/builtins.html#builtins-path",
-  "#builtin-pathExists": "language/builtins.html#builtins-pathExists",
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-}

doc/manual/src/SUMMARY.md.in

@@ -26,14 +26,21 @@
     - [Copying Closures via SSH](package-management/copy-closure.md)
     - [Serving a Nix store via SSH](package-management/ssh-substituter.md)
     - [Serving a Nix store via S3](package-management/s3-substituter.md)
-- [Nix Language](language/index.md)
-  - [Data Types](language/values.md)
-  - [Language Constructs](language/constructs.md)
-  - [Operators](language/operators.md)
-  - [Derivations](language/derivations.md)
-    - [Advanced Attributes](language/advanced-attributes.md)
-  - [Built-in Constants](language/builtin-constants.md)
-  - [Built-in Functions](language/builtins.md)
+- [Writing Nix Expressions](expressions/writing-nix-expressions.md)
+  - [A Simple Nix Expression](expressions/simple-expression.md)
+    - [Expression Syntax](expressions/expression-syntax.md)
+    - [Build Script](expressions/build-script.md)
+    - [Arguments and Variables](expressions/arguments-variables.md)
+    - [Building and Testing](expressions/simple-building-testing.md)
+    - [Generic Builder Syntax](expressions/generic-builder.md)
+  - [Writing Nix Expressions](expressions/expression-language.md)
+    - [Values](expressions/language-values.md)
+    - [Language Constructs](expressions/language-constructs.md)
+    - [Operators](expressions/language-operators.md)
+    - [Derivations](expressions/derivations.md)
+      - [Advanced Attributes](expressions/advanced-attributes.md)
+    - [Built-in Constants](expressions/builtin-constants.md)
+    - [Built-in Functions](expressions/builtins.md)
 - [Advanced Topics](advanced-topics/advanced-topics.md)
   - [Remote Builds](advanced-topics/distributed-builds.md)
   - [Tuning Cores and Jobs](advanced-topics/cores-vs-jobs.md)
@@ -64,11 +71,6 @@
   - [Hacking](contributing/hacking.md)
   - [CLI guideline](contributing/cli-guideline.md)
 - [Release Notes](release-notes/release-notes.md)
-  - [Release X.Y (202?-??-??)](release-notes/rl-next.md)
-  - [Release 2.11 (2022-08-25)](release-notes/rl-2.11.md)
-  - [Release 2.10 (2022-07-11)](release-notes/rl-2.10.md)
-  - [Release 2.9 (2022-05-30)](release-notes/rl-2.9.md)
-  - [Release 2.8 (2022-04-19)](release-notes/rl-2.8.md)
   - [Release 2.7 (2022-03-07)](release-notes/rl-2.7.md)
   - [Release 2.6 (2022-01-24)](release-notes/rl-2.6.md)
   - [Release 2.5 (2021-12-13)](release-notes/rl-2.5.md)

doc/manual/src/advanced-topics/diff-hook.md

@@ -101,7 +101,7 @@ In particular, notice the
 `/nix/store/krpqk0l9ib0ibi1d2w52z293zw455cap-unstable.check` output. Nix
 has copied the build results to that directory where you can examine it.
 
-> []{#check-dirs-are-unregistered} **Note**
+> **Note**
 > 
 > Check paths are not protected against garbage collection, and this
 > path will be deleted on the next garbage collection.

doc/manual/src/advanced-topics/distributed-builds.md

@@ -12,14 +12,14 @@ machine is accessible via SSH and that it has Nix installed. You can
 test whether connecting to the remote Nix instance works, e.g.
 
 ```console
-$ nix store ping --store ssh://mac
+$ nix ping-store --store ssh://mac
 ```
 
 will try to connect to the machine named `mac`. It is possible to
 specify an SSH identity file as part of the remote store URI, e.g.
 
 ```console
-$ nix store ping --store ssh://mac?ssh-key=/home/alice/my-key
+$ nix ping-store --store ssh://mac?ssh-key=/home/alice/my-key
 ```
 
 Since builds should be non-interactive, the key should not have a
@@ -110,7 +110,7 @@ default, set it to `-`.
 7.  A comma-separated list of *mandatory features*. A machine will only
     be used to build a derivation if all of the machine’s mandatory
     features appear in the derivation’s `requiredSystemFeatures`
-    attribute.
+    attribute..
 
 8.  The (base64-encoded) public host key of the remote machine. If omitted, SSH
     will use its regular known-hosts file. Specifically, the field is calculated

doc/manual/src/command-ref/env-common.md

@@ -2,11 +2,11 @@
 
 Most Nix commands interpret the following environment variables:
 
-  - [`IN_NIX_SHELL`]{#env-IN_NIX_SHELL}\
+  - `IN_NIX_SHELL`\
     Indicator that tells if the current environment was set up by
-    `nix-shell`. It can have the values `pure` or `impure`.
+    `nix-shell`. Since Nix 2.0 the values are `"pure"` and `"impure"`
 
-  - [`NIX_PATH`]{#env-NIX_PATH}\
+  - `NIX_PATH`\
     A colon-separated list of directories used to look up Nix
     expressions enclosed in angle brackets (i.e., `<path>`). For
     instance, the value
@@ -44,7 +44,7 @@ Most Nix commands interpret the following environment variables:
     The Nix search path can also be extended using the `-I` option to
     many Nix commands, which takes precedence over `NIX_PATH`.
 
-  - [`NIX_IGNORE_SYMLINK_STORE`]{#env-NIX_IGNORE_SYMLINK_STORE}\
+  - `NIX_IGNORE_SYMLINK_STORE`\
     Normally, the Nix store directory (typically `/nix/store`) is not
     allowed to contain any symlink components. This is to prevent
     “impure” builds. Builders sometimes “canonicalise” paths by
@@ -66,41 +66,41 @@ Most Nix commands interpret the following environment variables:
 
     Consult the mount 8 manual page for details.
 
-  - [`NIX_STORE_DIR`]{#env-NIX_STORE_DIR}\
+  - `NIX_STORE_DIR`\
     Overrides the location of the Nix store (default `prefix/store`).
 
-  - [`NIX_DATA_DIR`]{#env-NIX_DATA_DIR}\
+  - `NIX_DATA_DIR`\
     Overrides the location of the Nix static data directory (default
     `prefix/share`).
 
-  - [`NIX_LOG_DIR`]{#env-NIX_LOG_DIR}\
+  - `NIX_LOG_DIR`\
     Overrides the location of the Nix log directory (default
     `prefix/var/log/nix`).
 
-  - [`NIX_STATE_DIR`]{#env-NIX_STATE_DIR}\
+  - `NIX_STATE_DIR`\
     Overrides the location of the Nix state directory (default
     `prefix/var/nix`).
 
-  - [`NIX_CONF_DIR`]{#env-NIX_CONF_DIR}\
+  - `NIX_CONF_DIR`\
     Overrides the location of the system Nix configuration directory
     (default `prefix/etc/nix`).
 
-  - [`NIX_CONFIG`]{#env-NIX_CONFIG}\
+  - `NIX_CONFIG`\
     Applies settings from Nix configuration from the environment.
     The content is treated as if it was read from a Nix configuration file.
     Settings are separated by the newline character.
 
-  - [`NIX_USER_CONF_FILES`]{#env-NIX_USER_CONF_FILES}\
+  - `NIX_USER_CONF_FILES`\
     Overrides the location of the user Nix configuration files to load
     from (defaults to the XDG spec locations). The variable is treated
     as a list separated by the `:` token.
 
-  - [`TMPDIR`]{#env-TMPDIR}\
+  - `TMPDIR`\
     Use the specified directory to store temporary files. In particular,
     this includes temporary build directories; these can take up
     substantial amounts of disk space. The default is `/tmp`.
 
-  - [`NIX_REMOTE`]{#env-NIX_REMOTE}\
+  - `NIX_REMOTE`\
     This variable should be set to `daemon` if you want to use the Nix
     daemon to execute Nix operations. This is necessary in [multi-user
     Nix installations](../installation/multi-user.md). If the Nix
@@ -108,16 +108,16 @@ Most Nix commands interpret the following environment variables:
     should be set to `unix://path/to/socket`. Otherwise, it should be
     left unset.
 
-  - [`NIX_SHOW_STATS`]{#env-NIX_SHOW_STATS}\
+  - `NIX_SHOW_STATS`\
     If set to `1`, Nix will print some evaluation statistics, such as
     the number of values allocated.
 
-  - [`NIX_COUNT_CALLS`]{#env-NIX_COUNT_CALLS}\
+  - `NIX_COUNT_CALLS`\
     If set to `1`, Nix will print how often functions were called during
     Nix expression evaluation. This is useful for profiling your Nix
     expressions.
 
-  - [`GC_INITIAL_HEAP_SIZE`]{#env-GC_INITIAL_HEAP_SIZE}\
+  - `GC_INITIAL_HEAP_SIZE`\
     If Nix has been configured to use the Boehm garbage collector, this
     variable sets the initial size of the heap in bytes. It defaults to
     384 MiB. Setting it to a low value reduces memory consumption, but

doc/manual/src/command-ref/nix-build.md

@@ -12,12 +12,6 @@
   [`--dry-run`]
   [{`--out-link` | `-o`} *outlink*]
 
-# Disambiguation
-
-This man page describes the command `nix-build`, which is distinct from `nix
-build`. For documentation on the latter, run `nix build --help` or see `man
-nix3-build`.
-
 # Description
 
 The `nix-build` command builds the derivations described by the Nix
@@ -53,16 +47,16 @@ All options not listed here are passed to `nix-store
 --realise`, except for `--arg` and `--attr` / `-A` which are passed to
 `nix-instantiate`.
 
-  - [`--no-out-link`]{#opt-no-out-link}\
+  - `--no-out-link`\
     Do not create a symlink to the output path. Note that as a result
     the output does not become a root of the garbage collector, and so
     might be deleted by `nix-store
                     --gc`.
 
-  - [`--dry-run`]{#opt-dry-run}\
+  - `--dry-run`\
     Show what store paths would be built or downloaded.
 
-  - [`--out-link`]{#opt-out-link} / `-o` *outlink*\
+  - `--out-link` / `-o` *outlink*\
     Change the name of the symlink to the output path created from
     `result` to *outlink*.
 

doc/manual/src/command-ref/nix-copy-closure.md

@@ -30,8 +30,8 @@ Since `nix-copy-closure` calls `ssh`, you may be asked to type in the
 appropriate password or passphrase.  In fact, you may be asked _twice_
 because `nix-copy-closure` currently connects twice to the remote
 machine, first to get the set of paths missing on the target machine,
-and second to send the dump of those paths.  When using public key
-authentication, you can avoid typing the passphrase with `ssh-agent`.
+and second to send the dump of those paths.  If this bothers you, use
+`ssh-agent`.
 
 # Options
 

doc/manual/src/command-ref/nix-env.md

@@ -31,7 +31,7 @@ subcommand to be performed. These are documented below.
 Several commands, such as `nix-env -q` and `nix-env -i`, take a list of
 arguments that specify the packages on which to operate. These are
 extended regular expressions that must match the entire name of the
-package. (For details on regular expressions, see **regex**(7).) The match is
+package. (For details on regular expressions, see regex7.) The match is
 case-sensitive. The regular expression can optionally be followed by a
 dash and a version number; if omitted, any version of the package will
 match. Here are some examples:
@@ -198,7 +198,7 @@ a number of possible ways:
     another.
 
   - If `--from-expression` is given, *args* are Nix
-    [functions](../language/constructs.md#functions)
+    [functions](../expressions/language-constructs.md#functions)
     that are called with the active Nix expression as their single
     argument. The derivations returned by those function calls are
     installed. This allows derivations to be specified in an
@@ -412,7 +412,7 @@ The upgrade operation determines whether a derivation `y` is an upgrade
 of a derivation `x` by looking at their respective `name` attributes.
 The names (e.g., `gcc-3.3.1` are split into two parts: the package name
 (`gcc`), and the version (`3.3.1`). The version part starts after the
-first dash not followed by a letter. `y` is considered an upgrade of `x`
+first dash not followed by a letter. `x` is considered an upgrade of `y`
 if their package names match, and the version of `y` is higher than that
 of `x`.
 

doc/manual/src/command-ref/nix-instantiate.md

@@ -51,7 +51,7 @@ standard input.
   - `--strict`\
     When used with `--eval`, recursively evaluate list elements and
     attributes. Normally, such sub-expressions are left unevaluated
-    (since the Nix language is lazy).
+    (since the Nix expression language is lazy).
 
     > **Warning**
     >
@@ -66,7 +66,7 @@ standard input.
     When used with `--eval`, print the resulting value as an XML
     representation of the abstract syntax tree rather than as an ATerm.
     The schema is the same as that used by the [`toXML`
-    built-in](../language/builtins.md).
+    built-in](../expressions/builtins.md).
 
   - `--read-write-mode`\
     When used with `--eval`, perform evaluation in read/write mode so

doc/manual/src/command-ref/nix-shell.md

@@ -15,12 +15,6 @@
   [`--keep` *name*]
   {{`--packages` | `-p`} {*packages* | *expressions*} … | [*path*]}
 
-# Disambiguation
-
-This man page describes the command `nix-shell`, which is distinct from `nix
-shell`. For documentation on the latter, run `nix shell --help` or see `man
-nix3-shell`.
-
 # Description
 
 The command `nix-shell` will build the dependencies of the specified

doc/manual/src/command-ref/nix-store.md

@@ -22,7 +22,7 @@ This section lists the options that are common to all operations. These
 options are allowed for every subcommand, though they may not always
 have an effect.
 
-  - [`--add-root`]{#opt-add-root} *path*\
+  - `--add-root` *path*\
     Causes the result of a realisation (`--realise` and
     `--force-realise`) to be registered as a root of the garbage
     collector. *path* will be created as a symlink to the resulting
@@ -121,7 +121,7 @@ Special exit codes:
   - `102`\
     Hash mismatch, the build output was rejected because it does not
     match the [`outputHash` attribute of the
-    derivation](../language/advanced-attributes.md).
+    derivation](../expressions/advanced-attributes.md).
 
   - `104`\
     Not deterministic, the build succeeded in check mode but the

doc/manual/src/command-ref/opt-common.md

@@ -2,13 +2,13 @@
 
 Most Nix commands accept the following command-line options:
 
-  - [`--help`]{#opt-help}\
+  - `--help`\
     Prints out a summary of the command syntax and exits.
 
-  - [`--version`]{#opt-version}\
+  - `--version`\
     Prints out the Nix version number on standard output and exits.
 
-  - [`--verbose`]{#opt-verbose} / `-v`\
+  - `--verbose` / `-v`\
     Increases the level of verbosity of diagnostic messages printed on
     standard error. For each Nix operation, the information printed on
     standard output is well-defined; any diagnostic information is
@@ -37,14 +37,14 @@ Most Nix commands accept the following command-line options:
       - 5\
         “Vomit”: print vast amounts of debug information.
 
-  - [`--quiet`]{#opt-quiet}\
+  - `--quiet`\
     Decreases the level of verbosity of diagnostic messages printed on
     standard error. This is the inverse option to `-v` / `--verbose`.
 
     This option may be specified repeatedly. See the previous verbosity
     levels list.
 
-  - [`--log-format`]{#opt-log-format} *format*\
+  - `--log-format` *format*\
     This option can be used to change the output of the log format, with
     *format* being one of:
 
@@ -66,14 +66,14 @@ Most Nix commands accept the following command-line options:
       - bar-with-logs\
         Display the raw logs, with the progress bar at the bottom.
 
-  - [`--no-build-output`]{#opt-no-build-output} / `-Q`\
+  - `--no-build-output` / `-Q`\
     By default, output written by builders to standard output and
     standard error is echoed to the Nix command's standard error. This
     option suppresses this behaviour. Note that the builder's standard
     output and error are always written to a log file in
     `prefix/nix/var/log/nix`.
 
-  - [`--max-jobs`]{#opt-max-jobs} / `-j` *number*\
+  - `--max-jobs` / `-j` *number*\
     Sets the maximum number of build jobs that Nix will perform in
     parallel to the specified number. Specify `auto` to use the number
     of CPUs in the system. The default is specified by the `max-jobs`
@@ -83,7 +83,7 @@ Most Nix commands accept the following command-line options:
     Setting it to `0` disallows building on the local machine, which is
     useful when you want builds to happen only on remote builders.
 
-  - [`--cores`]{#opt-cores}\
+  - `--cores`\
     Sets the value of the `NIX_BUILD_CORES` environment variable in
     the invocation of builders. Builders can use this variable at
     their discretion to control the maximum amount of parallelism. For
@@ -94,18 +94,18 @@ Most Nix commands accept the following command-line options:
     means that the builder should use all available CPU cores in the
     system.
 
-  - [`--max-silent-time`]{#opt-max-silent-time}\
+  - `--max-silent-time`\
     Sets the maximum number of seconds that a builder can go without
     producing any data on standard output or standard error. The
     default is specified by the `max-silent-time` configuration
     setting. `0` means no time-out.
 
-  - [`--timeout`]{#opt-timeout}\
+  - `--timeout`\
     Sets the maximum number of seconds that a builder can run. The
     default is specified by the `timeout` configuration setting. `0`
     means no timeout.
 
-  - [`--keep-going`]{#opt-keep-going} / `-k`\
+  - `--keep-going` / `-k`\
     Keep going in case of failed builds, to the greatest extent
     possible. That is, if building an input of some derivation fails,
     Nix will still build the other inputs, but not the derivation
@@ -113,13 +113,13 @@ Most Nix commands accept the following command-line options:
     for builds of substitutes), possibly killing builds in progress (in
     case of parallel or distributed builds).
 
-  - [`--keep-failed`]{#opt-keep-failed} / `-K`\
+  - `--keep-failed` / `-K`\
     Specifies that in case of a build failure, the temporary directory
     (usually in `/tmp`) in which the build takes place should not be
     deleted. The path of the build directory is printed as an
     informational message.
 
-  - [`--fallback`]{#opt-fallback}\
+  - `--fallback`\
     Whenever Nix attempts to build a derivation for which substitutes
     are known for each output path, but realising the output paths
     through the substitutes fails, fall back on building the derivation.
@@ -134,18 +134,18 @@ Most Nix commands accept the following command-line options:
     failure in obtaining the substitutes to lead to a full build from
     source (with the related consumption of resources).
 
-  - [`--readonly-mode`]{#opt-readonly-mode}\
+  - `--readonly-mode`\
     When this option is used, no attempt is made to open the Nix
     database. Most Nix operations do need database access, so those
     operations will fail.
 
-  - [`--arg`]{#opt-arg} *name* *value*\
+  - `--arg` *name* *value*\
     This option is accepted by `nix-env`, `nix-instantiate`,
     `nix-shell` and `nix-build`. When evaluating Nix expressions, the
     expression evaluator will automatically try to call functions that
     it encounters. It can automatically call functions for which every
     argument has a [default
-    value](../language/constructs.md#functions) (e.g.,
+    value](../expressions/language-constructs.md#functions) (e.g.,
     `{ argName ?  defaultValue }: ...`). With `--arg`, you can also
     call functions that have arguments without a default value (or
     override a default value). That is, if the evaluator encounters a
@@ -164,19 +164,19 @@ Most Nix commands accept the following command-line options:
 
     So if you call this Nix expression (e.g., when you do `nix-env -iA
     pkgname`), the function will be called automatically using the
-    value [`builtins.currentSystem`](../language/builtins.md) for
+    value [`builtins.currentSystem`](../expressions/builtins.md) for
     the `system` argument. You can override this using `--arg`, e.g.,
     `nix-env -iA pkgname --arg system \"i686-freebsd\"`. (Note that
     since the argument is a Nix string literal, you have to escape the
     quotes.)
 
-  - [`--argstr`]{#opt-argstr} *name* *value*\
+  - `--argstr` *name* *value*\
     This option is like `--arg`, only the value is not a Nix
     expression but a string. So instead of `--arg system
     \"i686-linux\"` (the outer quotes are to keep the shell happy) you
     can say `--argstr system i686-linux`.
 
-  - [`--attr`]{#opt-attr} / `-A` *attrPath*\
+  - `--attr` / `-A` *attrPath*\
     Select an attribute from the top-level Nix expression being
     evaluated. (`nix-env`, `nix-instantiate`, `nix-build` and
     `nix-shell` only.) The *attribute path* *attrPath* is a sequence
@@ -191,7 +191,7 @@ Most Nix commands accept the following command-line options:
     attribute of the fourth element of the array in the `foo` attribute
     of the top-level expression.
 
-  - [`--expr`]{#opt-expr} / `-E`\
+  - `--expr` / `-E`\
     Interpret the command line arguments as a list of Nix expressions to
     be parsed and evaluated, rather than as a list of file names of Nix
     expressions. (`nix-instantiate`, `nix-build` and `nix-shell` only.)
@@ -202,17 +202,17 @@ Most Nix commands accept the following command-line options:
     use, give your expression to the `nix-shell -p` convenience flag
     instead.
 
-  - [`-I`]{#opt-I} *path*\
+  - `-I` *path*\
     Add a path to the Nix expression search path. This option may be
     given multiple times. See the `NIX_PATH` environment variable for
     information on the semantics of the Nix search path. Paths added
     through `-I` take precedence over `NIX_PATH`.
 
-  - [`--option`]{#opt-option} *name* *value*\
+  - `--option` *name* *value*\
     Set the Nix configuration option *name* to *value*. This overrides
     settings in the Nix configuration file (see nix.conf5).
 
-  - [`--repair`]{#opt-repair}\
+  - `--repair`\
     Fix corrupted or missing store paths by redownloading or rebuilding
     them. Note that this is slow because it requires computing a
     cryptographic hash of the contents of every path in the closure of

doc/manual/src/contributing/hacking.md

@@ -42,7 +42,7 @@ $ nix develop
 ```
 
 To get a shell with a different compilation environment (e.g. stdenv,
-gccStdenv, clangStdenv, clang11Stdenv, ccacheStdenv):
+gccStdenv, clangStdenv, clang11Stdenv):
 
 ```console
 $ nix-shell -A devShells.x86_64-linux.clang11StdenvPackages
@@ -54,9 +54,6 @@ or if you have a flake-enabled nix:
 $ nix develop .#clang11StdenvPackages
 ```
 
-Note: you can use `ccacheStdenv` to drastically improve rebuild
-time. By default, ccache keeps artifacts in `~/.cache/ccache/`.
-
 To build Nix itself in this shell:
 
 ```console
@@ -74,6 +71,18 @@ To install it in `$(pwd)/outputs` and test it:
 nix (Nix) 3.0
 ```
 
+To run a functional test:
+
+```console
+make tests/test-name-should-auto-complete.sh.test
+```
+
+To run the unit-tests for C++ code:
+
+```
+make check
+```
+
 If you have a flakes-enabled Nix you can replace:
 
 ```console
@@ -85,96 +94,3 @@ by:
 ```console
 $ nix develop
 ```
-
-## Running tests
-
-### Unit-tests
-
-The unit-tests for each Nix library (`libexpr`, `libstore`, etc..) are defined
-under `src/{library_name}/tests` using the
-[googletest](https://google.github.io/googletest/) framework.
-
-You can run the whole testsuite with `make check`, or the tests for a specific component with `make libfoo-tests_RUN`. Finer-grained filtering is also possible using the [--gtest_filter](https://google.github.io/googletest/advanced.html#running-a-subset-of-the-tests) command-line option.
-
-### Functional tests
-
-The functional tests reside under the `tests` directory and are listed in `tests/local.mk`.
-The whole testsuite can be run with `make install && make installcheck`.
-Individual tests can be run with `make tests/{testName}.sh.test`.
-
-### Integration tests
-
-The integration tests are defined in the Nix flake under the `hydraJobs.tests` attribute.
-These tests include everything that needs to interact with external services or run Nix in a non-trivial distributed setup.
-Because these tests are expensive and require more than what the standard github-actions setup provides, they only run on the master branch (on <https://hydra.nixos.org/jobset/nix/master>).
-
-You can run them manually with `nix build .#hydraJobs.tests.{testName}` or `nix-build -A hydraJobs.tests.{testName}`
-
-### Installer tests
-
-After a one-time setup, the Nix repository's GitHub Actions continuous integration (CI) workflow can test the installer each time you push to a branch.
-
-Creating a Cachix cache for your installer tests and adding its authorization token to GitHub enables [two installer-specific jobs in the CI workflow](https://github.com/NixOS/nix/blob/88a45d6149c0e304f6eb2efcc2d7a4d0d569f8af/.github/workflows/ci.yml#L50-L91):
-
-- The `installer` job generates installers for the platforms below and uploads them to your Cachix cache:
-  - `x86_64-linux`
-  - `armv6l-linux`
-  - `armv7l-linux`
-  - `x86_64-darwin`
-
-- The `installer_test` job (which runs on `ubuntu-latest` and `macos-latest`) will try to install Nix with the cached installer and run a trivial Nix command.
-
-#### One-time setup
-
-1. Have a GitHub account with a fork of the [Nix repository](https://github.com/NixOS/nix).
-2. At cachix.org:
-    - Create or log in to an account.
-    - Create a Cachix cache using the format `<github-username>-nix-install-tests`.
-    - Navigate to the new cache > Settings > Auth Tokens.
-    - Generate a new Cachix auth token and copy the generated value.
-3. At github.com:
-    - Navigate to your Nix fork > Settings > Secrets > Actions > New repository secret.
-    - Name the secret `CACHIX_AUTH_TOKEN`.
-    - Paste the copied value of the Cachix cache auth token.
-
-#### Using the CI-generated installer for manual testing
-
-After the CI run completes, you can check the output to extract the installer URL:
-1. Click into the detailed view of the CI run.
-2. Click into any `installer_test` run (the URL you're here to extract will be the same in all of them).
-3. Click into the `Run cachix/install-nix-action@v...` step and click the detail triangle next to the first log line (it will also be `Run cachix/install-nix-action@v...`)
-4. Copy the value of `install_url`
-5. To generate an install command, plug this `install_url` and your GitHub username into this template:
-
-    ```console
-    sh <(curl -L <install_url>) --tarball-url-prefix https://<github-username>-nix-install-tests.cachix.org/serve
-    ```
-
-<!-- #### Manually generating test installers
-
-There's obviously a manual way to do this, and it's still the only way for
-platforms that lack GA runners.
-
-I did do this back in Fall 2020 (before the GA approach encouraged here). I'll
-sketch what I recall in case it encourages someone to fill in detail, but: I
-didn't know what I was doing at the time and had to fumble/ask around a lot--
-so I don't want to uphold any of it as "right". It may have been dumb or
-the _hard_ way from the getgo. Fundamentals may have changed since.
-
-Here's the build command I used to do this on and for x86_64-darwin:
-nix build --out-link /tmp/foo ".#checks.x86_64-darwin.binaryTarball"
-
-I used the stable out-link to make it easier to script the next steps:
-link=$(readlink /tmp/foo)
-cp $link/*-darwin.tar.xz ~/somewheres
-
-I've lost the last steps and am just going from memory:
-
-From here, I think I had to extract and modify the `install` script to point
-it at this tarball (which I scped to my own site, but it might make more sense
-to just share them locally). I extracted this script once and then just
-search/replaced in it for each new build.
-
-The installer now supports a `--tarball-url-prefix` flag which _may_ have
-solved this need?
--->

doc/manual/src/expressions/advanced-attributes.md

@@ -2,7 +2,7 @@
 
 Derivations can declare some infrequently used optional attributes.
 
-  - [`allowedReferences`]{#adv-attr-allowedReferences}\
+  - `allowedReferences`\
     The optional attribute `allowedReferences` specifies a list of legal
     references (dependencies) of the output of the builder. For example,
 
@@ -17,7 +17,7 @@ Derivations can declare some infrequently used optional attributes.
     booting Linux don’t have accidental dependencies on other paths in
     the Nix store.
 
-  - [`allowedRequisites`]{#adv-attr-allowedRequisites}\
+  - `allowedRequisites`\
     This attribute is similar to `allowedReferences`, but it specifies
     the legal requisites of the whole closure, so all the dependencies
     recursively. For example,
@@ -30,7 +30,7 @@ Derivations can declare some infrequently used optional attributes.
     runtime dependency than `foobar`, and in addition it enforces that
     `foobar` itself doesn't introduce any other dependency itself.
 
-  - [`disallowedReferences`]{#adv-attr-disallowedReferences}\
+  - `disallowedReferences`\
     The optional attribute `disallowedReferences` specifies a list of
     illegal references (dependencies) of the output of the builder. For
     example,
@@ -42,7 +42,7 @@ Derivations can declare some infrequently used optional attributes.
     enforces that the output of a derivation cannot have a direct
     runtime dependencies on the derivation `foo`.
 
-  - [`disallowedRequisites`]{#adv-attr-disallowedRequisites}\
+  - `disallowedRequisites`\
     This attribute is similar to `disallowedReferences`, but it
     specifies illegal requisites for the whole closure, so all the
     dependencies recursively. For example,
@@ -55,7 +55,7 @@ Derivations can declare some infrequently used optional attributes.
     dependency on `foobar` or any other derivation depending recursively
     on `foobar`.
 
-  - [`exportReferencesGraph`]{#adv-attr-exportReferencesGraph}\
+  - `exportReferencesGraph`\
     This attribute allows builders access to the references graph of
     their inputs. The attribute is a list of inputs in the Nix store
     whose references graph the builder needs to know. The value of
@@ -84,7 +84,7 @@ Derivations can declare some infrequently used optional attributes.
     with a Nix store containing the closure of a bootable NixOS
     configuration).
 
-  - [`impureEnvVars`]{#adv-attr-impureEnvVars}\
+  - `impureEnvVars`\
     This attribute allows you to specify a list of environment variables
     that should be passed from the environment of the calling user to
     the builder. Usually, the environment is cleared completely when the
@@ -112,7 +112,7 @@ Derivations can declare some infrequently used optional attributes.
     > environmental variables come from the environment of the
     > `nix-build`.
 
-  - [`outputHash`]{#adv-attr-outputHash}; [`outputHashAlgo`]{#adv-attr-outputHashAlgo}; [`outputHashMode`]{#adv-attr-outputHashMode}\
+  - `outputHash`; `outputHashAlgo`; `outputHashMode`\
     These attributes declare that the derivation is a so-called
     *fixed-output derivation*, which means that a cryptographic hash of
     the output is already known in advance. When the build of a
@@ -208,7 +208,7 @@ Derivations can declare some infrequently used optional attributes.
     [`nix-hash` command](../command-ref/nix-hash.md) for information
     about converting to and from base-32 notation.)
     
-  - [`__contentAddressed`]{#adv-attr-__contentAddressed}
+  - `__contentAddressed`
     If this **experimental** attribute is set to true, then the derivation
     outputs will be stored in a content-addressed location rather than the
     traditional input-addressed one.
@@ -216,7 +216,7 @@ Derivations can declare some infrequently used optional attributes.
     
     Setting this attribute also requires setting `outputHashMode` and `outputHashAlgo` like for *fixed-output derivations* (see above).
 
-  - [`passAsFile`]{#adv-attr-passAsFile}\
+  - `passAsFile`\
     A list of names of attributes that should be passed via files rather
     than environment variables. For example, if you have
 
@@ -234,7 +234,7 @@ Derivations can declare some infrequently used optional attributes.
     builder, since most operating systems impose a limit on the size
     of the environment (typically, a few hundred kilobyte).
 
-  - [`preferLocalBuild`]{#adv-attr-preferLocalBuild}\
+  - `preferLocalBuild`\
     If this attribute is set to `true` and [distributed building is
     enabled](../advanced-topics/distributed-builds.md), then, if
     possible, the derivation will be built locally instead of forwarded
@@ -242,7 +242,7 @@ Derivations can declare some infrequently used optional attributes.
     where the cost of doing a download or remote build would exceed
     the cost of building locally.
 
-  - [`allowSubstitutes`]{#adv-attr-allowSubstitutes}\
+  - `allowSubstitutes`\
     If this attribute is set to `false`, then Nix will always build this
     derivation; it will not try to substitute its outputs. This is
     useful for very trivial derivations (such as `writeText` in Nixpkgs)

doc/manual/src/expressions/arguments-variables.md

@@ -0,0 +1,80 @@
+# Arguments and Variables
+
+The [Nix expression for GNU Hello](expression-syntax.md) is a
+function; it is missing some arguments that have to be filled in
+somewhere. In the Nix Packages collection this is done in the file
+`pkgs/top-level/all-packages.nix`, where all Nix expressions for
+packages are imported and called with the appropriate arguments. Here
+are some fragments of `all-packages.nix`, with annotations of what
+they mean:
+
+```nix
+...
+
+rec { ①
+
+  hello = import ../applications/misc/hello/ex-1 ② { ③
+    inherit fetchurl stdenv perl;
+  };
+
+  perl = import ../development/interpreters/perl { ④
+    inherit fetchurl stdenv;
+  };
+
+  fetchurl = import ../build-support/fetchurl {
+    inherit stdenv; ...
+  };
+
+  stdenv = ...;
+
+}
+```
+
+1.  This file defines a set of attributes, all of which are concrete
+    derivations (i.e., not functions). In fact, we define a *mutually
+    recursive* set of attributes. That is, the attributes can refer to
+    each other. This is precisely what we want since we want to “plug”
+    the various packages into each other.
+
+2.  Here we *import* the Nix expression for GNU Hello. The import
+    operation just loads and returns the specified Nix expression. In
+    fact, we could just have put the contents of the Nix expression
+    for GNU Hello in `all-packages.nix` at this point. That would be
+    completely equivalent, but it would make `all-packages.nix` rather
+    bulky.
+    
+    Note that we refer to `../applications/misc/hello/ex-1`, not
+    `../applications/misc/hello/ex-1/default.nix`. When you try to
+    import a directory, Nix automatically appends `/default.nix` to the
+    file name.
+
+3.  This is where the actual composition takes place. Here we *call* the
+    function imported from `../applications/misc/hello/ex-1` with a set
+    containing the things that the function expects, namely `fetchurl`,
+    `stdenv`, and `perl`. We use inherit again to use the attributes
+    defined in the surrounding scope (we could also have written
+    `fetchurl = fetchurl;`, etc.).
+    
+    The result of this function call is an actual derivation that can be
+    built by Nix (since when we fill in the arguments of the function,
+    what we get is its body, which is the call to `stdenv.mkDerivation`
+    in the [Nix expression for GNU Hello](expression-syntax.md)).
+    
+    > **Note**
+    > 
+    > Nixpkgs has a convenience function `callPackage` that imports and
+    > calls a function, filling in any missing arguments by passing the
+    > corresponding attribute from the Nixpkgs set, like this:
+    > 
+    > ```nix
+    > hello = callPackage ../applications/misc/hello/ex-1 { };
+    > ```
+    > 
+    > If necessary, you can set or override arguments:
+    > 
+    > ```nix
+    > hello = callPackage ../applications/misc/hello/ex-1 { stdenv = myStdenv; };
+    > ```
+
+4.  Likewise, we have to instantiate Perl, `fetchurl`, and the standard
+    environment.

doc/manual/src/expressions/build-script.md

@@ -0,0 +1,70 @@
+# Build Script
+
+Here is the builder referenced from Hello's Nix expression (stored in
+`pkgs/applications/misc/hello/ex-1/builder.sh`):
+
+```bash
+source $stdenv/setup ①
+
+PATH=$perl/bin:$PATH ②
+
+tar xvfz $src ③
+cd hello-*
+./configure --prefix=$out ④
+make ⑤
+make install
+```
+
+The builder can actually be made a lot shorter by using the *generic
+builder* functions provided by `stdenv`, but here we write out the build
+steps to elucidate what a builder does. It performs the following steps:
+
+1.  When Nix runs a builder, it initially completely clears the
+    environment (except for the attributes declared in the derivation).
+    This is done to prevent undeclared inputs from being used in the
+    build process. If for example the `PATH` contained `/usr/bin`, then
+    you might accidentally use `/usr/bin/gcc`.
+    
+    So the first step is to set up the environment. This is done by
+    calling the `setup` script of the standard environment. The
+    environment variable `stdenv` points to the location of the
+    standard environment being used. (It wasn't specified explicitly
+    as an attribute in Hello's Nix expression, but `mkDerivation` adds
+    it automatically.)
+
+2.  Since Hello needs Perl, we have to make sure that Perl is in the
+    `PATH`. The `perl` environment variable points to the location of
+    the Perl package (since it was passed in as an attribute to the
+    derivation), so `$perl/bin` is the directory containing the Perl
+    interpreter.
+
+3.  Now we have to unpack the sources. The `src` attribute was bound to
+    the result of fetching the Hello source tarball from the network, so
+    the `src` environment variable points to the location in the Nix
+    store to which the tarball was downloaded. After unpacking, we `cd`
+    to the resulting source directory.
+    
+    The whole build is performed in a temporary directory created in
+    `/tmp`, by the way. This directory is removed after the builder
+    finishes, so there is no need to clean up the sources afterwards.
+    Also, the temporary directory is always newly created, so you don't
+    have to worry about files from previous builds interfering with the
+    current build.
+
+4.  GNU Hello is a typical Autoconf-based package, so we first have to
+    run its `configure` script. In Nix every package is stored in a
+    separate location in the Nix store, for instance
+    `/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1`. Nix
+    computes this path by cryptographically hashing all attributes of
+    the derivation. The path is passed to the builder through the `out`
+    environment variable. So here we give `configure` the parameter
+    `--prefix=$out` to cause Hello to be installed in the expected
+    location.
+
+5.  Finally we build Hello (`make`) and install it into the location
+    specified by `out` (`make install`).
+
+If you are wondering about the absence of error checking on the result
+of various commands called in the builder: this is because the shell
+script is evaluated with Bash's `-e` option, which causes the script to
+be aborted if any command fails without an error check.

doc/manual/src/expressions/builtin-constants.md

@@ -14,7 +14,7 @@ Here are the constants built into the Nix expression evaluator:
     This allows a Nix expression to fall back gracefully on older Nix
     installations that don’t have the desired built-in function.
 
-  - [`builtins.currentSystem`]{#builtins-currentSystem}\
+  - `builtins.currentSystem`\
     The built-in value `currentSystem` evaluates to the Nix platform
     identifier for the Nix installation on which the expression is being
     evaluated, such as `"i686-linux"` or `"x86_64-darwin"`.

doc/manual/src/expressions/derivations.md

@@ -4,7 +4,7 @@ The most important built-in function is `derivation`, which is used to
 describe a single derivation (a build action). It takes as input a set,
 the attributes of which specify the inputs of the build.
 
-  - There must be an attribute named [`system`]{#attr-system} whose value must be a
+  - There must be an attribute named `system` whose value must be a
     string specifying a Nix system type, such as `"i686-linux"` or
     `"x86_64-darwin"`. (To figure out your system type, run `nix -vv
     --version`.) The build can only be performed on a machine and

doc/manual/src/expressions/expression-language.md

@@ -0,0 +1,12 @@
+# Nix Expression Language
+
+The Nix expression language is a pure, lazy, functional language. Purity
+means that operations in the language don't have side-effects (for
+instance, there is no variable assignment). Laziness means that
+arguments to functions are evaluated only when they are needed.
+Functional means that functions are “normal” values that can be passed
+around and manipulated in interesting ways. The language is not a
+full-featured, general purpose language. Its main job is to describe
+packages, compositions of packages, and the variability within packages.
+
+This section presents the various features of the language.

doc/manual/src/expressions/expression-syntax.md

@@ -0,0 +1,93 @@
+# Expression Syntax
+
+Here is a Nix expression for GNU Hello:
+
+```nix
+{ stdenv, fetchurl, perl }: ①
+
+stdenv.mkDerivation { ②
+  name = "hello-2.1.1"; ③
+  builder = ./builder.sh; ④
+  src = fetchurl { ⑤
+    url = "ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz";
+    sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
+  };
+  inherit perl; ⑥
+}
+```
+
+This file is actually already in the Nix Packages collection in
+`pkgs/applications/misc/hello/ex-1/default.nix`. It is customary to
+place each package in a separate directory and call the single Nix
+expression in that directory `default.nix`. The file has the following
+elements (referenced from the figure by number):
+
+1.  This states that the expression is a *function* that expects to be
+    called with three arguments: `stdenv`, `fetchurl`, and `perl`. They
+    are needed to build Hello, but we don't know how to build them here;
+    that's why they are function arguments. `stdenv` is a package that
+    is used by almost all Nix Packages; it provides a
+    “standard” environment consisting of the things you would expect
+    in a basic Unix environment: a C/C++ compiler (GCC, to be precise),
+    the Bash shell, fundamental Unix tools such as `cp`, `grep`, `tar`,
+    etc. `fetchurl` is a function that downloads files. `perl` is the
+    Perl interpreter.
+    
+    Nix functions generally have the form `{ x, y, ..., z }: e` where
+    `x`, `y`, etc. are the names of the expected arguments, and where
+    *e* is the body of the function. So here, the entire remainder of
+    the file is the body of the function; when given the required
+    arguments, the body should describe how to build an instance of
+    the Hello package.
+
+2.  So we have to build a package. Building something from other stuff
+    is called a *derivation* in Nix (as opposed to sources, which are
+    built by humans instead of computers). We perform a derivation by
+    calling `stdenv.mkDerivation`. `mkDerivation` is a function
+    provided by `stdenv` that builds a package from a set of
+    *attributes*. A set is just a list of key/value pairs where each
+    key is a string and each value is an arbitrary Nix
+    expression. They take the general form `{ name1 = expr1; ...
+    nameN = exprN; }`.
+
+3.  The attribute `name` specifies the symbolic name and version of
+    the package. Nix doesn't really care about these things, but they
+    are used by for instance `nix-env -q` to show a “human-readable”
+    name for packages. This attribute is required by `mkDerivation`.
+
+4.  The attribute `builder` specifies the builder. This attribute can
+    sometimes be omitted, in which case `mkDerivation` will fill in a
+    default builder (which does a `configure; make; make install`, in
+    essence). Hello is sufficiently simple that the default builder
+    would suffice, but in this case, we will show an actual builder
+    for educational purposes. The value `./builder.sh` refers to the
+    shell script shown in the [next section](build-script.md),
+    discussed below.
+
+5.  The builder has to know what the sources of the package are. Here,
+    the attribute `src` is bound to the result of a call to the
+    `fetchurl` function. Given a URL and a SHA-256 hash of the expected
+    contents of the file at that URL, this function builds a derivation
+    that downloads the file and checks its hash. So the sources are a
+    dependency that like all other dependencies is built before Hello
+    itself is built.
+    
+    Instead of `src` any other name could have been used, and in fact
+    there can be any number of sources (bound to different attributes).
+    However, `src` is customary, and it's also expected by the default
+    builder (which we don't use in this example).
+
+6.  Since the derivation requires Perl, we have to pass the value of the
+    `perl` function argument to the builder. All attributes in the set
+    are actually passed as environment variables to the builder, so
+    declaring an attribute
+
+    ```nix
+    perl = perl;
+    ```
+    
+    will do the trick: it binds an attribute `perl` to the function
+    argument which also happens to be called `perl`. However, it looks a
+    bit silly, so there is a shorter syntax. The `inherit` keyword
+    causes the specified attributes to be bound to whatever variables
+    with the same name happen to be in scope.

doc/manual/src/expressions/generic-builder.md

@@ -0,0 +1,66 @@
+# Generic Builder Syntax
+
+Recall that the [build script for GNU Hello](build-script.md) looked
+something like this:
+
+```bash
+PATH=$perl/bin:$PATH
+tar xvfz $src
+cd hello-*
+./configure --prefix=$out
+make
+make install
+```
+
+The builders for almost all Unix packages look like this — set up some
+environment variables, unpack the sources, configure, build, and
+install. For this reason the standard environment provides some Bash
+functions that automate the build process. Here is what a builder using
+the generic build facilities looks like:
+
+```bash
+buildInputs="$perl" ①
+
+source $stdenv/setup ②
+
+genericBuild ③
+```
+
+Here is what each line means:
+
+1.  The `buildInputs` variable tells `setup` to use the indicated
+    packages as “inputs”. This means that if a package provides a `bin`
+    subdirectory, it's added to `PATH`; if it has a `include`
+    subdirectory, it's added to GCC's header search path; and so on.
+    (This is implemented in a modular way: `setup` tries to source the
+    file `pkg/nix-support/setup-hook` of all dependencies. These “setup
+    hooks” can then set up whatever environment variables they want; for
+    instance, the setup hook for Perl sets the `PERL5LIB` environment
+    variable to contain the `lib/site_perl` directories of all inputs.)
+
+2.  The function `genericBuild` is defined in the file `$stdenv/setup`.
+
+3.  The final step calls the shell function `genericBuild`, which
+    performs the steps that were done explicitly in the previous build
+    script. The generic builder is smart enough to figure out whether
+    to unpack the sources using `gzip`, `bzip2`, etc.  It can be
+    customised in many ways; see the Nixpkgs manual for details.
+
+Discerning readers will note that the `buildInputs` could just as well
+have been set in the Nix expression, like this:
+
+```nix
+  buildInputs = [ perl ];
+```
+
+The `perl` attribute can then be removed, and the builder becomes even
+shorter:
+
+```bash
+source $stdenv/setup
+genericBuild
+```
+
+In fact, `mkDerivation` provides a default builder that looks exactly
+like that, so it is actually possible to omit the builder for Hello
+entirely.

doc/manual/src/expressions/language-operators.md

@@ -1,6 +1,6 @@
 # Operators
 
-The table below lists the operators in the Nix language, in
+The table below lists the operators in the Nix expression language, in
 order of precedence (from strongest to weakest binding).
 
 | Name                     | Syntax                              | Associativity | Description                                                                                                                                                                                                                   | Precedence |

doc/manual/src/expressions/language-values.md

@@ -0,0 +1,251 @@
+# Values
+
+## Simple Values
+
+Nix has the following basic data types:
+
+  - *Strings* can be written in three ways.
+    
+    The most common way is to enclose the string between double quotes,
+    e.g., `"foo bar"`. Strings can span multiple lines. The special
+    characters `"` and `\` and the character sequence `${` must be
+    escaped by prefixing them with a backslash (`\`). Newlines, carriage
+    returns and tabs can be written as `\n`, `\r` and `\t`,
+    respectively.
+    
+    You can include the result of an expression into a string by
+    enclosing it in `${...}`, a feature known as *antiquotation*. The
+    enclosed expression must evaluate to something that can be coerced
+    into a string (meaning that it must be a string, a path, or a
+    derivation). For instance, rather than writing
+    
+    ```nix
+    "--with-freetype2-library=" + freetype + "/lib"
+    ```
+    
+    (where `freetype` is a derivation), you can instead write the more
+    natural
+    
+    ```nix
+    "--with-freetype2-library=${freetype}/lib"
+    ```
+    
+    The latter is automatically translated to the former. A more
+    complicated example (from the Nix expression for
+    [Qt](http://www.trolltech.com/products/qt)):
+    
+    ```nix
+    configureFlags = "
+      -system-zlib -system-libpng -system-libjpeg
+      ${if openglSupport then "-dlopen-opengl
+        -L${mesa}/lib -I${mesa}/include
+        -L${libXmu}/lib -I${libXmu}/include" else ""}
+      ${if threadSupport then "-thread" else "-no-thread"}
+    ";
+    ```
+    
+    Note that Nix expressions and strings can be arbitrarily nested; in
+    this case the outer string contains various antiquotations that
+    themselves contain strings (e.g., `"-thread"`), some of which in
+    turn contain expressions (e.g., `${mesa}`).
+    
+    The second way to write string literals is as an *indented string*,
+    which is enclosed between pairs of *double single-quotes*, like so:
+    
+    ```nix
+    ''
+      This is the first line.
+      This is the second line.
+        This is the third line.
+    ''
+    ```
+    
+    This kind of string literal intelligently strips indentation from
+    the start of each line. To be precise, it strips from each line a
+    number of spaces equal to the minimal indentation of the string as a
+    whole (disregarding the indentation of empty lines). For instance,
+    the first and second line are indented two spaces, while the third
+    line is indented four spaces. Thus, two spaces are stripped from
+    each line, so the resulting string is
+    
+    ```nix
+    "This is the first line.\nThis is the second line.\n  This is the third line.\n"
+    ```
+    
+    Note that the whitespace and newline following the opening `''` is
+    ignored if there is no non-whitespace text on the initial line.
+    
+    Antiquotation (`${expr}`) is supported in indented strings.
+    
+    Since `${` and `''` have special meaning in indented strings, you
+    need a way to quote them. `$` can be escaped by prefixing it with
+    `''` (that is, two single quotes), i.e., `''$`. `''` can be escaped
+    by prefixing it with `'`, i.e., `'''`. `$` removes any special
+    meaning from the following `$`. Linefeed, carriage-return and tab
+    characters can be written as `''\n`, `''\r`, `''\t`, and `''\`
+    escapes any other character.
+    
+    Indented strings are primarily useful in that they allow multi-line
+    string literals to follow the indentation of the enclosing Nix
+    expression, and that less escaping is typically necessary for
+    strings representing languages such as shell scripts and
+    configuration files because `''` is much less common than `"`.
+    Example:
+    
+    ```nix
+    stdenv.mkDerivation {
+      ...
+      postInstall =
+        ''
+          mkdir $out/bin $out/etc
+          cp foo $out/bin
+          echo "Hello World" > $out/etc/foo.conf
+          ${if enableBar then "cp bar $out/bin" else ""}
+        '';
+      ...
+    }
+    ```
+    
+    Finally, as a convenience, *URIs* as defined in appendix B of
+    [RFC 2396](http://www.ietf.org/rfc/rfc2396.txt) can be written *as
+    is*, without quotes. For instance, the string
+    `"http://example.org/foo.tar.bz2"` can also be written as
+    `http://example.org/foo.tar.bz2`.
+
+  - Numbers, which can be *integers* (like `123`) or *floating point*
+    (like `123.43` or `.27e13`).
+    
+    Numbers are type-compatible: pure integer operations will always
+    return integers, whereas any operation involving at least one
+    floating point number will have a floating point number as a result.
+
+  - *Paths*, e.g., `/bin/sh` or `./builder.sh`. A path must contain at
+    least one slash to be recognised as such. For instance, `builder.sh`
+    is not a path: it's parsed as an expression that selects the
+    attribute `sh` from the variable `builder`. If the file name is
+    relative, i.e., if it does not begin with a slash, it is made
+    absolute at parse time relative to the directory of the Nix
+    expression that contained it. For instance, if a Nix expression in
+    `/foo/bar/bla.nix` refers to `../xyzzy/fnord.nix`, the absolute path
+    is `/foo/xyzzy/fnord.nix`.
+    
+    If the first component of a path is a `~`, it is interpreted as if
+    the rest of the path were relative to the user's home directory.
+    e.g. `~/foo` would be equivalent to `/home/edolstra/foo` for a user
+    whose home directory is `/home/edolstra`.
+    
+    Paths can also be specified between angle brackets, e.g.
+    `<nixpkgs>`. This means that the directories listed in the
+    environment variable `NIX_PATH` will be searched for the given file
+    or directory name.
+
+    Antiquotation is supported in any paths except those in angle brackets.
+    `./${foo}-${bar}.nix` is a more convenient way of writing 
+    `./. + "/" + foo + "-" + bar + ".nix"` or `./. + "/${foo}-${bar}.nix"`. At
+    least one slash must appear *before* any antiquotations for this to be
+    recognized as a path. `a.${foo}/b.${bar}` is a syntactically valid division
+    operation. `./a.${foo}/b.${bar}` is a path.
+
+  - *Booleans* with values `true` and `false`.
+
+  - The null value, denoted as `null`.
+
+## Lists
+
+Lists are formed by enclosing a whitespace-separated list of values
+between square brackets. For example,
+
+```nix
+[ 123 ./foo.nix "abc" (f { x = y; }) ]
+```
+
+defines a list of four elements, the last being the result of a call to
+the function `f`. Note that function calls have to be enclosed in
+parentheses. If they had been omitted, e.g.,
+
+```nix
+[ 123 ./foo.nix "abc" f { x = y; } ]
+```
+
+the result would be a list of five elements, the fourth one being a
+function and the fifth being a set.
+
+Note that lists are only lazy in values, and they are strict in length.
+
+## Sets
+
+Sets are really the core of the language, since ultimately the Nix
+language is all about creating derivations, which are really just sets
+of attributes to be passed to build scripts.
+
+Sets are just a list of name/value pairs (called *attributes*) enclosed
+in curly brackets, where each value is an arbitrary expression
+terminated by a semicolon. For example:
+
+```nix
+{ x = 123;
+  text = "Hello";
+  y = f { bla = 456; };
+}
+```
+
+This defines a set with attributes named `x`, `text`, `y`. The order of
+the attributes is irrelevant. An attribute name may only occur once.
+
+Attributes can be selected from a set using the `.` operator. For
+instance,
+
+```nix
+{ a = "Foo"; b = "Bar"; }.a
+```
+
+evaluates to `"Foo"`. It is possible to provide a default value in an
+attribute selection using the `or` keyword. For example,
+
+```nix
+{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"
+```
+
+will evaluate to `"Xyzzy"` because there is no `c` attribute in the set.
+
+You can use arbitrary double-quoted strings as attribute names:
+
+```nix
+{ "foo ${bar}" = 123; "nix-1.0" = 456; }."foo ${bar}"
+```
+
+This will evaluate to `123` (Assuming `bar` is antiquotable). In the
+case where an attribute name is just a single antiquotation, the quotes
+can be dropped:
+
+```nix
+{ foo = 123; }.${bar} or 456
+```
+
+This will evaluate to `123` if `bar` evaluates to `"foo"` when coerced
+to a string and `456` otherwise (again assuming `bar` is antiquotable).
+
+In the special case where an attribute name inside of a set declaration
+evaluates to `null` (which is normally an error, as `null` is not
+antiquotable), that attribute is simply not added to the set:
+
+```nix
+{ ${if foo then "bar" else null} = true; }
+```
+
+This will evaluate to `{}` if `foo` evaluates to `false`.
+
+A set that has a `__functor` attribute whose value is callable (i.e. is
+itself a function or a set with a `__functor` attribute whose value is
+callable) can be applied as if it were a function, with the set itself
+passed in first , e.g.,
+
+```nix
+let add = { __functor = self: x: x + self.x; };
+    inc = add // { x = 1; };
+in inc 1
+```
+
+evaluates to `2`. This can be used to attach metadata to a function
+without the caller needing to treat it specially, or to implement a form
+of object-oriented programming, for example.

doc/manual/src/expressions/simple-building-testing.md

@@ -0,0 +1,61 @@
+# Building and Testing
+
+You can now try to build Hello. Of course, you could do `nix-env -f . -iA
+hello`, but you may not want to install a possibly broken package just
+yet. The best way to test the package is by using the command
+`nix-build`, which builds a Nix expression and creates a symlink named
+`result` in the current directory:
+
+```console
+$ nix-build -A hello
+building path `/nix/store/632d2b22514d...-hello-2.1.1'
+hello-2.1.1/
+hello-2.1.1/intl/
+hello-2.1.1/intl/ChangeLog
+...
+
+$ ls -l result
+lrwxrwxrwx ... 2006-09-29 10:43 result -> /nix/store/632d2b22514d...-hello-2.1.1
+
+$ ./result/bin/hello
+Hello, world!
+```
+
+The `-A` option selects the `hello` attribute. This is faster than
+using the symbolic package name specified by the `name` attribute
+(which also happens to be `hello`) and is unambiguous (there can be
+multiple packages with the symbolic name `hello`, but there can be
+only one attribute in a set named `hello`).
+
+`nix-build` registers the `./result` symlink as a garbage collection
+root, so unless and until you delete the `./result` symlink, the output
+of the build will be safely kept on your system. You can use
+`nix-build`’s `-o` switch to give the symlink another name.
+
+Nix has transactional semantics. Once a build finishes successfully, Nix
+makes a note of this in its database: it registers that the path denoted
+by `out` is now “valid”. If you try to build the derivation again, Nix
+will see that the path is already valid and finish immediately. If a
+build fails, either because it returns a non-zero exit code, because Nix
+or the builder are killed, or because the machine crashes, then the
+output paths will not be registered as valid. If you try to build the
+derivation again, Nix will remove the output paths if they exist (e.g.,
+because the builder died half-way through `make
+install`) and try again. Note that there is no “negative caching”: Nix
+doesn't remember that a build failed, and so a failed build can always
+be repeated. This is because Nix cannot distinguish between permanent
+failures (e.g., a compiler error due to a syntax error in the source)
+and transient failures (e.g., a disk full condition).
+
+Nix also performs locking. If you run multiple Nix builds
+simultaneously, and they try to build the same derivation, the first Nix
+instance that gets there will perform the build, while the others block
+(or perform other derivations if available) until the build finishes:
+
+```console
+$ nix-build -A hello
+waiting for lock on `/nix/store/0h5b7hp8d4hqfrw8igvx97x1xawrjnac-hello-2.1.1x'
+```
+
+So it is always safe to run multiple instances of Nix in parallel (which
+isn’t the case with, say, `make`).

doc/manual/src/expressions/simple-expression.md

@@ -0,0 +1,23 @@
+# A Simple Nix Expression
+
+This section shows how to add and test the [GNU Hello
+package](http://www.gnu.org/software/hello/hello.html) to the Nix
+Packages collection. Hello is a program that prints out the text “Hello,
+world\!”.
+
+To add a package to the Nix Packages collection, you generally need to
+do three things:
+
+1.  Write a Nix expression for the package. This is a file that
+    describes all the inputs involved in building the package, such as
+    dependencies, sources, and so on.
+
+2.  Write a *builder*. This is a shell script that builds the package
+    from the inputs. (In fact, it can be written in any language, but
+    typically it's a `bash` shell script.)
+
+3.  Add the package to the file `pkgs/top-level/all-packages.nix`. The
+    Nix expression written in the first step is a *function*; it
+    requires other packages in order to build it. In this step you put
+    it all together, i.e., you call the function with the right
+    arguments to build the actual package.

doc/manual/src/expressions/writing-nix-expressions.md

@@ -0,0 +1,12 @@
+This chapter shows you how to write Nix expressions, which instruct Nix
+how to build packages. It starts with a simple example (a Nix expression
+for GNU Hello), and then moves on to a more in-depth look at the Nix
+expression language.
+
+> **Note**
+> 
+> This chapter is mostly about the Nix expression language. For more
+> extensive information on adding packages to the Nix Packages
+> collection (such as functions in the standard environment and coding
+> conventions), please consult [its
+> manual](http://nixos.org/nixpkgs/manual/).

doc/manual/src/glossary.md

@@ -1,100 +1,48 @@
 # Glossary
 
-  - [derivation]{#gloss-derivation}\
+  - derivation\
     A description of a build action. The result of a derivation is a
     store object. Derivations are typically specified in Nix expressions
-    using the [`derivation` primitive](language/derivations.md). These are
+    using the [`derivation` primitive](expressions/derivations.md). These are
     translated into low-level *store derivations* (implicitly by
     `nix-env` and `nix-build`, or explicitly by `nix-instantiate`).
 
-  - [content-addressed derivation]{#gloss-content-addressed-derivation}\
-    A derivation which has the
-    [`__contentAddressed`](language/advanced-attributes.md#adv-attr-__contentAddressed)
-    attribute set to `true`.
-
-  - [fixed-output derivation]{#gloss-fixed-output-derivation}\
-    A derivation which includes the
-    [`outputHash`](language/advanced-attributes.md#adv-attr-outputHash) attribute.
-
-  - [store]{#gloss-store}\
+  - store\
     The location in the file system where store objects live. Typically
     `/nix/store`.
 
-    From   the  perspective   of   the  location   where  Nix   is
-    invoked, the  Nix store can be  referred to
-    as a "_local_" or a "_remote_" one:
-
-    + A *local  store* exists  on the filesystem of
-      the machine where Nix is  invoked. You can use other
-      local stores  by passing  the `--store` flag  to the
-      `nix` command.  Local stores can be used for building derivations.
-
-    + A  *remote store*  exists  anywhere  other than  the
-      local  filesystem. One  example is  the `/nix/store`
-      directory on another machine,  accessed via `ssh` or
-      served by the `nix-serve` Perl script.
-
-  - [chroot store]{#gloss-chroot-store}\
-    A local store whose canonical path is anything other than `/nix/store`.
-
-  - [binary cache]{#gloss-binary-cache}\
-    A *binary cache* is a Nix store which uses a different format: its
-    metadata and signatures are kept in `.narinfo` files rather than in a
-    Nix database.  This different format simplifies serving store objects
-    over the network, but cannot host builds.  Examples of binary caches
-    include S3 buckets and the [NixOS binary
-    cache](https://cache.nixos.org).
-
-  - [store path]{#gloss-store-path}\
+  - store path\
     The location in the file system of a store object, i.e., an
     immediate child of the Nix store directory.
 
-  - [store object]{#gloss-store-object}\
+  - store object\
     A file that is an immediate child of the Nix store directory. These
     can be regular files, but also entire directory trees. Store objects
     can be sources (objects copied from outside of the store),
     derivation outputs (objects produced by running a build action), or
     derivations (files describing a build action).
 
-  - [input-addressed store object]{#gloss-input-addressed-store-object}\
-    A store object produced by building a
-    non-[content-addressed](#gloss-content-addressed-derivation),
-    non-[fixed-output](#gloss-fixed-output-derivation)
-    derivation.
-
-  - [output-addressed store object]{#gloss-output-addressed-store-object}\
-    A store object whose store path hashes its content.  This
-    includes derivations, the outputs of
-    [content-addressed derivations](#gloss-content-addressed-derivation),
-    and the outputs of
-    [fixed-output derivations](#gloss-fixed-output-derivation).
-
-  - [substitute]{#gloss-substitute}\
+  - substitute\
     A substitute is a command invocation stored in the Nix database that
     describes how to build a store object, bypassing the normal build
     mechanism (i.e., derivations). Typically, the substitute builds the
     store object by downloading a pre-built version of the store object
     from some server.
 
-  - [substituter]{#gloss-substituter}\
-    A *substituter* is an additional store from which Nix will
-    copy store objects it doesn't have.  For details, see the
-    [`substituters` option](command-ref/conf-file.html#conf-substituters).
-
-  - [purity]{#gloss-purity}\
+  - purity\
     The assumption that equal Nix derivations when run always produce
     the same output. This cannot be guaranteed in general (e.g., a
     builder can rely on external inputs such as the network or the
     system time) but the Nix model assumes it.
 
-  - [Nix expression]{#gloss-nix-expression}\
+  - Nix expression\
     A high-level description of software packages and compositions
     thereof. Deploying software using Nix entails writing Nix
     expressions for your packages. Nix expressions are translated to
     derivations that are stored in the Nix store. These derivations can
     then be built.
 
-  - [reference]{#gloss-reference}\
+  - reference\
     A store path `P` is said to have a reference to a store path `Q` if
     the store object at `P` contains the path `Q` somewhere. The
     *references* of a store path are the set of store paths to which it
@@ -104,11 +52,11 @@
     output paths), whereas an output path only references other output
     paths.
 
-  - [reachable]{#gloss-reachable}\
+  - reachable\
     A store path `Q` is reachable from another store path `P` if `Q`
     is in the *closure* of the *references* relation.
 
-  - [closure]{#gloss-closure}\
+  - closure\
     The closure of a store path is the set of store paths that are
     directly or indirectly “reachable” from that store path; that is,
     it’s the closure of the path under the *references* relation. For
@@ -123,34 +71,34 @@
     to path `Q`, then `Q` is in the closure of `P`. Further, if `Q`
     references `R` then `R` is also in the closure of `P`.
 
-  - [output path]{#gloss-output-path}\
+  - output path\
     A store path produced by a derivation.
 
-  - [deriver]{#gloss-deriver}\
+  - deriver\
     The deriver of an *output path* is the store
     derivation that built it.
 
-  - [validity]{#gloss-validity}\
+  - validity\
     A store path is considered *valid* if it exists in the file system,
     is listed in the Nix database as being valid, and if all paths in
     its closure are also valid.
 
-  - [user environment]{#gloss-user-env}\
+  - user environment\
     An automatically generated store object that consists of a set of
     symlinks to “active” applications, i.e., other store paths. These
     are generated automatically by
     [`nix-env`](command-ref/nix-env.md). See *profiles*.
 
-  - [profile]{#gloss-profile}\
+  - profile\
     A symlink to the current *user environment* of a user, e.g.,
     `/nix/var/nix/profiles/default`.
 
-  - [NAR]{#gloss-nar}\
+  - NAR\
     A *N*ix *AR*chive. This is a serialisation of a path in the Nix
     store. It can contain regular files, directories and symbolic
     links.  NARs are generated and unpacked using `nix-store --dump`
     and `nix-store --restore`.
-  - [`∅`]{#gloss-emtpy-set}\
+  - `∅` \
     The empty set symbol. In the context of profile history, this denotes a package is not present in a particular version of the profile.
-  - [`ε`]{#gloss-epsilon}\
+  - `ε` \
     The epsilon symbol. In the context of a package, this means the version is empty. More precisely, the derivation does not have a version attribute.

doc/manual/src/installation/installing-binary.md

@@ -13,7 +13,7 @@ for your platform:
 - multi-user on macOS
 
   > **Notes on read-only filesystem root in macOS 10.15 Catalina +**
-  >
+  > 
   > - It took some time to support this cleanly. You may see posts,
   >   examples, and tutorials using obsolete workarounds.
   > - Supporting it cleanly made macOS installs too complex to qualify
@@ -31,8 +31,8 @@ $ sh <(curl -L https://nixos.org/nix/install) --no-daemon
 ```
 
 This will perform a single-user installation of Nix, meaning that `/nix`
-is owned by the invoking user. You can run this under your usual user
-account or root. The script will invoke `sudo` to create `/nix`
+is owned by the invoking user. You should run this under your usual user
+account, *not* as root. The script will invoke `sudo` to create `/nix`
 if it doesn’t already exist. If you don’t have `sudo`, you should
 manually create `/nix` first as root, e.g.:
 
@@ -71,11 +71,11 @@ $ sh <(curl -L https://nixos.org/nix/install) --daemon
 
 The multi-user installation of Nix will create build users between the
 user IDs 30001 and 30032, and a group with the group ID 30000. You
-can run this under your usual user account or root. The script
+should run this under your usual user account, *not* as root. The script
 will invoke `sudo` as needed.
 
 > **Note**
->
+> 
 > If you need Nix to use a different group ID or user ID set, you will
 > have to download the tarball manually and [edit the install
 > script](#installing-from-a-binary-tarball).
@@ -84,9 +84,7 @@ The installer will modify `/etc/bashrc`, and `/etc/zshrc` if they exist.
 The installer will first back up these files with a `.backup-before-nix`
 extension. The installer will also create `/etc/profile.d/nix.sh`.
 
-## Uninstalling
-
-### Linux
+You can uninstall Nix with the following commands:
 
 ```console
 sudo rm -rf /etc/profile/nix.sh /etc/nix /nix ~root/.nix-profile ~root/.nix-defexpr ~root/.nix-channels ~/.nix-profile ~/.nix-defexpr ~/.nix-channels
@@ -97,114 +95,21 @@ sudo systemctl stop nix-daemon.service
 sudo systemctl disable nix-daemon.socket
 sudo systemctl disable nix-daemon.service
 sudo systemctl daemon-reload
+
+# If you are on macOS, you will need to run:
+sudo launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
+sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist
 ```
 
 There may also be references to Nix in `/etc/profile`, `/etc/bashrc`,
 and `/etc/zshrc` which you may remove.
 
-### macOS
-
-1. Edit `/etc/zshrc` and `/etc/bashrc` to remove the lines sourcing
-   `nix-daemon.sh`, which should look like this:
-
-   ```bash
-   # Nix
-   if [ -e '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh' ]; then
-     . '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh'
-   fi
-   # End Nix
-   ```
-
-   If these files haven't been altered since installing Nix you can simply put
-   the backups back in place:
-
-   ```console
-   sudo mv /etc/zshrc.backup-before-nix /etc/zshrc
-   sudo mv /etc/bashrc.backup-before-nix /etc/bashrc
-   ```
-
-   This will stop shells from sourcing the file and bringing everything you
-   installed using Nix in scope.
-
-2. Stop and remove the Nix daemon services:
-
-   ```console
-   sudo launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
-   sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist
-   sudo launchctl unload /Library/LaunchDaemons/org.nixos.darwin-store.plist
-   sudo rm /Library/LaunchDaemons/org.nixos.darwin-store.plist
-   ```
-
-   This stops the Nix daemon and prevents it from being started next time you
-   boot the system.
-
-3. Remove the `nixbld` group and the `_nixbuildN` users:
-
-   ```console
-   sudo dscl . -delete /Groups/nixbld
-   for u in $(sudo dscl . -list /Users | grep _nixbld); do sudo dscl . -delete /Users/$u; done
-   ```
-
-   This will remove all the build users that no longer serve a purpose.
-
-4. Edit fstab using `sudo vifs` to remove the line mounting the Nix Store
-   volume on `/nix`, which looks like
-   `UUID=<uuid> /nix apfs rw,noauto,nobrowse,suid,owners` or
-   `LABEL=Nix\040Store /nix apfs rw,nobrowse`. This will prevent automatic
-   mounting of the Nix Store volume.
-
-5. Edit `/etc/synthetic.conf` to remove the `nix` line. If this is the only
-   line in the file you can remove it entirely, `sudo rm /etc/synthetic.conf`.
-   This will prevent the creation of the empty `/nix` directory to provide a
-   mountpoint for the Nix Store volume.
-
-6. Remove the files Nix added to your system:
-
-   ```console
-   sudo rm -rf /etc/nix /var/root/.nix-profile /var/root/.nix-defexpr /var/root/.nix-channels ~/.nix-profile ~/.nix-defexpr ~/.nix-channels
-   ```
-
-   This gets rid of any data Nix may have created except for the store which is
-   removed next.
-
-7. Remove the Nix Store volume:
-
-   ```console
-   sudo diskutil apfs deleteVolume /nix
-   ```
-
-   This will remove the Nix Store volume and everything that was added to the
-   store.
-
-   If the output indicates that the command couldn't remove the volume, you should
-   make sure you don't have an _unmounted_ Nix Store volume. Look for a
-   "Nix Store" volume in the output of the following command:
-
-   ```console
-   diskutil list
-   ```
-
-   If you _do_ see a "Nix Store" volume, delete it by re-running the diskutil
-   deleteVolume command, but replace `/nix` with the store volume's `diskXsY`
-   identifier.
-
-> **Note**
->
-> After you complete the steps here, you will still have an empty `/nix`
-> directory. This is an expected sign of a successful uninstall. The empty
-> `/nix` directory will disappear the next time you reboot.
->
-> You do not have to reboot to finish uninstalling Nix. The uninstall is
-> complete. macOS (Catalina+) directly controls root directories and its
-> read-only root will prevent you from manually deleting the empty `/nix`
-> mountpoint.
-
-# macOS Installation
-[]{#sect-macos-installation-change-store-prefix}[]{#sect-macos-installation-encrypted-volume}[]{#sect-macos-installation-symlink}[]{#sect-macos-installation-recommended-notes}
+# macOS Installation <a name="sect-macos-installation-change-store-prefix"></a><a name="sect-macos-installation-encrypted-volume"></a><a name="sect-macos-installation-symlink"></a><a name="sect-macos-installation-recommended-notes"></a>
 <!-- Note: anchors above to catch permalinks to old explanations -->
 
 We believe we have ironed out how to cleanly support the read-only root
-on modern macOS. New installs will do this automatically.
+on modern macOS. New installs will do this automatically, and you can
+also re-run a new installer to convert your existing setup.
 
 This section previously detailed the situation, options, and trade-offs,
 but it now only outlines what the installer does. You don't need to know

doc/manual/src/language/index.md

@@ -1,33 +0,0 @@
-# Nix Language
-
-The Nix language is
-
-- *domain-specific*
-
-  It only exists for the Nix package manager:
-  to describe packages and configurations as well as their variants and compositions.
-  It is not intended for general purpose use.
-
-- *declarative*
-
-  There is no notion of executing sequential steps.
-  Dependencies between operations are established only through data.
-
-- *pure*
-
-  Values cannot change during computation.
-  Functions always produce the same output if their input does not change.
-
-- *functional*
-
-  Functions are like any other value.
-  Functions can be assigned to names, taken as arguments, or returned by functions.
-
-- *lazy*
-
-  Expressions are only evaluated when their value is needed.
-
-- *dynamically typed*
-
-  Type errors are only detected when expressions are evaluated.
-

doc/manual/src/language/values.md

@@ -1,261 +0,0 @@
-# Data Types
-
-## Primitives
-
-- <a id="type-string" href="#type-string">String</a>
-
-  *Strings* can be written in three ways.
-
-  The most common way is to enclose the string between double quotes,
-  e.g., `"foo bar"`. Strings can span multiple lines. The special
-  characters `"` and `\` and the character sequence `${` must be
-  escaped by prefixing them with a backslash (`\`). Newlines, carriage
-  returns and tabs can be written as `\n`, `\r` and `\t`,
-  respectively.
-
-  You can include the result of an expression into a string by
-  enclosing it in `${...}`, a feature known as *antiquotation*. The
-  enclosed expression must evaluate to something that can be coerced
-  into a string (meaning that it must be a string, a path, or a
-  derivation). For instance, rather than writing
-
-  ```nix
-  "--with-freetype2-library=" + freetype + "/lib"
-  ```
-
-  (where `freetype` is a derivation), you can instead write the more
-  natural
-
-  ```nix
-  "--with-freetype2-library=${freetype}/lib"
-  ```
-
-  The latter is automatically translated to the former. A more
-  complicated example (from the Nix expression for
-  [Qt](http://www.trolltech.com/products/qt)):
-
-  ```nix
-  configureFlags = "
-    -system-zlib -system-libpng -system-libjpeg
-    ${if openglSupport then "-dlopen-opengl
-      -L${mesa}/lib -I${mesa}/include
-      -L${libXmu}/lib -I${libXmu}/include" else ""}
-    ${if threadSupport then "-thread" else "-no-thread"}
-  ";
-  ```
-
-  Note that Nix expressions and strings can be arbitrarily nested; in
-  this case the outer string contains various antiquotations that
-  themselves contain strings (e.g., `"-thread"`), some of which in
-  turn contain expressions (e.g., `${mesa}`).
-
-  The second way to write string literals is as an *indented string*,
-  which is enclosed between pairs of *double single-quotes*, like so:
-
-  ```nix
-  ''
-    This is the first line.
-    This is the second line.
-      This is the third line.
-  ''
-  ```
-
-  This kind of string literal intelligently strips indentation from
-  the start of each line. To be precise, it strips from each line a
-  number of spaces equal to the minimal indentation of the string as a
-  whole (disregarding the indentation of empty lines). For instance,
-  the first and second line are indented two spaces, while the third
-  line is indented four spaces. Thus, two spaces are stripped from
-  each line, so the resulting string is
-
-  ```nix
-  "This is the first line.\nThis is the second line.\n  This is the third line.\n"
-  ```
-
-  Note that the whitespace and newline following the opening `''` is
-  ignored if there is no non-whitespace text on the initial line.
-
-  Antiquotation (`${expr}`) is supported in indented strings.
-
-  Since `${` and `''` have special meaning in indented strings, you
-  need a way to quote them. `$` can be escaped by prefixing it with
-  `''` (that is, two single quotes), i.e., `''$`. `''` can be escaped
-  by prefixing it with `'`, i.e., `'''`. `$` removes any special
-  meaning from the following `$`. Linefeed, carriage-return and tab
-  characters can be written as `''\n`, `''\r`, `''\t`, and `''\`
-  escapes any other character.
-
-  Indented strings are primarily useful in that they allow multi-line
-  string literals to follow the indentation of the enclosing Nix
-  expression, and that less escaping is typically necessary for
-  strings representing languages such as shell scripts and
-  configuration files because `''` is much less common than `"`.
-  Example:
-
-  ```nix
-  stdenv.mkDerivation {
-    ...
-    postInstall =
-      ''
-        mkdir $out/bin $out/etc
-        cp foo $out/bin
-        echo "Hello World" > $out/etc/foo.conf
-        ${if enableBar then "cp bar $out/bin" else ""}
-      '';
-    ...
-  }
-  ```
-
-  Finally, as a convenience, *URIs* as defined in appendix B of
-  [RFC 2396](http://www.ietf.org/rfc/rfc2396.txt) can be written *as
-  is*, without quotes. For instance, the string
-  `"http://example.org/foo.tar.bz2"` can also be written as
-  `http://example.org/foo.tar.bz2`.
-
-- <a id="type-number" href="#type-number">Number</a>
-
-  Numbers, which can be *integers* (like `123`) or *floating point*
-  (like `123.43` or `.27e13`).
-
-  Numbers are type-compatible: pure integer operations will always
-  return integers, whereas any operation involving at least one
-  floating point number will have a floating point number as a result.
-
-- <a id="type-path" href="#type-path">Path</a>
-
-  *Paths*, e.g., `/bin/sh` or `./builder.sh`. A path must contain at
-  least one slash to be recognised as such. For instance, `builder.sh`
-  is not a path: it's parsed as an expression that selects the
-  attribute `sh` from the variable `builder`. If the file name is
-  relative, i.e., if it does not begin with a slash, it is made
-  absolute at parse time relative to the directory of the Nix
-  expression that contained it. For instance, if a Nix expression in
-  `/foo/bar/bla.nix` refers to `../xyzzy/fnord.nix`, the absolute path
-  is `/foo/xyzzy/fnord.nix`.
-
-  If the first component of a path is a `~`, it is interpreted as if
-  the rest of the path were relative to the user's home directory.
-  e.g. `~/foo` would be equivalent to `/home/edolstra/foo` for a user
-  whose home directory is `/home/edolstra`.
-
-  Paths can also be specified between angle brackets, e.g.
-  `<nixpkgs>`. This means that the directories listed in the
-  environment variable `NIX_PATH` will be searched for the given file
-  or directory name.
-
-  Antiquotation is supported in any paths except those in angle brackets.
-  `./${foo}-${bar}.nix` is a more convenient way of writing
-  `./. + "/" + foo + "-" + bar + ".nix"` or `./. + "/${foo}-${bar}.nix"`. At
-  least one slash must appear *before* any antiquotations for this to be
-  recognized as a path. `a.${foo}/b.${bar}` is a syntactically valid division
-  operation. `./a.${foo}/b.${bar}` is a path.
-
-- <a id="type-boolean" href="#type-boolean">Boolean</a>
-
-  *Booleans* with values `true` and `false`.
-
-- <a id="type-null" href="#type-null">Null</a>
-
-  The null value, denoted as `null`.
-
-## List
-
-Lists are formed by enclosing a whitespace-separated list of values
-between square brackets. For example,
-
-```nix
-[ 123 ./foo.nix "abc" (f { x = y; }) ]
-```
-
-defines a list of four elements, the last being the result of a call to
-the function `f`. Note that function calls have to be enclosed in
-parentheses. If they had been omitted, e.g.,
-
-```nix
-[ 123 ./foo.nix "abc" f { x = y; } ]
-```
-
-the result would be a list of five elements, the fourth one being a
-function and the fifth being a set.
-
-Note that lists are only lazy in values, and they are strict in length.
-
-## Attribute Set
-
-An attribute set is a collection of name-value-pairs (called *attributes*) enclosed in curly brackets (`{ }`).
-
-Names and values are separated by an equal sign (`=`).
-Each value is an arbitrary expression terminated by a semicolon (`;`).
-
-Attributes can appear in any order.
-An attribute name may only occur once.
-
-Example:
-
-```nix
-{
-  x = 123;
-  text = "Hello";
-  y = f { bla = 456; };
-}
-```
-
-This defines a set with attributes named `x`, `text`, `y`.
-
-Attributes can be selected from a set using the `.` operator. For
-instance,
-
-```nix
-{ a = "Foo"; b = "Bar"; }.a
-```
-
-evaluates to `"Foo"`. It is possible to provide a default value in an
-attribute selection using the `or` keyword. For example,
-
-```nix
-{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"
-```
-
-will evaluate to `"Xyzzy"` because there is no `c` attribute in the set.
-
-You can use arbitrary double-quoted strings as attribute names:
-
-```nix
-{ "foo ${bar}" = 123; "nix-1.0" = 456; }."foo ${bar}"
-```
-
-This will evaluate to `123` (Assuming `bar` is antiquotable). In the
-case where an attribute name is just a single antiquotation, the quotes
-can be dropped:
-
-```nix
-{ foo = 123; }.${bar} or 456
-```
-
-This will evaluate to `123` if `bar` evaluates to `"foo"` when coerced
-to a string and `456` otherwise (again assuming `bar` is antiquotable).
-
-In the special case where an attribute name inside of a set declaration
-evaluates to `null` (which is normally an error, as `null` is not
-antiquotable), that attribute is simply not added to the set:
-
-```nix
-{ ${if foo then "bar" else null} = true; }
-```
-
-This will evaluate to `{}` if `foo` evaluates to `false`.
-
-A set that has a `__functor` attribute whose value is callable (i.e. is
-itself a function or a set with a `__functor` attribute whose value is
-callable) can be applied as if it were a function, with the set itself
-passed in first , e.g.,
-
-```nix
-let add = { __functor = self: x: x + self.x; };
-    inc = add // { x = 1; };
-in inc 1
-```
-
-evaluates to `2`. This can be used to attach metadata to a function
-without the caller needing to treat it specially, or to implement a form
-of object-oriented programming, for example.

doc/manual/src/package-management/package-management.md

@@ -1,4 +1,5 @@
 This chapter discusses how to do package management with Nix, i.e.,
 how to obtain, install, upgrade, and erase packages. This is the
 “user’s” perspective of the Nix system — people who want to *create*
-packages should consult the chapter on the [Nix language](../language/index.md).
+packages should consult the [chapter on writing Nix
+expressions](../expressions/writing-nix-expressions.md).

doc/manual/src/release-notes/rl-2.10.md

@@ -1,31 +0,0 @@
-# Release 2.10 (2022-07-11)
-
-* `nix repl` now takes installables on the command line, unifying the usage
-  with other commands that use `--file` and `--expr`. Primary breaking change
-  is for the common usage of `nix repl '<nixpkgs>'` which can be recovered with
-  `nix repl --file '<nixpkgs>'` or `nix repl --expr 'import <nixpkgs>{}'`.
-
-  This is currently guarded by the `repl-flake` experimental feature.
-
-* A new function `builtins.traceVerbose` is available. It is similar
-  to `builtins.trace` if the `trace-verbose` setting is set to true,
-  and it is a no-op otherwise.
-
-* `nix search` has a new flag `--exclude` to filter out packages.
-
-* On Linux, if `/nix` doesn't exist and cannot be created and you're
-  not running as root, Nix will automatically use
-  `~/.local/share/nix/root` as a chroot store. This enables non-root
-  users to download the statically linked Nix binary and have it work
-  out of the box, e.g.
-
-  ```
-  # ~/nix run nixpkgs#hello
-  warning: '/nix' does not exists, so Nix will use '/home/ubuntu/.local/share/nix/root' as a chroot store
-  Hello, world!
-  ```
-
-* `flake-registry.json` is now fetched from `channels.nixos.org`.
-
-* Nix can now be built with LTO by passing `--enable-lto` to `configure`.
-  LTO is currently only supported when building with GCC.

doc/manual/src/release-notes/rl-2.11.md

@@ -1,5 +0,0 @@
-# Release 2.11 (2022-08-24)
-
-* `nix copy` now copies the store paths in parallel as much as possible (again).
-  This doesn't apply for the `daemon` and `ssh-ng` stores which copy everything
-  in one batch to avoid latencies issues.

doc/manual/src/release-notes/rl-2.8.md

@@ -1,53 +0,0 @@
-# Release 2.8 (2022-04-19)
-
-* New experimental command: `nix fmt`, which applies a formatter
-  defined by the `formatter.<system>` flake output to the Nix
-  expressions in a flake.
-
-* Various Nix commands can now read expressions from standard input
-  using `--file -`.
-
-* New experimental builtin function `builtins.fetchClosure` that
-  copies a closure from a binary cache at evaluation time and rewrites
-  it to content-addressed form (if it isn't already). Like
-  `builtins.storePath`, this allows importing pre-built store paths;
-  the difference is that it doesn't require the user to configure
-  binary caches and trusted public keys.
-
-  This function is only available if you enable the experimental
-  feature `fetch-closure`.
-
-* New experimental feature: *impure derivations*. These are
-  derivations that can produce a different result every time they're
-  built. Here is an example:
-
-  ```nix
-  stdenv.mkDerivation {
-    name = "impure";
-    __impure = true; # marks this derivation as impure
-    buildCommand = "date > $out";
-  }
-  ```
-
-  Running `nix build` twice on this expression will build the
-  derivation twice, producing two different content-addressed store
-  paths. Like fixed-output derivations, impure derivations have access
-  to the network. Only fixed-output derivations and impure derivations
-  can depend on an impure derivation.
-
-* `nix store make-content-addressable` has been renamed to `nix store
-  make-content-addressed`.
-
-* The `nixosModule` flake output attribute has been renamed consistent
-  with the `.default` renames in Nix 2.7.
-
-  * `nixosModule` → `nixosModules.default`
-
-  As before, the old output will continue to work, but `nix flake check` will
-  issue a warning about it.
-
-* `nix run` is now stricter in what it accepts: members of the `apps`
-  flake output are now required to be apps (as defined in [the
-  manual](https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-run.html#apps)),
-  and members of `packages` or `legacyPackages` must be derivations
-  (not apps).

doc/manual/src/release-notes/rl-2.9.md

@@ -1,47 +0,0 @@
-# Release 2.9 (2022-05-30)
-
-* Running Nix with the new `--debugger` flag will cause it to start a
-  repl session if an exception is thrown during evaluation, or if
-  `builtins.break` is called.  From there you can inspect the values
-  of variables and evaluate Nix expressions.  In debug mode, the
-  following new repl commands are available:
-
-  ```
-  :env          Show env stack
-  :bt           Show trace stack
-  :st           Show current trace
-  :st <idx>     Change to another trace in the stack
-  :c            Go until end of program, exception, or builtins.break().
-  :s            Go one step
-  ```
-
-  Read more about the debugger
-  [here](https://www.zknotes.com/note/5970).
-
-* Nix now provides better integration with zsh's `run-help`
-  feature. It is now included in the Nix installation in the form of
-  an autoloadable shell function, `run-help-nix`. It picks up Nix
-  subcommands from the currently typed in command and directs the user
-  to the associated man pages.
-
-* `nix repl` has a new build-and-link (`:bl`) command that builds a
-  derivation while creating GC root symlinks.
-
-* The path produced by `builtins.toFile` is now allowed to be imported
-  or read even with restricted evaluation. Note that this will not
-  work with a read-only store.
-
-* `nix build` has a new `--print-out-paths` flag to print the
-  resulting output paths.  This matches the default behaviour of
-  `nix-build`.
-
-* You can now specify which outputs of a derivation `nix` should
-  operate on using the syntax `installable^outputs`,
-  e.g. `nixpkgs#glibc^dev,static` or `nixpkgs#glibc^*`. By default,
-  `nix` will use the outputs specified by the derivation's
-  `meta.outputsToInstall` attribute if it exists, or all outputs
-  otherwise.
-
-* `builtins.fetchTree` (and flake inputs) can now be used to fetch
-  plain files over the `http(s)` and `file` protocols in addition to
-  directory tarballs.

doc/manual/src/release-notes/rl-next.md

@@ -1,7 +1 @@
 # Release X.Y (202?-??-??)
-
-* `<nix/fetchurl.nix>` now accepts an additional argument `impure` which
-  defaults to `false`.  If it is set to `true`, the `hash` and `sha256`
-  arguments will be ignored and the resulting derivation will have
-  `__impure` set to `true`, making it an impure derivation.
-

doc/manual/utils.nix

@@ -5,32 +5,6 @@ rec {
 
   concatStrings = concatStringsSep "";
 
-  replaceStringsRec = from: to: string:
-    # recursively replace occurrences of `from` with `to` within `string`
-    # example:
-    #     replaceStringRec "--" "-" "hello-----world"
-    #     => "hello-world"
-    let
-      replaced = replaceStrings [ from ] [ to ] string;
-    in
-      if replaced == string then string else replaceStringsRec from to replaced;
-
-  squash = replaceStringsRec "\n\n\n" "\n\n";
-
-  trim = string:
-    # trim trailing spaces and squash non-leading spaces
-    let
-      trimLine = line:
-        let
-          # separate leading spaces from the rest
-          parts = split "(^ *)" line;
-          spaces = head (elemAt parts 1);
-          rest = elemAt parts 2;
-          # drop trailing spaces
-          body = head (split " *$" rest);
-        in spaces + replaceStringsRec "  " " " body;
-    in concatStringsSep "\n" (map trimLine (splitLines string));
-
   # FIXME: O(n^2)
   unique = foldl' (acc: e: if elem e acc then acc else acc ++ [ e ]) [];
 

docker.nix

@@ -2,12 +2,8 @@
 , lib ? pkgs.lib
 , name ? "nix"
 , tag ? "latest"
-, bundleNixpkgs ? true
 , channelName ? "nixpkgs"
 , channelURL ? "https://nixos.org/channels/nixpkgs-unstable"
-, extraPkgs ? []
-, maxLayers ? 100
-, nixConf ? {}
 }:
 let
   defaultPkgs = with pkgs; [
@@ -26,14 +22,13 @@ let
     findutils
     iana-etc
     git
-    openssh
-  ] ++ extraPkgs;
+  ];
 
   users = {
 
     root = {
       uid = 0;
-      shell = "${pkgs.bashInteractive}/bin/bash";
+      shell = "/bin/bash";
       home = "/root";
       gid = 0;
     };
@@ -125,27 +120,20 @@ let
       (lib.attrValues (lib.mapAttrs groupToGroup groups))
   );
 
-  defaultNixConf = {
+  nixConf = {
     sandbox = "false";
     build-users-group = "nixbld";
-    trusted-public-keys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ];
+    trusted-public-keys = "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=";
   };
-
-  nixConfContents = (lib.concatStringsSep "\n" (lib.mapAttrsFlatten (n: v:
-    let
-      vStr = if builtins.isList v then lib.concatStringsSep " " v else v;
-    in
-      "${n} = ${vStr}") (defaultNixConf // nixConf))) + "\n";
+  nixConfContents = (lib.concatStringsSep "\n" (lib.mapAttrsFlatten (n: v: "${n} = ${v}") nixConf)) + "\n";
 
   baseSystem =
     let
       nixpkgs = pkgs.path;
-      channel = pkgs.runCommand "channel-nixos" { inherit bundleNixpkgs; } ''
+      channel = pkgs.runCommand "channel-nixos" { } ''
         mkdir $out
-        if [ "$bundleNixpkgs" ]; then
-          ln -s ${nixpkgs} $out/nixpkgs
-          echo "[]" > $out/manifest.nix
-        fi
+        ln -s ${nixpkgs} $out/nixpkgs
+        echo "[]" > $out/manifest.nix
       '';
       rootEnv = pkgs.buildPackages.buildEnv {
         name = "root-profile-env";
@@ -240,7 +228,7 @@ let
 in
 pkgs.dockerTools.buildLayeredImageWithNixDb {
 
-  inherit name tag maxLayers;
+  inherit name tag;
 
   contents = [ baseSystem ];
 

flake.lock

@@ -18,18 +18,17 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1657693803,
-        "narHash": "sha256-G++2CJ9u0E7NNTAi9n5G8TdDmGJXcIjkJ3NF8cetQB8=",
+        "lastModified": 1656604668,
+        "narHash": "sha256-5g8ll8kgstMtdAhKdAfkv5YuhmxVE+77IuFBubK3i3k=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "365e1b3a859281cf11b94f87231adeabbdd878a2",
+        "rev": "e1029c6170ccec08a5fc0123a4cca1779a0cd43d",
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
+        "id": "nixpkgs",
         "ref": "nixos-22.05-small",
-        "repo": "nixpkgs",
-        "type": "github"
+        "type": "indirect"
       }
     },
     "nixpkgs-regression": {
@@ -42,10 +41,9 @@
         "type": "github"
       },
       "original": {
-        "owner": "NixOS",
-        "repo": "nixpkgs",
+        "id": "nixpkgs",
         "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
-        "type": "github"
+        "type": "indirect"
       }
     },
     "root": {

flake.nix

@@ -1,8 +1,8 @@
 {
   description = "The purely functional package manager";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.05-small";
-  inputs.nixpkgs-regression.url = "github:NixOS/nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2";
+  inputs.nixpkgs.url = "nixpkgs/nixos-22.05-small";
+  inputs.nixpkgs-regression.url = "nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2";
   inputs.lowdown-src = { url = "github:kristapsdz/lowdown"; flake = false; };
 
   outputs = { self, nixpkgs, nixpkgs-regression, lowdown-src }:
@@ -15,7 +15,7 @@
         then ""
         else "pre${builtins.substring 0 8 (self.lastModifiedDate or self.lastModified or "19700101")}_${self.shortRev or "dirty"}";
 
-      officialRelease = false;
+      officialRelease = true;
 
       linux64BitSystems = [ "x86_64-linux" "aarch64-linux" ];
       linuxSystems = linux64BitSystems ++ [ "i686-linux" ];
@@ -23,7 +23,7 @@
 
       crossSystems = [ "armv6l-linux" "armv7l-linux" ];
 
-      stdenvs = [ "gccStdenv" "clangStdenv" "clang11Stdenv" "stdenv" "libcxxStdenv" "ccacheStdenv" ];
+      stdenvs = [ "gccStdenv" "clangStdenv" "clang11Stdenv" "stdenv" ];
 
       forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
       forAllSystemsAndStdenvs = f: forAllSystems (system:
@@ -36,7 +36,7 @@
           )
       );
 
-      forAllStdenvs = f: nixpkgs.lib.genAttrs stdenvs (stdenv: f stdenv);
+      forAllStdenvs = stdenvs: f: nixpkgs.lib.genAttrs stdenvs (stdenv: f stdenv);
 
       # Memoize nixpkgs for different platforms for efficiency.
       nixpkgsFor =
@@ -54,7 +54,7 @@
         # we want most of the time and for backwards compatibility
         forAllSystems (system: stdenvsPackages.${system} // stdenvsPackages.${system}.stdenvPackages);
 
-      commonDeps = { pkgs, isStatic ? false }: with pkgs; rec {
+      commonDeps = pkgs: with pkgs; rec {
         # Use "busybox-sandbox-shell" if present,
         # if not (legacy) fallback and hope it's sufficient.
         sh = pkgs.busybox-sandbox-shell or (busybox.override {
@@ -85,11 +85,10 @@
           lib.optionals stdenv.isLinux [
             "--with-boost=${boost}/lib"
             "--with-sandbox-shell=${sh}/bin/busybox"
-          ]
-          ++ lib.optionals (stdenv.isLinux && !(isStatic && stdenv.system == "aarch64-linux")) [
             "LDFLAGS=-fuse-ld=gold"
           ];
 
+
         nativeBuildDeps =
           [
             buildPackages.bison
@@ -103,12 +102,12 @@
             # Tests
             buildPackages.git
             buildPackages.mercurial # FIXME: remove? only needed for tests
-            buildPackages.jq # Also for custom mdBook preprocessor.
+            buildPackages.jq
           ]
           ++ lib.optionals stdenv.hostPlatform.isLinux [(buildPackages.util-linuxMinimal or buildPackages.utillinuxMinimal)];
 
         buildDeps =
-          [ (curl.override { patchNetrcRegression = true; })
+          [ curl
             bzip2 xz brotli editline
             openssl sqlite
             libarchive
@@ -136,6 +135,11 @@
             }))
             nlohmann_json
           ];
+
+        perlDeps =
+          [ perl
+            perlPackages.DBDSQLite
+          ];
       };
 
       installScriptFor = systems:
@@ -172,7 +176,7 @@
             echo "file installer $out/install" >> $out/nix-support/hydra-build-products
           '';
 
-      testNixVersions = pkgs: client: daemon: with commonDeps { inherit pkgs; }; with pkgs.lib; pkgs.stdenv.mkDerivation {
+      testNixVersions = pkgs: client: daemon: with commonDeps pkgs; with pkgs.lib; pkgs.stdenv.mkDerivation {
         NIX_DAEMON_PACKAGE = daemon;
         NIX_CLIENT_PACKAGE = client;
         name =
@@ -260,7 +264,6 @@
             echo "file binary-dist $fn" >> $out/nix-support/hydra-build-products
             tar cvfJ $fn \
               --owner=0 --group=0 --mode=u+rw,uga+r \
-              --mtime='1970-01-01' \
               --absolute-names \
               --hard-dereference \
               --transform "s,$TMPDIR/install,$dir/install," \
@@ -284,7 +287,7 @@
           # Forward from the previous stage as we don’t want it to pick the lowdown override
           nixUnstable = prev.nixUnstable;
 
-          nix = with final; with commonDeps { inherit pkgs; }; currentStdenv.mkDerivation {
+          nix = with final; with commonDeps pkgs; currentStdenv.mkDerivation {
             name = "nix-${version}";
             inherit version;
 
@@ -316,7 +319,6 @@
                   for LIB in $out/lib/*.dylib; do
                     chmod u+w $LIB
                     install_name_tool -id $LIB $LIB
-                    install_name_tool -delete_rpath ${boost}/lib/ $LIB || true
                   done
                   install_name_tool -change ${boost}/lib/libboost_system.dylib $out/lib/libboost_system.dylib $out/lib/libboost_thread.dylib
                 ''}
@@ -351,7 +353,7 @@
 
             strictDeps = true;
 
-            passthru.perl-bindings = with final; perl.pkgs.toPerlModule (currentStdenv.mkDerivation {
+            passthru.perl-bindings = with final; currentStdenv.mkDerivation {
               name = "nix-perl-${version}";
 
               src = self;
@@ -364,7 +366,7 @@
 
               buildInputs =
                 [ nix
-                  (curl.override { patchNetrcRegression = true; })
+                  curl
                   bzip2
                   xz
                   pkgs.perl
@@ -373,17 +375,16 @@
                 ++ lib.optional (currentStdenv.isLinux || currentStdenv.isDarwin) libsodium
                 ++ lib.optional currentStdenv.isDarwin darwin.apple_sdk.frameworks.Security;
 
-              configureFlags = [
-                "--with-dbi=${perlPackages.DBI}/${pkgs.perl.libPrefix}"
-                "--with-dbd-sqlite=${perlPackages.DBDSQLite}/${pkgs.perl.libPrefix}"
-              ];
+              configureFlags = ''
+                --with-dbi=${perlPackages.DBI}/${pkgs.perl.libPrefix}
+                --with-dbd-sqlite=${perlPackages.DBDSQLite}/${pkgs.perl.libPrefix}
+              '';
 
               enableParallelBuilding = true;
 
               postUnpack = "sourceRoot=$sourceRoot/perl";
-            });
+            };
 
-            meta.platforms = systems;
           };
 
           lowdown-nix = with final; currentStdenv.mkDerivation rec {
@@ -402,13 +403,30 @@
                   BINDIR=${placeholder "bin"}/bin
             '';
           };
+          nix-find-roots = prev.stdenv.mkDerivation {
+            name = "nix-find-roots-${version}";
+            inherit version;
+
+            src = "${self}/src/nix-find-roots";
+
+            CXXFLAGS = prev.lib.optionalString prev.stdenv.hostPlatform.isStatic "-static";
+
+            buildPhase = ''
+              $CXX $CXXFLAGS -std=c++17 *.cc **/*.cc -I lib -o nix-find-roots
+            '';
+
+            installPhase = ''
+              mkdir -p $out/bin
+              cp nix-find-roots $out/bin/
+            '';
+          };
         };
 
     in {
 
       # A Nixpkgs overlay that overrides the 'nix' and
       # 'nix.perl-bindings' packages.
-      overlays.default = overlayFor (p: p.stdenv);
+      overlay = overlayFor (p: p.stdenv);
 
       hydraJobs = {
 
@@ -433,7 +451,7 @@
           value = let
             nixpkgsCross = import nixpkgs {
               inherit system crossSystem;
-              overlays = [ self.overlays.default ];
+              overlays = [ self.overlay ];
             };
           in binaryTarball nixpkgsFor.${system} self.packages.${system}."nix-${crossSystem}" nixpkgsCross;
         }) crossSystems));
@@ -451,7 +469,7 @@
         # Line coverage analysis.
         coverage =
           with nixpkgsFor.x86_64-linux;
-          with commonDeps { inherit pkgs; };
+          with commonDeps pkgs;
 
           releaseTools.coverageAnalysis {
             name = "nix-coverage-${version}";
@@ -479,31 +497,31 @@
         tests.remoteBuilds = import ./tests/remote-builds.nix {
           system = "x86_64-linux";
           inherit nixpkgs;
-          overlay = self.overlays.default;
+          inherit (self) overlay;
         };
 
         tests.nix-copy-closure = import ./tests/nix-copy-closure.nix {
           system = "x86_64-linux";
           inherit nixpkgs;
-          overlay = self.overlays.default;
+          inherit (self) overlay;
         };
 
         tests.nssPreload = (import ./tests/nss-preload.nix rec {
           system = "x86_64-linux";
           inherit nixpkgs;
-          overlay = self.overlays.default;
+          inherit (self) overlay;
         });
 
         tests.githubFlakes = (import ./tests/github-flakes.nix rec {
           system = "x86_64-linux";
           inherit nixpkgs;
-          overlay = self.overlays.default;
+          inherit (self) overlay;
         });
 
         tests.sourcehutFlakes = (import ./tests/sourcehut-flakes.nix rec {
           system = "x86_64-linux";
           inherit nixpkgs;
-          overlay = self.overlays.default;
+          inherit (self) overlay;
         });
 
         tests.setuid = nixpkgs.lib.genAttrs
@@ -511,7 +529,7 @@
           (system:
             import ./tests/setuid.nix rec {
               inherit nixpkgs system;
-              overlay = self.overlays.default;
+              inherit (self) overlay;
             });
 
         # Make sure that nix-env still produces the exact same result
@@ -546,11 +564,6 @@
             # againstLatestStable = testNixVersions pkgs pkgs.nix pkgs.nixStable;
           } "touch $out");
 
-        installerTests = import ./tests/installer {
-          binaryTarballs = self.hydraJobs.binaryTarball;
-          inherit nixpkgsFor;
-        };
-
       };
 
       checks = forAllSystems (system: {
@@ -561,13 +574,13 @@
         dockerImage = self.hydraJobs.dockerImage.${system};
       });
 
-      packages = forAllSystems (system: rec {
+      packages = forAllSystems (system: {
         inherit (nixpkgsFor.${system}) nix;
-        default = nix;
       } // (nixpkgs.lib.optionalAttrs (builtins.elem system linux64BitSystems) {
+        inherit (nixpkgsFor.${system}.pkgsStatic) nix-find-roots;
         nix-static = let
           nixpkgs = nixpkgsFor.${system}.pkgsStatic;
-        in with commonDeps { pkgs = nixpkgs; isStatic = true; }; nixpkgs.stdenv.mkDerivation {
+        in with commonDeps nixpkgs; nixpkgs.stdenv.mkDerivation {
           name = "nix-${version}";
 
           src = self;
@@ -579,24 +592,14 @@
           nativeBuildInputs = nativeBuildDeps;
           buildInputs = buildDeps ++ propagatedDeps;
 
-          # Work around pkgsStatic disabling all tests.
-          # Remove in NixOS 22.11, see https://github.com/NixOS/nixpkgs/pull/140271.
-          preHook =
-            ''
-              doCheck=1
-              doInstallCheck=1
-            '';
-
-          configureFlags =
-            configureFlags ++
-            [ "--sysconfdir=/etc"
-              "--enable-embedded-sandbox-shell"
-            ];
+          configureFlags = [ "--sysconfdir=/etc" ];
 
           enableParallelBuilding = true;
 
           makeFlags = "profiledir=$(out)/etc/profile.d";
 
+          doCheck = true;
+
           installFlags = "sysconfdir=$(out)/etc";
 
           postInstall = ''
@@ -606,6 +609,7 @@
             echo "file binary-dist $out/bin/nix" >> $out/nix-support/hydra-build-products
           '';
 
+          doInstallCheck = true;
           installCheckFlags = "sysconfdir=$(out)/etc";
 
           stripAllList = ["bin"];
@@ -614,7 +618,6 @@
 
           hardeningDisable = [ "pie" ];
         };
-
         dockerImage =
           let
             pkgs = nixpkgsFor.${system};
@@ -629,16 +632,14 @@
               ln -s ${image} $image
               echo "file binary-dist $image" >> $out/nix-support/hydra-build-products
             '';
-      }
-
-      // builtins.listToAttrs (map (crossSystem: {
+      } // builtins.listToAttrs (map (crossSystem: {
         name = "nix-${crossSystem}";
         value = let
           nixpkgsCross = import nixpkgs {
             inherit system crossSystem;
-            overlays = [ self.overlays.default ];
+            overlays = [ self.overlay ];
           };
-        in with commonDeps { pkgs = nixpkgsCross; }; nixpkgsCross.stdenv.mkDerivation {
+        in with commonDeps nixpkgsCross; nixpkgsCross.stdenv.mkDerivation {
           name = "nix-${version}";
 
           src = self;
@@ -670,45 +671,44 @@
           doInstallCheck = true;
           installCheckFlags = "sysconfdir=$(out)/etc";
         };
-      }) (if system == "x86_64-linux" then crossSystems else [])))
-
-      // (builtins.listToAttrs (map (stdenvName:
+      }) crossSystems)) // (builtins.listToAttrs (map (stdenvName:
         nixpkgsFor.${system}.lib.nameValuePair
           "nix-${stdenvName}"
           nixpkgsFor.${system}."${stdenvName}Packages".nix
       ) stdenvs)));
 
-      devShells = forAllSystems (system:
-        forAllStdenvs (stdenv:
-          with nixpkgsFor.${system};
-          with commonDeps { inherit pkgs; };
-          nixpkgsFor.${system}.${stdenv}.mkDerivation {
-            name = "nix";
+      defaultPackage = forAllSystems (system: self.packages.${system}.nix);
 
-            outputs = [ "out" "dev" "doc" ];
+      devShell = forAllSystems (system: self.devShells.${system}.stdenvPackages);
 
-            nativeBuildInputs = nativeBuildDeps;
-            buildInputs = buildDeps ++ propagatedDeps ++ awsDeps;
+      devShells = forAllSystemsAndStdenvs (system: stdenv:
+        with nixpkgsFor.${system};
+        with commonDeps pkgs;
 
-            inherit configureFlags;
+        nixpkgsFor.${system}.${stdenv}.mkDerivation {
+          name = "nix";
 
-            enableParallelBuilding = true;
+          outputs = [ "out" "dev" "doc" ];
 
-            installFlags = "sysconfdir=$(out)/etc";
+          nativeBuildInputs = nativeBuildDeps;
+          buildInputs = buildDeps ++ propagatedDeps ++ awsDeps ++ perlDeps;
 
-            shellHook =
-              ''
-                PATH=$prefix/bin:$PATH
-                unset PYTHONPATH
-                export MANPATH=$out/share/man:$MANPATH
+          inherit configureFlags;
 
-                # Make bash completion work.
-                XDG_DATA_DIRS+=:$out/share
-              '';
-          }
-        )
-        // { default = self.devShells.${system}.stdenv; }
-      );
+          enableParallelBuilding = true;
+
+          installFlags = "sysconfdir=$(out)/etc";
+
+          shellHook =
+            ''
+              PATH=$prefix/bin:$PATH
+              unset PYTHONPATH
+              export MANPATH=$out/share/man:$MANPATH
+
+              # Make bash completion work.
+              XDG_DATA_DIRS+=:$out/share
+            '';
+        });
 
   };
 }

misc/bash/completion.sh

@@ -15,7 +15,7 @@ function _complete_nix {
         else
             COMPREPLY+=("$completion")
         fi
-    done < <(NIX_GET_COMPLETIONS=$cword "${words[@]}" 2>/dev/null)
+    done < <(NIX_GET_COMPLETIONS=$cword "${words[@]/#\~/$HOME}" 2>/dev/null)
     __ltrim_colon_completions "$cur"
 }
 

misc/systemd/local.mk

@@ -1,8 +1,7 @@
 ifdef HOST_LINUX
 
   $(foreach n, nix-daemon.socket nix-daemon.service, $(eval $(call install-file-in, $(d)/$(n), $(prefix)/lib/systemd/system, 0644)))
-  $(foreach n, nix-daemon.conf, $(eval $(call install-file-in, $(d)/$(n), $(prefix)/lib/tmpfiles.d, 0644)))
 
-  clean-files += $(d)/nix-daemon.socket $(d)/nix-daemon.service $(d)/nix-daemon.conf
+  clean-files += $(d)/nix-daemon.socket $(d)/nix-daemon.service
 
 endif

misc/systemd/nix-daemon.conf.in

@@ -1 +0,0 @@
-d @localstatedir@/nix/daemon-socket 0755 root root - -

misc/systemd/nix-daemon.service.in

@@ -1,15 +1,12 @@
 [Unit]
 Description=Nix Daemon
-Documentation=man:nix-daemon https://nixos.org/manual
 RequiresMountsFor=@storedir@
 RequiresMountsFor=@localstatedir@
-RequiresMountsFor=@localstatedir@/nix/db
 ConditionPathIsReadWrite=@localstatedir@/nix/daemon-socket
 
 [Service]
 ExecStart=@@bindir@/nix-daemon nix-daemon --daemon
 KillMode=process
-LimitNOFILE=4096
 
 [Install]
 WantedBy=multi-user.target

misc/zsh/completion.zsh

@@ -10,15 +10,14 @@ function _nix() {
   local -a suggestions
   declare -a suggestions
   for suggestion in ${res:1}; do
-    suggestions+=("${suggestion%%	*}")
+    # FIXME: This doesn't work properly if the suggestion word contains a `:`
+    # itself
+    suggestions+="${suggestion/	/:}"
   done
-  local -a args
   if [[ "$tpe" == filenames ]]; then
-    args+=('-f')
-  elif [[ "$tpe" == attrs ]]; then
-    args+=('-S' '')
+    compadd -f
   fi
-  compadd -J nix "${args[@]}" -a suggestions
+  _describe 'nix' suggestions
 }
 
 _nix "$@"

misc/zsh/local.mk

@@ -1,2 +1 @@
 $(eval $(call install-file-as, $(d)/completion.zsh, $(datarootdir)/zsh/site-functions/_nix, 0644))
-$(eval $(call install-file-as, $(d)/run-help-nix, $(datarootdir)/zsh/site-functions/run-help-nix, 0644))

misc/zsh/run-help-nix

@@ -1,42 +0,0 @@
-emulate -L zsh
-
-# run-help is a zsh widget that can be bound to a key. It mainly looks up the
-# man page for the currently typed in command.
-#
-# Although run-help works for any command without requiring special support,
-# it can only deduce the right man page based solely on the name of the
-# command. Programs like Nix provide better integration with run-help by
-# helping zsh identify Nix subcommands and their corresponding man pages. This
-# is what this function does.
-#
-# To actually use run-help on zsh, place the following lines in your .zshrc:
-#
-#     (( $+aliases[run-help] )) && unalias run-help
-#     autoload -Uz run-help run-help-nix
-#
-# Then also assign run-help to any key of choice:
-#
-#     bindkey '^[h' run-help
-
-while [[ "$#" != 0 && "$1" == -* ]]; do
-  shift
-done
-
-local -a subcommands; subcommands=( nix3 )
-
-local arg
-for arg in "$@"; do
-  if man -w "${(j:-:)subcommands}-$arg" >/dev/null 2>&1; then
-    subcommands+="$arg"
-  else
-    break
-  fi
-done
-
-if (( $#subcommands > 1 )); then
-  man "${(j:-:)subcommands}"
-else
-  man nix
-fi
-
-return $?

mk/libraries.mk

@@ -91,7 +91,7 @@ define build-library
     $(1)_PATH := $$(_d)/$$($(1)_NAME).$(SO_EXT)
 
     $$($(1)_PATH): $$($(1)_OBJS) $$(_libs) | $$(_d)/
-	+$$(trace-ld) $(CXX) -o $$(abspath $$@) -shared $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$($(1)_LDFLAGS_PROPAGATED) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE)) $$($(1)_LDFLAGS_UNINSTALLED)
+	$$(trace-ld) $(CXX) -o $$(abspath $$@) -shared $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$($(1)_LDFLAGS_PROPAGATED) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE)) $$($(1)_LDFLAGS_UNINSTALLED)
 
     ifndef HOST_DARWIN
       $(1)_LDFLAGS_USE += -Wl,-rpath,$$(abspath $$(_d))
@@ -105,7 +105,7 @@ define build-library
     $$(eval $$(call create-dir, $$($(1)_INSTALL_DIR)))
 
     $$($(1)_INSTALL_PATH): $$($(1)_OBJS) $$(_libs_final) | $(DESTDIR)$$($(1)_INSTALL_DIR)/
-	+$$(trace-ld) $(CXX) -o $$@ -shared $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$($(1)_LDFLAGS_PROPAGATED) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE_INSTALLED))
+	$$(trace-ld) $(CXX) -o $$@ -shared $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$($(1)_LDFLAGS_PROPAGATED) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE_INSTALLED))
 
     $(1)_LDFLAGS_USE_INSTALLED += -L$$(DESTDIR)$$($(1)_INSTALL_DIR) -l$$(patsubst lib%,%,$$(strip $$($(1)_NAME)))
     ifndef HOST_DARWIN
@@ -125,7 +125,7 @@ define build-library
     $(1)_PATH := $$(_d)/$$($(1)_NAME).a
 
     $$($(1)_PATH): $$($(1)_OBJS) | $$(_d)/
-	+$$(trace-ld) $(LD) -Ur -o $$(_d)/$$($(1)_NAME).o $$^
+	$$(trace-ld) $(LD) -Ur -o $$(_d)/$$($(1)_NAME).o $$?
 	$$(trace-ar) $(AR) crs $$@ $$(_d)/$$($(1)_NAME).o
 
     $(1)_LDFLAGS_USE += $$($(1)_PATH) $$($(1)_LDFLAGS)

mk/programs.mk

@@ -32,7 +32,7 @@ define build-program
   $$(eval $$(call create-dir, $$(_d)))
 
   $$($(1)_PATH): $$($(1)_OBJS) $$(_libs) | $$(_d)/
-	+$$(trace-ld) $(CXX) -o $$@ $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE))
+	$$(trace-ld) $(CXX) -o $$@ $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE))
 
   $(1)_INSTALL_DIR ?= $$(bindir)
 
@@ -49,7 +49,7 @@ define build-program
       _libs_final := $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_INSTALL_PATH))
 
       $(DESTDIR)$$($(1)_INSTALL_PATH): $$($(1)_OBJS) $$(_libs_final) | $(DESTDIR)$$($(1)_INSTALL_DIR)/
-	+$$(trace-ld) $(CXX) -o $$@ $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE_INSTALLED))
+	$$(trace-ld) $(CXX) -o $$@ $$(LDFLAGS) $$(GLOBAL_LDFLAGS) $$($(1)_OBJS) $$($(1)_LDFLAGS) $$(foreach lib, $$($(1)_LIBS), $$($$(lib)_LDFLAGS_USE_INSTALLED))
 
     else
 

roadmap.md

@@ -1,85 +0,0 @@
-# Nix is everywhere
-
-Nix is the universal build and [configuration management] tool.
-
-[configuration management]: https://www.sebokwiki.org/wiki/Configuration_Management
-
-Software developers use Nix as a matter of course every day, mostly without even noticing.
-Nix runs trivially, anywhere.
-
-For individuals to large organizations, Nix underpins the entire software supply chain:
-- Developer tooling
-- Build automation
-- Binary distribution
-
-To this end, the Nix team will work towards the following goals.
-
-## Make Nix easy to adopt
-
-  - Well-defined target user base
-      - anyone who wants to manage the complexity of - and build - software
-      - transform bits in a declarative and reproducible way
-  - Well-defined core user stories
-    - Ad hoc environments
-        - One-liner setup (nix-shell)
-    - Declarative environments
-        - One-liner setup ("templates")
-        - Easy modification/extension
-        - Easy and transparent usage ("direnv"/"lorri")
-    - Secret management as first-class citizen
-    - Configurations as first-class citizens
-        - Configuration/Modules/Nickel/etc.
-    - Language bindings
-    - Supply chain trust solution
-        - Content-addressed derivation
-        - Build result signing, key distribution
-        - SBOM/SLSA
-    - Unprivileged installation and use
-        <!-- valentin: this needs clarification, I still don't know what rewriting is -->
-        - Portable store?
-        - restricted-root
-        - ACLs
-        - rewriting
-    - ...
-  - Linux, MacOS and Windows support at feature parity
-
-## Make Nix a tool that users can rely on
-
-  - Reliable installer
-  - Effective testing
-    - Test coverage for all major use cases
-    - Memory safety validation (sanitizers, ...)
-    - Benchmarking infrastructure
-    - Test reports published and accessible
-  - Executable language specification
- 
-## Make Nix a good investment for users
-
-  - Explicit compatibility guarantees (and non-guarantees)
-    - Commitment to uncompromising reproducibility
-    - Well-defined release process
-    - Feature support status
-    - Deprecation strategy
-    - LTS commitments
-    - Close Flakes schism, remove uncertanity/ambiguity/confusion
-
-  - Exemplary contributor and maintainer experience
-    - Recommended development setup
-    - Testing guidance
-    - Formalize review criteria
-    - Formalize design criteria (technical invariants)
-    - Well-defined architecture of isolated components
-        - Swappable store
-          - Formalize store protocol
-        - Swappable Nix language evaluator
-        - Swappable scheduler and remote-build system
-            - Integrate Hydra (modulo UI) into Nix
-            - Remote protocol speed and reliability improvements
-            - Binary cache protocol speed improvements
-
-    - Minimal custom code base (proven off-the-shelf components where possible)
-      - Git file hashing
-      - Sandboxing, containers
-      - Capnproto for RPC
-      - Bazel RBE protocol
-      - ...

scripts/check-hydra-status.sh

@@ -14,7 +14,7 @@ curl -sS -H 'Accept: application/json' https://hydra.nixos.org/jobset/nix/master
 someBuildFailed=0
 
 for buildId in $BUILDS_FOR_LATEST_EVAL; do
-  buildInfo=$(curl --fail -sS -H 'Accept: application/json' "https://hydra.nixos.org/build/$buildId")
+  buildInfo=$(curl -sS -H 'Accept: application/json' "https://hydra.nixos.org/build/$buildId")
 
   finished=$(echo "$buildInfo" | jq -r '.finished')
 

scripts/create-darwin-volume.sh

@@ -442,14 +442,9 @@ add_nix_vol_fstab_line() {
     local escaped_mountpoint="${NIX_ROOT/ /'\\\'040}"
     shift
 
-    # wrap `ex` to work around problems w/ vim features breaking exit codes
-    # - plugins (see github.com/NixOS/nix/issues/5468): -u NONE
-    # - swap file: -n
-    #
-    # the first draft used `--noplugin`, but github.com/NixOS/nix/issues/6462
-    # suggests we need the less-semantic `-u NONE`
-    #
-    # we'd prefer EDITOR="/usr/bin/ex -u NONE" but vifs doesn't word-split
+    # wrap `ex` to work around a problem with vim plugins breaking exit codes;
+    # (see https://github.com/NixOS/nix/issues/5468)
+    # we'd prefer EDITOR="/usr/bin/ex --noplugin" but vifs doesn't word-split
     # the EDITOR env.
     #
     # TODO: at some point we should switch to `--clean`, but it wasn't added
@@ -457,7 +452,7 @@ add_nix_vol_fstab_line() {
     # minver 10.12.6 seems to have released with vim 7.4
     cat > "$SCRATCH/ex_cleanroom_wrapper" <<EOF
 #!/bin/sh
-/usr/bin/ex -u NONE -n "\$@"
+/usr/bin/ex --noplugin "\$@"
 EOF
     chmod 755 "$SCRATCH/ex_cleanroom_wrapper"
 
@@ -651,9 +646,8 @@ EOF
         task "Configuring /etc/synthetic.conf to make a mount-point at $NIX_ROOT" >&2
         # technically /etc/synthetic.d/nix is supported in Big Sur+
         # but handling both takes even more code...
-        # See earlier note; `-u NONE` disables vim plugins/rc, `-n` skips swapfile
         _sudo "to add Nix to /etc/synthetic.conf" \
-            /usr/bin/ex -u NONE -n /etc/synthetic.conf <<EOF
+            /usr/bin/ex --noplugin /etc/synthetic.conf <<EOF
 :a
 ${NIX_ROOT:1}
 .
@@ -821,8 +815,7 @@ setup_volume_daemon() {
     local volume_uuid="$2"
     if ! test_voldaemon; then
         task "Configuring LaunchDaemon to mount '$NIX_VOLUME_LABEL'" >&2
-        # See earlier note; `-u NONE` disables vim plugins/rc, `-n` skips swapfile
-        _sudo "to install the Nix volume mounter" /usr/bin/ex -u NONE -n "$NIX_VOLUME_MOUNTD_DEST" <<EOF
+        _sudo "to install the Nix volume mounter" /usr/bin/ex --noplugin "$NIX_VOLUME_MOUNTD_DEST" <<EOF
 :a
 $(generate_mount_daemon "$cmd_type" "$volume_uuid")
 .

scripts/install-darwin-multi-user.sh

@@ -167,7 +167,7 @@ poly_user_shell_get() {
 }
 
 poly_user_shell_set() {
-    _sudo "in order to give $1 a safe shell" \
+    _sudo "in order to give $1 a safe home directory" \
           /usr/bin/dscl . -create "/Users/$1" "UserShell" "$2"
 }
 

scripts/install-multi-user.sh

@@ -37,19 +37,6 @@ readonly PROFILE_TARGETS=("/etc/bashrc" "/etc/profile.d/nix.sh" "/etc/zshrc" "/e
 readonly PROFILE_BACKUP_SUFFIX=".backup-before-nix"
 readonly PROFILE_NIX_FILE="$NIX_ROOT/var/nix/profiles/default/etc/profile.d/nix-daemon.sh"
 
-# Fish has different syntax than zsh/bash, treat it separate
-readonly PROFILE_FISH_SUFFIX="conf.d/nix.fish"
-readonly PROFILE_FISH_PREFIXES=(
-    # each of these are common values of $__fish_sysconf_dir,
-    # under which Fish will look for a file named
-    # $PROFILE_FISH_SUFFIX.
-    "/etc/fish"              # standard
-    "/usr/local/etc/fish"    # their installer .pkg for macOS
-    "/opt/homebrew/etc/fish" # homebrew
-    "/opt/local/etc/fish"    # macports
-)
-readonly PROFILE_NIX_FILE_FISH="$NIX_ROOT/var/nix/profiles/default/etc/profile.d/nix-daemon.fish"
-
 readonly NIX_INSTALLED_NIX="@nix@"
 readonly NIX_INSTALLED_CACERT="@cacert@"
 #readonly NIX_INSTALLED_NIX="/nix/store/j8dbv5w6jl34caywh2ygdy88knx1mdf7-nix-2.3.6"
@@ -72,30 +59,6 @@ headless() {
     fi
 }
 
-is_root() {
-    if [ "$EUID" -eq 0 ]; then
-        return 0
-    else
-        return 1
-    fi
-}
-
-is_os_linux() {
-    if [ "$(uname -s)" = "Linux" ]; then
-        return 0
-    else
-        return 1
-    fi
-}
-
-is_os_darwin() {
-    if [ "$(uname -s)" = "Darwin" ]; then
-        return 0
-    else
-        return 1
-    fi
-}
-
 contact_us() {
     echo "You can open an issue at https://github.com/nixos/nix/issues"
     echo ""
@@ -350,23 +313,14 @@ __sudo() {
 _sudo() {
     local expl="$1"
     shift
-    if ! headless || is_root; then
+    if ! headless; then
         __sudo "$expl" "$*" >&2
     fi
-
-    if is_root; then
-        env "$@"
-    else
-        sudo "$@"
-    fi
+    sudo "$@"
 }
 
-# Ensure that $TMPDIR exists if defined.
-if [[ -n "${TMPDIR:-}" ]] && [[ ! -d "${TMPDIR:-}" ]]; then
-    mkdir -m 0700 -p "${TMPDIR:-}"
-fi
 
-readonly SCRATCH=$(mktemp -d)
+readonly SCRATCH=$(mktemp -d "${TMPDIR:-/tmp/}tmp.XXXXXXXXXX")
 finish_cleanup() {
     rm -rf "$SCRATCH"
 }
@@ -375,7 +329,7 @@ finish_fail() {
     finish_cleanup
 
     failure <<EOF
-Oh no, something went wrong. If you can take all the output and open
+Jeeze, something went wrong. If you can take all the output and open
 an issue, we'd love to fix the problem so nobody else has this issue.
 
 :(
@@ -469,18 +423,6 @@ EOF
         fi
     done
 
-    if is_os_linux && [ ! -e /run/systemd/system ]; then
-        warning <<EOF
-We did not detect systemd on your system. With a multi-user install
-without systemd you will have to manually configure your init system to
-launch the Nix daemon after installation.
-EOF
-        if ! ui_confirm "Do you want to proceed with a multi-user installation?"; then
-            failure <<EOF
-You have aborted the installation.
-EOF
-        fi
-    fi
 }
 
 setup_report() {
@@ -684,17 +626,6 @@ place_channel_configuration() {
     fi
 }
 
-check_selinux() {
-    if command -v getenforce > /dev/null 2>&1; then
-        if [ "$(getenforce)" = "Enforcing" ]; then
-            failure <<EOF
-Nix does not work with selinux enabled yet!
-see https://github.com/NixOS/nix/issues/2374
-EOF
-        fi
-    fi
-}
-
 welcome_to_nix() {
     ok "Welcome to the Multi-User Nix Installation"
 
@@ -808,7 +739,7 @@ install_from_extracted_nix() {
         cd "$EXTRACTED_NIX_PATH"
 
         _sudo "to copy the basic Nix files to the new store at $NIX_ROOT/store" \
-              cp -RPp ./store/* "$NIX_ROOT/store/"
+              cp -RLp ./store/* "$NIX_ROOT/store/"
 
         _sudo "to make the new store non-writable at $NIX_ROOT/store" \
               chmod -R ugo-w "$NIX_ROOT/store/"
@@ -823,7 +754,7 @@ EOF
         fi
 
         _sudo "to load data for the first time in to the Nix Database" \
-              HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-store" --load-db < ./.reginfo
+              "$NIX_INSTALLED_NIX/bin/nix-store" --load-db < ./.reginfo
 
         echo "      Just finished getting the nix database ready."
     )
@@ -841,19 +772,6 @@ fi
 EOF
 }
 
-# Fish has differing syntax
-fish_source_lines() {
-    cat <<EOF
-
-# Nix
-if test -e '$PROFILE_NIX_FILE_FISH'
-  . '$PROFILE_NIX_FILE_FISH'
-end
-# End Nix
-
-EOF
-}
-
 configure_shell_profile() {
     task "Setting up shell profiles: ${PROFILE_TARGETS[*]}"
     for profile_target in "${PROFILE_TARGETS[@]}"; do
@@ -875,27 +793,6 @@ configure_shell_profile() {
                         tee -a "$profile_target"
         fi
     done
-
-    task "Setting up shell profiles for Fish with with ${PROFILE_FISH_SUFFIX} inside ${PROFILE_FISH_PREFIXES[*]}"
-    for fish_prefix in "${PROFILE_FISH_PREFIXES[@]}"; do
-        if [ ! -d "$fish_prefix" ]; then
-            # this specific prefix (ie: /etc/fish) is very likely to exist
-            # if Fish is installed with this sysconfdir.
-            continue
-        fi
-
-        profile_target="${fish_prefix}/${PROFILE_FISH_SUFFIX}"
-        conf_dir=$(dirname "$profile_target")
-        if [ ! -d "$conf_dir" ]; then
-            _sudo "create $conf_dir for our Fish hook" \
-                mkdir "$conf_dir"
-        fi
-
-        fish_source_lines \
-            | _sudo "write nix-daemon settings to $profile_target" \
-                    tee "$profile_target"
-    done
-
     # TODO: should we suggest '. $PROFILE_NIX_FILE'? It would get them on
     # their way less disruptively, but a counter-argument is that they won't
     # immediately notice if something didn't get set up right?
@@ -945,14 +842,22 @@ EOF
           install -m 0664 "$SCRATCH/nix.conf" /etc/nix/nix.conf
 }
 
-
 main() {
-    check_selinux
+    # TODO: I've moved this out of validate_starting_assumptions so we
+    # can fail faster in this case. Sourcing install-darwin... now runs
+    # `touch /` to detect Read-only root, but it could update times on
+    # pre-Catalina macOS if run as root user.
+    if [ "$EUID" -eq 0 ]; then
+        failure <<EOF
+Please do not run this script with root privileges. I will call sudo
+when I need to.
+EOF
+    fi
 
-    if is_os_darwin; then
+    if [ "$(uname -s)" = "Darwin" ]; then
         # shellcheck source=./install-darwin-multi-user.sh
         . "$EXTRACTED_NIX_PATH/install-darwin-multi-user.sh"
-    elif is_os_linux; then
+    elif [ "$(uname -s)" = "Linux" ]; then
         # shellcheck source=./install-systemd-multi-user.sh
         . "$EXTRACTED_NIX_PATH/install-systemd-multi-user.sh" # most of this works on non-systemd distros also
     else
@@ -960,10 +865,7 @@ main() {
     fi
 
     welcome_to_nix
-
-    if ! is_root; then
-        chat_about_sudo
-    fi
+    chat_about_sudo
 
     cure_artifacts
     # TODO: there's a tension between cure and validate. I moved the

scripts/install-nix-from-closure.sh

@@ -148,9 +148,7 @@ if ! [ -w "$dest" ]; then
     exit 1
 fi
 
-# The auto-chroot code in openFromNonUri() checks for the
-# non-existence of /nix/var/nix, so we need to create it here.
-mkdir -p "$dest/store" "$dest/var/nix"
+mkdir -p "$dest/store"
 
 printf "copying Nix to %s..." "${dest}/store" >&2
 # Insert a newline if no progress is shown.
@@ -209,50 +207,31 @@ if [ -z "$NIX_INSTALLER_NO_CHANNEL_ADD" ]; then
 fi
 
 added=
-p=
-p_sh=$HOME/.nix-profile/etc/profile.d/nix.sh
-p_fish=$HOME/.nix-profile/etc/profile.d/nix.fish
+p=$HOME/.nix-profile/etc/profile.d/nix.sh
 if [ -z "$NIX_INSTALLER_NO_MODIFY_PROFILE" ]; then
     # Make the shell source nix.sh during login.
     for i in .bash_profile .bash_login .profile; do
         fn="$HOME/$i"
         if [ -w "$fn" ]; then
-            if ! grep -q "$p_sh" "$fn"; then
+            if ! grep -q "$p" "$fn"; then
                 echo "modifying $fn..." >&2
-                printf '\nif [ -e %s ]; then . %s; fi # added by Nix installer\n' "$p_sh" "$p_sh" >> "$fn"
+                printf '\nif [ -e %s ]; then . %s; fi # added by Nix installer\n' "$p" "$p" >> "$fn"
             fi
             added=1
-            p=${p_sh}
             break
         fi
     done
     for i in .zshenv .zshrc; do
         fn="$HOME/$i"
         if [ -w "$fn" ]; then
-            if ! grep -q "$p_sh" "$fn"; then
+            if ! grep -q "$p" "$fn"; then
                 echo "modifying $fn..." >&2
-                printf '\nif [ -e %s ]; then . %s; fi # added by Nix installer\n' "$p_sh" "$p_sh" >> "$fn"
+                printf '\nif [ -e %s ]; then . %s; fi # added by Nix installer\n' "$p" "$p" >> "$fn"
             fi
             added=1
-            p=${p_sh}
             break
         fi
     done
-
-    if [ -d "$HOME/.config/fish" ]; then
-        fishdir=$HOME/.config/fish/conf.d
-        if [ ! -d "$fishdir" ]; then
-            mkdir -p "$fishdir"
-        fi
-
-        fn="$fishdir/nix.fish"
-        echo "placing $fn..." >&2
-        printf '\nif test -e %s; . %s; end # added by Nix installer\n' "$p_fish" "$p_fish" > "$fn"
-        added=1
-        p=${p_fish}
-    fi
-else
-    p=${p_sh}
 fi
 
 if [ -z "$added" ]; then

scripts/install-systemd-multi-user.sh

@@ -9,8 +9,6 @@ readonly SERVICE_DEST=/etc/systemd/system/nix-daemon.service
 readonly SOCKET_SRC=/lib/systemd/system/nix-daemon.socket
 readonly SOCKET_DEST=/etc/systemd/system/nix-daemon.socket
 
-readonly TMPFILES_SRC=/lib/tmpfiles.d/nix-daemon.conf
-readonly TMPFILES_DEST=/etc/tmpfiles.d/nix-daemon.conf
 
 # Path for the systemd override unit file to contain the proxy settings
 readonly SERVICE_OVERRIDE=${SERVICE_DEST}.d/override.conf
@@ -85,13 +83,6 @@ EOF
 poly_configure_nix_daemon_service() {
     if [ -e /run/systemd/system ]; then
         task "Setting up the nix-daemon systemd service"
-
-        _sudo "to create the nix-daemon tmpfiles config" \
-              ln -sfn /nix/var/nix/profiles/default/$TMPFILES_SRC $TMPFILES_DEST
-
-        _sudo "to run systemd-tmpfiles once to pick that path up" \
-             systemd-tmpfiles --create --prefix=/nix/var/nix
-
         _sudo "to set up the nix-daemon service" \
               systemctl link "/nix/var/nix/profiles/default$SERVICE_SRC"
 

scripts/install.in

@@ -40,12 +40,12 @@ case "$(uname -s).$(uname -m)" in
         path=@tarballPath_aarch64-linux@
         system=aarch64-linux
         ;;
-    Linux.armv6l)
+    Linux.armv6l_linux)
         hash=@tarballHash_armv6l-linux@
         path=@tarballPath_armv6l-linux@
         system=armv6l-linux
         ;;
-    Linux.armv7l)
+    Linux.armv7l_linux)
         hash=@tarballHash_armv7l-linux@
         path=@tarballPath_armv7l-linux@
         system=armv7l-linux
@@ -82,7 +82,7 @@ if [ "$(uname -s)" != "Darwin" ]; then
 fi
 
 if command -v curl > /dev/null 2>&1; then
-    fetch() { curl --fail -L "$1" -o "$2"; }
+    fetch() { curl -L "$1" -o "$2"; }
 elif command -v wget > /dev/null 2>&1; then
     fetch() { wget "$1" -O "$2"; }
 else

scripts/local.mk

@@ -6,8 +6,6 @@ noinst-scripts += $(nix_noinst_scripts)
 profiledir = $(sysconfdir)/profile.d
 
 $(eval $(call install-file-as, $(d)/nix-profile.sh, $(profiledir)/nix.sh, 0644))
-$(eval $(call install-file-as, $(d)/nix-profile.fish, $(profiledir)/nix.fish, 0644))
 $(eval $(call install-file-as, $(d)/nix-profile-daemon.sh, $(profiledir)/nix-daemon.sh, 0644))
-$(eval $(call install-file-as, $(d)/nix-profile-daemon.fish, $(profiledir)/nix-daemon.fish, 0644))
 
 clean-files += $(nix_noinst_scripts)

scripts/nix-profile-daemon.fish.in

@@ -1,35 +0,0 @@
-# Only execute this file once per shell.
-if test -n "$__ETC_PROFILE_NIX_SOURCED"
-  exit
-end
-
-set __ETC_PROFILE_NIX_SOURCED 1
-
-set --export NIX_PROFILES "@localstatedir@/nix/profiles/default $HOME/.nix-profile"
-
-# Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
-if test -n "$NIX_SSH_CERT_FILE"
-  : # Allow users to override the NIX_SSL_CERT_FILE
-else if test -e /etc/ssl/certs/ca-certificates.crt # NixOS, Ubuntu, Debian, Gentoo, Arch
-  set --export NIX_SSL_CERT_FILE /etc/ssl/certs/ca-certificates.crt
-else if test -e /etc/ssl/ca-bundle.pem # openSUSE Tumbleweed
-  set --export NIX_SSL_CERT_FILE /etc/ssl/ca-bundle.pem
-else if test -e /etc/ssl/certs/ca-bundle.crt # Old NixOS
-  set --export NIX_SSL_CERT_FILE /etc/ssl/certs/ca-bundle.crt
-else if test -e /etc/pki/tls/certs/ca-bundle.crt # Fedora, CentOS
-  set --export NIX_SSL_CERT_FILE /etc/pki/tls/certs/ca-bundle.crt
-else if test -e "$NIX_LINK/etc/ssl/certs/ca-bundle.crt" # fall back to cacert in Nix profile
-  set --export NIX_SSL_CERT_FILE "$NIX_LINK/etc/ssl/certs/ca-bundle.crt"
-else if test -e "$NIX_LINK/etc/ca-bundle.crt" # old cacert in Nix profile
-  set --export NIX_SSL_CERT_FILE "$NIX_LINK/etc/ca-bundle.crt"
-else
-  # Fall back to what is in the nix profiles, favouring whatever is defined last.
-  for i in $NIX_PROFILES
-    if test -e "$i/etc/ssl/certs/ca-bundle.crt"
-      set --export NIX_SSL_CERT_FILE "$i/etc/ssl/certs/ca-bundle.crt"
-    end
-  end
-end
-
-fish_add_path --prepend --global "@localstatedir@/nix/profiles/default/bin"
-fish_add_path --prepend --global "$HOME/.nix-profile/bin"

scripts/nix-profile.fish.in

@@ -1,35 +0,0 @@
-if test -n "$HOME" && test -n "$USER"
-
-    # Set up the per-user profile.
-
-    set NIX_LINK $HOME/.nix-profile
-
-    # Set up environment.
-    # This part should be kept in sync with nixpkgs:nixos/modules/programs/environment.nix
-    set --export NIX_PROFILES "@localstatedir@/nix/profiles/default $HOME/.nix-profile"
-
-    # Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
-    if test -n "$NIX_SSH_CERT_FILE"
-        : # Allow users to override the NIX_SSL_CERT_FILE
-    else if test -e /etc/ssl/certs/ca-certificates.crt # NixOS, Ubuntu, Debian, Gentoo, Arch
-        set --export NIX_SSL_CERT_FILE /etc/ssl/certs/ca-certificates.crt
-    else if test -e /etc/ssl/ca-bundle.pem # openSUSE Tumbleweed
-        set --export NIX_SSL_CERT_FILE /etc/ssl/ca-bundle.pem
-    else if test -e /etc/ssl/certs/ca-bundle.crt # Old NixOS
-        set --export NIX_SSL_CERT_FILE /etc/ssl/certs/ca-bundle.crt
-    else if test -e /etc/pki/tls/certs/ca-bundle.crt # Fedora, CentOS
-        set --export NIX_SSL_CERT_FILE /etc/pki/tls/certs/ca-bundle.crt
-    else if test -e "$NIX_LINK/etc/ssl/certs/ca-bundle.crt" # fall back to cacert in Nix profile
-        set --export NIX_SSL_CERT_FILE "$NIX_LINK/etc/ssl/certs/ca-bundle.crt"
-    else if test -e "$NIX_LINK/etc/ca-bundle.crt" # old cacert in Nix profile
-        set --export NIX_SSL_CERT_FILE "$NIX_LINK/etc/ca-bundle.crt"
-    end
-
-    # Only use MANPATH if it is already set. In general `man` will just simply
-    # pick up `.nix-profile/share/man` because is it close to `.nix-profile/bin`
-    # which is in the $PATH. For more info, run `manpath -d`.
-    set --export --prepend --path MANPATH "$NIX_LINK/share/man"
-
-    fish_add_path --prepend --global "$NIX_LINK/bin"
-    set --erase NIX_LINK
-end

scripts/nix-profile.sh.in

@@ -1,6 +1,7 @@
 if [ -n "$HOME" ] && [ -n "$USER" ]; then
 
     # Set up the per-user profile.
+    # This part should be kept in sync with nixpkgs:nixos/modules/programs/shell.nix
 
     NIX_LINK=$HOME/.nix-profile
 

src/build-remote/build-remote.cc

@@ -300,7 +300,7 @@ connected:
 
         std::set<Realisation> missingRealisations;
         StorePathSet missingPaths;
-        if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations) && !drv.type().hasKnownOutputPaths()) {
+        if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations) && !derivationHasKnownOutputPaths(drv.type())) {
             for (auto & outputName : wantedOutputs) {
                 auto thisOutputHash = outputHashes.at(outputName);
                 auto thisOutputId = DrvOutput{ thisOutputHash, outputName };

src/libcmd/command.cc

@@ -86,11 +86,6 @@ ref<Store> CopyCommand::getDstStore()
 
 EvalCommand::EvalCommand()
 {
-    addFlag({
-        .longName = "debugger",
-        .description = "start an interactive environment if evaluation fails",
-        .handler = {&startReplOnEvalErrors, true},
-    });
 }
 
 EvalCommand::~EvalCommand()
@@ -108,7 +103,7 @@ ref<Store> EvalCommand::getEvalStore()
 
 ref<EvalState> EvalCommand::getEvalState()
 {
-    if (!evalState) {
+    if (!evalState)
         evalState =
             #if HAVE_BOEHMGC
             std::allocate_shared<EvalState>(traceable_allocator<EvalState>(),
@@ -118,11 +113,6 @@ ref<EvalState> EvalCommand::getEvalState()
                 searchPath, getEvalStore(), getStore())
             #endif
             ;
-
-        if (startReplOnEvalErrors) {
-            evalState->debugRepl = &runRepl;
-        };
-    }
     return ref<EvalState>(evalState);
 }
 
@@ -207,17 +197,16 @@ void StorePathCommand::run(ref<Store> store, std::vector<StorePath> && storePath
     run(store, *storePaths.begin());
 }
 
-Strings editorFor(const Path & file, uint32_t line)
+Strings editorFor(const Pos & pos)
 {
     auto editor = getEnv("EDITOR").value_or("cat");
     auto args = tokenizeString<Strings>(editor);
-    if (line > 0 && (
+    if (pos.line > 0 && (
         editor.find("emacs") != std::string::npos ||
         editor.find("nano") != std::string::npos ||
-        editor.find("vim") != std::string::npos ||
-        editor.find("kak") != std::string::npos))
-        args.push_back(fmt("+%d", line));
-    args.push_back(file);
+        editor.find("vim") != std::string::npos))
+        args.push_back(fmt("+%d", pos.line));
+    args.push_back(pos.file);
     return args;
 }
 

src/libcmd/command.hh

@@ -57,9 +57,6 @@ struct CopyCommand : virtual StoreCommand
 
 struct EvalCommand : virtual StoreCommand, MixEvalArgs
 {
-    bool startReplOnEvalErrors = false;
-    bool ignoreExceptionsDuringTry = false;
-
     EvalCommand();
 
     ~EvalCommand();
@@ -78,28 +75,21 @@ struct MixFlakeOptions : virtual Args, EvalCommand
 {
     flake::LockFlags lockFlags;
 
-    std::optional<std::string> needsFlakeInputCompletion = {};
-
     MixFlakeOptions();
 
-    virtual std::vector<std::string> getFlakesForCompletion()
+    virtual std::optional<FlakeRef> getFlakeRefForCompletion()
     { return {}; }
-
-    void completeFlakeInput(std::string_view prefix);
-
-    void completionHook() override;
 };
 
 struct SourceExprCommand : virtual Args, MixFlakeOptions
 {
     std::optional<Path> file;
     std::optional<std::string> expr;
-    bool readOnlyMode = false;
 
     // FIXME: move this; not all commands (e.g. 'nix run') use it.
     OperateOn operateOn = OperateOn::Output;
 
-    SourceExprCommand(bool supportReadOnlyMode = false);
+    SourceExprCommand();
 
     std::vector<std::shared_ptr<Installable>> parseInstallables(
         ref<Store> store, std::vector<std::string> ss);
@@ -123,13 +113,12 @@ struct InstallablesCommand : virtual Args, SourceExprCommand
     InstallablesCommand();
 
     void prepare() override;
-    Installables load();
 
     virtual bool useDefaultInstallables() { return true; }
 
-    std::vector<std::string> getFlakesForCompletion() override;
+    std::optional<FlakeRef> getFlakeRefForCompletion() override;
 
-protected:
+private:
 
     std::vector<std::string> _installables;
 };
@@ -139,13 +128,13 @@ struct InstallableCommand : virtual Args, SourceExprCommand
 {
     std::shared_ptr<Installable> installable;
 
-    InstallableCommand(bool supportReadOnlyMode = false);
+    InstallableCommand();
 
     void prepare() override;
 
-    std::vector<std::string> getFlakesForCompletion() override
+    std::optional<FlakeRef> getFlakeRefForCompletion() override
     {
-        return {_installable};
+        return parseFlakeRef(_installable, absPath("."));
     }
 
 private:
@@ -229,7 +218,7 @@ static RegisterCommand registerCommand2(std::vector<std::string> && name)
 
 /* Helper function to generate args that invoke $EDITOR on
    filename:lineno. */
-Strings editorFor(const Path & file, uint32_t line);
+Strings editorFor(const Pos & pos);
 
 struct MixProfile : virtual StoreCommand
 {
@@ -280,8 +269,4 @@ void printClosureDiff(
     const StorePath & afterPath,
     std::string_view indent);
 
-
-void runRepl(
-    ref<EvalState> evalState,
-    const ValMap & extraEnv);
 }

src/libcmd/installables.cc

@@ -1,6 +1,4 @@
-#include "globals.hh"
 #include "installables.hh"
-#include "util.hh"
 #include "command.hh"
 #include "attr-path.hh"
 #include "common-eval-args.hh"
@@ -14,7 +12,6 @@
 #include "eval-cache.hh"
 #include "url.hh"
 #include "registry.hh"
-#include "build-result.hh"
 
 #include <regex>
 #include <queue>
@@ -23,6 +20,17 @@
 
 namespace nix {
 
+void completeFlakeInputPath(
+    ref<EvalState> evalState,
+    const FlakeRef & flakeRef,
+    std::string_view prefix)
+{
+    auto flake = flake::getFlake(*evalState, flakeRef, true);
+    for (auto & input : flake.inputs)
+        if (hasPrefix(input.first, prefix))
+            completions->add(input.first);
+}
+
 MixFlakeOptions::MixFlakeOptions()
 {
     auto category = "Common flake-related options";
@@ -75,7 +83,8 @@ MixFlakeOptions::MixFlakeOptions()
             lockFlags.inputUpdates.insert(flake::parseInputPath(s));
         }},
         .completer = {[&](size_t, std::string_view prefix) {
-            needsFlakeInputCompletion = {std::string(prefix)};
+            if (auto flakeRef = getFlakeRefForCompletion())
+                completeFlakeInputPath(getEvalState(), *flakeRef, prefix);
         }}
     });
 
@@ -89,12 +98,6 @@ MixFlakeOptions::MixFlakeOptions()
             lockFlags.inputOverrides.insert_or_assign(
                 flake::parseInputPath(inputPath),
                 parseFlakeRef(flakeRef, absPath("."), true));
-        }},
-        .completer = {[&](size_t n, std::string_view prefix) {
-            if (n == 0)
-                needsFlakeInputCompletion = {std::string(prefix)};
-            else if (n == 1)
-                completeFlakeRef(getEvalState()->store, prefix);
         }}
     });
 
@@ -125,33 +128,12 @@ MixFlakeOptions::MixFlakeOptions()
     });
 }
 
-void MixFlakeOptions::completeFlakeInput(std::string_view prefix)
-{
-    auto evalState = getEvalState();
-    for (auto & flakeRefS : getFlakesForCompletion()) {
-        auto flakeRef = parseFlakeRefWithFragment(expandTilde(flakeRefS), absPath(".")).first;
-        auto flake = flake::getFlake(*evalState, flakeRef, true);
-        for (auto & input : flake.inputs)
-            if (hasPrefix(input.first, prefix))
-                completions->add(input.first);
-    }
-}
-
-void MixFlakeOptions::completionHook()
-{
-    if (auto & prefix = needsFlakeInputCompletion)
-        completeFlakeInput(*prefix);
-}
-
-SourceExprCommand::SourceExprCommand(bool supportReadOnlyMode)
+SourceExprCommand::SourceExprCommand()
 {
     addFlag({
         .longName = "file",
         .shortName = 'f',
-        .description =
-            "Interpret installables as attribute paths relative to the Nix expression stored in *file*. "
-            "If *file* is the character -, then a Nix expression will be read from standard input. "
-            "Implies `--impure`.",
+        .description = "Interpret installables as attribute paths relative to the Nix expression stored in *file*.",
         .category = installablesCategory,
         .labels = {"file"},
         .handler = {&file},
@@ -172,17 +154,6 @@ SourceExprCommand::SourceExprCommand(bool supportReadOnlyMode)
         .category = installablesCategory,
         .handler = {&operateOn, OperateOn::Derivation},
     });
-
-    if (supportReadOnlyMode) {
-        addFlag({
-            .longName = "read-only",
-            .description =
-                "Do not instantiate each evaluated derivation. "
-                "This improves performance, but can cause errors when accessing "
-                "store paths of derivations during evaluation.",
-            .handler = {&readOnlyMode, true},
-        });
-    }
 }
 
 Strings SourceExprCommand::getDefaultFlakeAttrPaths()
@@ -208,8 +179,6 @@ Strings SourceExprCommand::getDefaultFlakeAttrPathPrefixes()
 void SourceExprCommand::completeInstallable(std::string_view prefix)
 {
     if (file) {
-        completionType = ctAttrs;
-
         evalSettings.pureEval = false;
         auto state = getEvalState();
         Expr *e = state->parseExprFromFile(
@@ -238,14 +207,13 @@ void SourceExprCommand::completeInstallable(std::string_view prefix)
         Value v2;
         state->autoCallFunction(*autoArgs, v1, v2);
 
+        completionType = ctAttrs;
+
         if (v2.type() == nAttrs) {
             for (auto & i : *v2.attrs) {
-                std::string name = state->symbols[i.name];
+                std::string name = i.name;
                 if (name.find(searchWord) == 0) {
-                    if (prefix_ == "")
-                        completions->add(name);
-                    else
-                        completions->add(prefix_ + "." + name);
+                    completions->add(i.name);
                 }
             }
         }
@@ -273,11 +241,10 @@ void completeFlakeRefWithFragment(
         if (hash == std::string::npos) {
             completeFlakeRef(evalState->store, prefix);
         } else {
-            completionType = ctAttrs;
-
             auto fragment = prefix.substr(hash + 1);
             auto flakeRefS = std::string(prefix.substr(0, hash));
-            auto flakeRef = parseFlakeRef(expandTilde(flakeRefS), absPath("."));
+            // FIXME: do tilde expansion.
+            auto flakeRef = parseFlakeRef(flakeRefS, absPath("."));
 
             auto evalCache = openEvalCache(*evalState,
                 std::make_shared<flake::LockedFlake>(lockFlake(*evalState, flakeRef, lockFlags)));
@@ -289,6 +256,8 @@ void completeFlakeRefWithFragment(
                flake. */
             attrPathPrefixes.push_back("");
 
+            completionType = ctAttrs;
+
             for (auto & attrPathPrefixS : attrPathPrefixes) {
                 auto attrPathPrefix = parseAttrPath(*evalState, attrPathPrefixS);
                 auto attrPathS = attrPathPrefixS + std::string(fragment);
@@ -296,7 +265,7 @@ void completeFlakeRefWithFragment(
 
                 std::string lastAttr;
                 if (!attrPath.empty() && !hasSuffix(attrPathS, ".")) {
-                    lastAttr = evalState->symbols[attrPath.back()];
+                    lastAttr = attrPath.back();
                     attrPath.pop_back();
                 }
 
@@ -304,11 +273,11 @@ void completeFlakeRefWithFragment(
                 if (!attr) continue;
 
                 for (auto & attr2 : (*attr)->getAttrs()) {
-                    if (hasPrefix(evalState->symbols[attr2], lastAttr)) {
+                    if (hasPrefix(attr2, lastAttr)) {
                         auto attrPath2 = (*attr)->getAttrPath(attr2);
                         /* Strip the attrpath prefix. */
                         attrPath2.erase(attrPath2.begin(), attrPath2.begin() + attrPathPrefix.size());
-                        completions->add(flakeRefS + "#" + concatStringsSep(".", evalState->symbols.resolve(attrPath2)));
+                        completions->add(flakeRefS + "#" + concatStringsSep(".", attrPath2));
                     }
                 }
             }
@@ -362,16 +331,16 @@ DerivedPath Installable::toDerivedPath()
     return std::move(buildables[0]);
 }
 
-std::vector<ref<eval_cache::AttrCursor>>
+std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>>
 Installable::getCursors(EvalState & state)
 {
     auto evalCache =
         std::make_shared<nix::eval_cache::EvalCache>(std::nullopt, state,
             [&]() { return toValue(state).first; });
-    return {evalCache->getRoot()};
+    return {{evalCache->getRoot(), ""}};
 }
 
-ref<eval_cache::AttrCursor>
+std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>
 Installable::getCursor(EvalState & state)
 {
     auto cursors = getCursors(state);
@@ -445,8 +414,10 @@ DerivedPaths InstallableValue::toDerivedPaths()
 
     // Group by derivation, helps with .all in particular
     for (auto & drv : toDerivations()) {
-        for (auto & outputName : drv.outputsToInstall)
-            drvsToOutputs[drv.drvPath].insert(outputName);
+        auto outputName = drv.outputName;
+        if (outputName == "")
+            throw Error("derivation '%s' lacks an 'outputName' attribute", state->store->printStorePath(drv.drvPath));
+        drvsToOutputs[drv.drvPath].insert(outputName);
         drvsToCopy.insert(drv.drvPath);
     }
 
@@ -469,24 +440,14 @@ struct InstallableAttrPath : InstallableValue
     SourceExprCommand & cmd;
     RootValue v;
     std::string attrPath;
-    OutputsSpec outputsSpec;
 
-    InstallableAttrPath(
-        ref<EvalState> state,
-        SourceExprCommand & cmd,
-        Value * v,
-        const std::string & attrPath,
-        OutputsSpec outputsSpec)
-        : InstallableValue(state)
-        , cmd(cmd)
-        , v(allocRootValue(v))
-        , attrPath(attrPath)
-        , outputsSpec(std::move(outputsSpec))
+    InstallableAttrPath(ref<EvalState> state, SourceExprCommand & cmd, Value * v, const std::string & attrPath)
+        : InstallableValue(state), cmd(cmd), v(allocRootValue(v)), attrPath(attrPath)
     { }
 
     std::string what() const override { return attrPath; }
 
-    std::pair<Value *, PosIdx> toValue(EvalState & state) override
+    std::pair<Value *, Pos> toValue(EvalState & state) override
     {
         auto [vRes, pos] = findAlongAttrPath(state, attrPath, *cmd.getAutoArgs(state), **v);
         state.forceValue(*vRes, pos);
@@ -510,19 +471,7 @@ std::vector<InstallableValue::DerivationInfo> InstallableAttrPath::toDerivations
         auto drvPath = drvInfo.queryDrvPath();
         if (!drvPath)
             throw Error("'%s' is not a derivation", what());
-
-        std::set<std::string> outputsToInstall;
-
-        if (auto outputNames = std::get_if<OutputNames>(&outputsSpec))
-            outputsToInstall = *outputNames;
-        else
-            for (auto & output : drvInfo.queryOutputs(false, std::get_if<DefaultOutputs>(&outputsSpec)))
-                outputsToInstall.insert(output.first);
-
-        res.push_back(DerivationInfo {
-            .drvPath = *drvPath,
-            .outputsToInstall = std::move(outputsToInstall)
-        });
+        res.push_back({ *drvPath, drvInfo.queryOutputName() });
     }
 
     return res;
@@ -599,7 +548,6 @@ InstallableFlake::InstallableFlake(
     ref<EvalState> state,
     FlakeRef && flakeRef,
     std::string_view fragment,
-    OutputsSpec outputsSpec,
     Strings attrPaths,
     Strings prefixes,
     const flake::LockFlags & lockFlags)
@@ -607,7 +555,6 @@ InstallableFlake::InstallableFlake(
       flakeRef(flakeRef),
       attrPaths(fragment == "" ? attrPaths : Strings{(std::string) fragment}),
       prefixes(fragment == "" ? Strings{} : prefixes),
-      outputsSpec(std::move(outputsSpec)),
       lockFlags(lockFlags)
 {
     if (cmd && cmd->getAutoArgs(*state)->size())
@@ -616,55 +563,43 @@ InstallableFlake::InstallableFlake(
 
 std::tuple<std::string, FlakeRef, InstallableValue::DerivationInfo> InstallableFlake::toDerivation()
 {
-    Activity act(*logger, lvlTalkative, actUnknown, fmt("evaluating derivation '%s'", what()));
+    auto lockedFlake = getLockedFlake();
 
-    auto attr = getCursor(*state);
+    auto cache = openEvalCache(*state, lockedFlake);
+    auto root = cache->getRoot();
 
-    auto attrPath = attr->getAttrPathStr();
+    Suggestions suggestions;
 
-    if (!attr->isDerivation())
-        throw Error("flake output attribute '%s' is not a derivation", attrPath);
+    for (auto & attrPath : getActualAttrPaths()) {
+        debug("trying flake output attribute '%s'", attrPath);
 
-    auto drvPath = attr->forceDerivation();
+        auto attrOrSuggestions = root->findAlongAttrPath(
+            parseAttrPath(*state, attrPath),
+            true
+        );
 
-    std::set<std::string> outputsToInstall;
-    std::optional<NixInt> priority;
-
-    if (auto aOutputSpecified = attr->maybeGetAttr(state->sOutputSpecified)) {
-        if (aOutputSpecified->getBool()) {
-            if (auto aOutputName = attr->maybeGetAttr("outputName"))
-                outputsToInstall = { aOutputName->getString() };
+        if (!attrOrSuggestions) {
+            suggestions += attrOrSuggestions.getSuggestions();
+            continue;
         }
+
+        auto attr = *attrOrSuggestions;
+
+        if (!attr->isDerivation())
+            throw Error("flake output attribute '%s' is not a derivation", attrPath);
+
+        auto drvPath = attr->forceDerivation();
+
+        auto drvInfo = DerivationInfo {
+            std::move(drvPath),
+            attr->getAttr(state->sOutputName)->getString()
+        };
+
+        return {attrPath, lockedFlake->flake.lockedRef, std::move(drvInfo)};
     }
 
-    else if (auto aMeta = attr->maybeGetAttr(state->sMeta)) {
-        if (auto aOutputsToInstall = aMeta->maybeGetAttr("outputsToInstall"))
-            for (auto & s : aOutputsToInstall->getListOfStrings())
-                outputsToInstall.insert(s);
-        if (auto aPriority = aMeta->maybeGetAttr("priority"))
-            priority = aPriority->getInt();
-    }
-
-    if (outputsToInstall.empty() || std::get_if<AllOutputs>(&outputsSpec)) {
-        outputsToInstall.clear();
-        if (auto aOutputs = attr->maybeGetAttr(state->sOutputs))
-            for (auto & s : aOutputs->getListOfStrings())
-                outputsToInstall.insert(s);
-    }
-
-    if (outputsToInstall.empty())
-        outputsToInstall.insert("out");
-
-    if (auto outputNames = std::get_if<OutputNames>(&outputsSpec))
-        outputsToInstall = *outputNames;
-
-    auto drvInfo = DerivationInfo {
-        .drvPath = std::move(drvPath),
-        .outputsToInstall = std::move(outputsToInstall),
-        .priority = priority,
-    };
-
-    return {attrPath, getLockedFlake()->flake.lockedRef, std::move(drvInfo)};
+    throw Error(suggestions, "flake '%s' does not provide attribute %s",
+        flakeRef, showAttrPaths(getActualAttrPaths()));
 }
 
 std::vector<InstallableValue::DerivationInfo> InstallableFlake::toDerivations()
@@ -674,12 +609,35 @@ std::vector<InstallableValue::DerivationInfo> InstallableFlake::toDerivations()
     return res;
 }
 
-std::pair<Value *, PosIdx> InstallableFlake::toValue(EvalState & state)
+std::pair<Value *, Pos> InstallableFlake::toValue(EvalState & state)
 {
-    return {&getCursor(state)->forceValue(), noPos};
+    auto lockedFlake = getLockedFlake();
+
+    auto vOutputs = getFlakeOutputs(state, *lockedFlake);
+
+    auto emptyArgs = state.allocBindings(0);
+
+    Suggestions suggestions;
+
+    for (auto & attrPath : getActualAttrPaths()) {
+        try {
+            auto [v, pos] = findAlongAttrPath(state, attrPath, *emptyArgs, *vOutputs);
+            state.forceValue(*v, pos);
+            return {v, pos};
+        } catch (AttrPathNotFound & e) {
+            suggestions += e.info().suggestions;
+        }
+    }
+
+    throw Error(
+        suggestions,
+        "flake '%s' does not provide attribute %s",
+        flakeRef,
+        showAttrPaths(getActualAttrPaths())
+    );
 }
 
-std::vector<ref<eval_cache::AttrCursor>>
+std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>>
 InstallableFlake::getCursors(EvalState & state)
 {
     auto evalCache = openEvalCache(state,
@@ -687,55 +645,21 @@ InstallableFlake::getCursors(EvalState & state)
 
     auto root = evalCache->getRoot();
 
-    std::vector<ref<eval_cache::AttrCursor>> res;
+    std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>> res;
 
     for (auto & attrPath : getActualAttrPaths()) {
         auto attr = root->findAlongAttrPath(parseAttrPath(state, attrPath));
-        if (attr) res.push_back(ref(*attr));
+        if (attr) res.push_back({*attr, attrPath});
     }
 
     return res;
 }
 
-ref<eval_cache::AttrCursor> InstallableFlake::getCursor(EvalState & state)
-{
-    auto lockedFlake = getLockedFlake();
-
-    auto cache = openEvalCache(state, lockedFlake);
-    auto root = cache->getRoot();
-
-    Suggestions suggestions;
-
-    auto attrPaths = getActualAttrPaths();
-
-    for (auto & attrPath : attrPaths) {
-        debug("trying flake output attribute '%s'", attrPath);
-
-        auto attrOrSuggestions = root->findAlongAttrPath(
-            parseAttrPath(state, attrPath),
-            true
-        );
-
-        if (!attrOrSuggestions) {
-            suggestions += attrOrSuggestions.getSuggestions();
-            continue;
-        }
-
-        return *attrOrSuggestions;
-    }
-
-    throw Error(
-        suggestions,
-        "flake '%s' does not provide attribute %s",
-        flakeRef,
-        showAttrPaths(attrPaths));
-}
-
 std::shared_ptr<flake::LockedFlake> InstallableFlake::getLockedFlake() const
 {
+    flake::LockFlags lockFlagsApplyConfig = lockFlags;
+    lockFlagsApplyConfig.applyNixConfig = true;
     if (!_lockedFlake) {
-        flake::LockFlags lockFlagsApplyConfig = lockFlags;
-        lockFlagsApplyConfig.applyNixConfig = true;
         _lockedFlake = std::make_shared<flake::LockedFlake>(lockFlake(*state, flakeRef, lockFlagsApplyConfig));
     }
     return _lockedFlake;
@@ -760,10 +684,6 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
 {
     std::vector<std::shared_ptr<Installable>> result;
 
-    if (readOnlyMode) {
-        settings.readOnlyMode = true;
-    }
-
     if (file || expr) {
         if (file && expr)
             throw UsageError("'--file' and '--expr' are exclusive");
@@ -774,24 +694,15 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
         auto state = getEvalState();
         auto vFile = state->allocValue();
 
-        if (file == "-") {
-            auto e = state->parseStdin();
-            state->eval(e, *vFile);
-        } else if (file)
+        if (file)
             state->evalFile(lookupFileArg(*state, *file), *vFile);
         else {
             auto e = state->parseExprFromString(*expr, absPath("."));
             state->eval(e, *vFile);
         }
 
-        for (auto & s : ss) {
-            auto [prefix, outputsSpec] = parseOutputsSpec(s);
-            result.push_back(
-                std::make_shared<InstallableAttrPath>(
-                    state, *this, vFile,
-                    prefix == "." ? "" : prefix,
-                    outputsSpec));
-        }
+        for (auto & s : ss)
+            result.push_back(std::make_shared<InstallableAttrPath>(state, *this, vFile, s == "." ? "" : s));
 
     } else {
 
@@ -810,13 +721,12 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
             }
 
             try {
-                auto [flakeRef, fragment, outputsSpec] = parseFlakeRefWithFragmentAndOutputsSpec(s, absPath("."));
+                auto [flakeRef, fragment] = parseFlakeRefWithFragment(s, absPath("."));
                 result.push_back(std::make_shared<InstallableFlake>(
                         this,
                         getEvalState(),
                         std::move(flakeRef),
                         fragment,
-                        outputsSpec,
                         getDefaultFlakeAttrPaths(),
                         getDefaultFlakeAttrPathPrefixes(),
                         lockFlags));
@@ -840,20 +750,56 @@ std::shared_ptr<Installable> SourceExprCommand::parseInstallable(
     return installables.front();
 }
 
-BuiltPaths Installable::build(
-    ref<Store> evalStore,
-    ref<Store> store,
-    Realise mode,
-    const std::vector<std::shared_ptr<Installable>> & installables,
-    BuildMode bMode)
+BuiltPaths getBuiltPaths(ref<Store> evalStore, ref<Store> store, const DerivedPaths & hopefullyBuiltPaths)
 {
     BuiltPaths res;
-    for (auto & [_, builtPath] : build2(evalStore, store, mode, installables, bMode))
-        res.push_back(builtPath);
+    for (const auto & b : hopefullyBuiltPaths)
+        std::visit(
+            overloaded{
+                [&](const DerivedPath::Opaque & bo) {
+                    res.push_back(BuiltPath::Opaque{bo.path});
+                },
+                [&](const DerivedPath::Built & bfd) {
+                    OutputPathMap outputs;
+                    auto drv = evalStore->readDerivation(bfd.drvPath);
+                    auto outputHashes = staticOutputHashes(*evalStore, drv); // FIXME: expensive
+                    auto drvOutputs = drv.outputsAndOptPaths(*store);
+                    for (auto & output : bfd.outputs) {
+                        if (!outputHashes.count(output))
+                            throw Error(
+                                "the derivation '%s' doesn't have an output named '%s'",
+                                store->printStorePath(bfd.drvPath), output);
+                        if (settings.isExperimentalFeatureEnabled(
+                                Xp::CaDerivations)) {
+                            auto outputId =
+                                DrvOutput{outputHashes.at(output), output};
+                            auto realisation =
+                                store->queryRealisation(outputId);
+                            if (!realisation)
+                                throw Error(
+                                    "cannot operate on an output of unbuilt "
+                                    "content-addressed derivation '%s'",
+                                    outputId.to_string());
+                            outputs.insert_or_assign(
+                                output, realisation->outPath);
+                        } else {
+                            // If ca-derivations isn't enabled, assume that
+                            // the output path is statically known.
+                            assert(drvOutputs.count(output));
+                            assert(drvOutputs.at(output).second);
+                            outputs.insert_or_assign(
+                                output, *drvOutputs.at(output).second);
+                        }
+                    }
+                    res.push_back(BuiltPath::Built{bfd.drvPath, outputs});
+                },
+            },
+            b.raw());
+
     return res;
 }
 
-std::vector<std::pair<std::shared_ptr<Installable>, BuiltPath>> Installable::build2(
+BuiltPaths Installable::build(
     ref<Store> evalStore,
     ref<Store> store,
     Realise mode,
@@ -864,98 +810,18 @@ std::vector<std::pair<std::shared_ptr<Installable>, BuiltPath>> Installable::bui
         settings.readOnlyMode = true;
 
     std::vector<DerivedPath> pathsToBuild;
-    std::map<DerivedPath, std::vector<std::shared_ptr<Installable>>> backmap;
 
     for (auto & i : installables) {
-        for (auto b : i->toDerivedPaths()) {
-            pathsToBuild.push_back(b);
-            backmap[b].push_back(i);
-        }
+        auto b = i->toDerivedPaths();
+        pathsToBuild.insert(pathsToBuild.end(), b.begin(), b.end());
     }
 
-    std::vector<std::pair<std::shared_ptr<Installable>, BuiltPath>> res;
-
-    switch (mode) {
-
-    case Realise::Nothing:
-    case Realise::Derivation:
+    if (mode == Realise::Nothing || mode == Realise::Derivation)
         printMissing(store, pathsToBuild, lvlError);
+    else if (mode == Realise::Outputs)
+        store->buildPaths(pathsToBuild, bMode, evalStore);
 
-        for (auto & path : pathsToBuild) {
-            for (auto & installable : backmap[path]) {
-                std::visit(overloaded {
-                    [&](const DerivedPath::Built & bfd) {
-                        OutputPathMap outputs;
-                        auto drv = evalStore->readDerivation(bfd.drvPath);
-                        auto outputHashes = staticOutputHashes(*evalStore, drv); // FIXME: expensive
-                        auto drvOutputs = drv.outputsAndOptPaths(*store);
-                        for (auto & output : bfd.outputs) {
-                            auto outputHash = get(outputHashes, output);
-                            if (!outputHash)
-                                throw Error(
-                                    "the derivation '%s' doesn't have an output named '%s'",
-                                    store->printStorePath(bfd.drvPath), output);
-                            if (settings.isExperimentalFeatureEnabled(Xp::CaDerivations)) {
-                                DrvOutput outputId { *outputHash, output };
-                                auto realisation = store->queryRealisation(outputId);
-                                if (!realisation)
-                                    throw Error(
-                                        "cannot operate on an output of the "
-                                        "unbuilt derivation '%s'",
-                                        outputId.to_string());
-                                outputs.insert_or_assign(output, realisation->outPath);
-                            } else {
-                                // If ca-derivations isn't enabled, assume that
-                                // the output path is statically known.
-                                auto drvOutput = get(drvOutputs, output);
-                                assert(drvOutput);
-                                assert(drvOutput->second);
-                                outputs.insert_or_assign(
-                                    output, *drvOutput->second);
-                            }
-                        }
-                        res.push_back({installable, BuiltPath::Built { bfd.drvPath, outputs }});
-                    },
-                    [&](const DerivedPath::Opaque & bo) {
-                        res.push_back({installable, BuiltPath::Opaque { bo.path }});
-                    },
-                }, path.raw());
-            }
-        }
-
-        break;
-
-    case Realise::Outputs: {
-        if (settings.printMissing)
-          printMissing(store, pathsToBuild, lvlInfo);
-
-        for (auto & buildResult : store->buildPathsWithResults(pathsToBuild, bMode, evalStore)) {
-            if (!buildResult.success())
-                buildResult.rethrow();
-
-            for (auto & installable : backmap[buildResult.path]) {
-                std::visit(overloaded {
-                    [&](const DerivedPath::Built & bfd) {
-                        std::map<std::string, StorePath> outputs;
-                        for (auto & path : buildResult.builtOutputs)
-                            outputs.emplace(path.first.outputName, path.second.outPath);
-                        res.push_back({installable, BuiltPath::Built { bfd.drvPath, outputs }});
-                    },
-                    [&](const DerivedPath::Opaque & bo) {
-                        res.push_back({installable, BuiltPath::Opaque { bo.path }});
-                    },
-                }, buildResult.path.raw());
-            }
-        }
-
-        break;
-    }
-
-    default:
-        assert(false);
-    }
-
-    return res;
+    return getBuiltPaths(evalStore, store, pathsToBuild);
 }
 
 BuiltPaths Installable::toBuiltPaths(
@@ -1042,30 +908,24 @@ InstallablesCommand::InstallablesCommand()
 
 void InstallablesCommand::prepare()
 {
-    installables = load();
-}
-
-Installables InstallablesCommand::load() {
-    Installables installables;
     if (_installables.empty() && useDefaultInstallables())
-        // FIXME: commands like "nix profile install" should not have a
+        // FIXME: commands like "nix install" should not have a
         // default, probably.
         _installables.push_back(".");
-    return parseInstallables(getStore(), _installables);
+    installables = parseInstallables(getStore(), _installables);
 }
 
-std::vector<std::string> InstallablesCommand::getFlakesForCompletion()
+std::optional<FlakeRef> InstallablesCommand::getFlakeRefForCompletion()
 {
     if (_installables.empty()) {
         if (useDefaultInstallables())
-            return {"."};
+            return parseFlakeRef(".", absPath("."));
         return {};
     }
-    return _installables;
+    return parseFlakeRef(_installables.front(), absPath("."));
 }
 
-InstallableCommand::InstallableCommand(bool supportReadOnlyMode)
-    : SourceExprCommand(supportReadOnlyMode)
+InstallableCommand::InstallableCommand()
 {
     expectArgs({
         .label = "installable",

src/libcmd/installables.hh

@@ -68,7 +68,7 @@ struct Installable
 
     UnresolvedApp toApp(EvalState & state);
 
-    virtual std::pair<Value *, PosIdx> toValue(EvalState & state)
+    virtual std::pair<Value *, Pos> toValue(EvalState & state)
     {
         throw Error("argument '%s' cannot be evaluated", what());
     }
@@ -80,10 +80,10 @@ struct Installable
         return {};
     }
 
-    virtual std::vector<ref<eval_cache::AttrCursor>>
+    virtual std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>>
     getCursors(EvalState & state);
 
-    virtual ref<eval_cache::AttrCursor>
+    std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>
     getCursor(EvalState & state);
 
     virtual FlakeRef nixpkgsFlakeRef() const
@@ -98,13 +98,6 @@ struct Installable
         const std::vector<std::shared_ptr<Installable>> & installables,
         BuildMode bMode = bmNormal);
 
-    static std::vector<std::pair<std::shared_ptr<Installable>, BuiltPath>> build2(
-        ref<Store> evalStore,
-        ref<Store> store,
-        Realise mode,
-        const std::vector<std::shared_ptr<Installable>> & installables,
-        BuildMode bMode = bmNormal);
-
     static std::set<StorePath> toStorePaths(
         ref<Store> evalStore,
         ref<Store> store,
@@ -132,8 +125,6 @@ struct Installable
         const std::vector<std::shared_ptr<Installable>> & installables);
 };
 
-typedef std::vector<std::shared_ptr<Installable>> Installables;
-
 struct InstallableValue : Installable
 {
     ref<EvalState> state;
@@ -143,8 +134,7 @@ struct InstallableValue : Installable
     struct DerivationInfo
     {
         StorePath drvPath;
-        std::set<std::string> outputsToInstall;
-        std::optional<NixInt> priority;
+        std::string outputName;
     };
 
     virtual std::vector<DerivationInfo> toDerivations() = 0;
@@ -159,7 +149,6 @@ struct InstallableFlake : InstallableValue
     FlakeRef flakeRef;
     Strings attrPaths;
     Strings prefixes;
-    OutputsSpec outputsSpec;
     const flake::LockFlags & lockFlags;
     mutable std::shared_ptr<flake::LockedFlake> _lockedFlake;
 
@@ -168,7 +157,6 @@ struct InstallableFlake : InstallableValue
         ref<EvalState> state,
         FlakeRef && flakeRef,
         std::string_view fragment,
-        OutputsSpec outputsSpec,
         Strings attrPaths,
         Strings prefixes,
         const flake::LockFlags & lockFlags);
@@ -183,17 +171,11 @@ struct InstallableFlake : InstallableValue
 
     std::vector<DerivationInfo> toDerivations() override;
 
-    std::pair<Value *, PosIdx> toValue(EvalState & state) override;
+    std::pair<Value *, Pos> toValue(EvalState & state) override;
 
-    /* Get a cursor to every attrpath in getActualAttrPaths() that
-       exists. */
-    std::vector<ref<eval_cache::AttrCursor>>
+    std::vector<std::pair<std::shared_ptr<eval_cache::AttrCursor>, std::string>>
     getCursors(EvalState & state) override;
 
-    /* Get a cursor to the first attrpath in getActualAttrPaths() that
-       exists, or throw an exception with suggestions if none exists. */
-    ref<eval_cache::AttrCursor> getCursor(EvalState & state) override;
-
     std::shared_ptr<flake::LockedFlake> getLockedFlake() const;
 
     FlakeRef nixpkgsFlakeRef() const override;
@@ -203,4 +185,9 @@ ref<eval_cache::EvalCache> openEvalCache(
     EvalState & state,
     std::shared_ptr<flake::LockedFlake> lockedFlake);
 
+BuiltPaths getBuiltPaths(
+    ref<Store> evalStore,
+    ref<Store> store,
+    const DerivedPaths & hopefullyBuiltPaths);
+
 }

src/libcmd/local.mk

@@ -6,9 +6,9 @@ libcmd_DIR := $(d)
 
 libcmd_SOURCES := $(wildcard $(d)/*.cc)
 
-libcmd_CXXFLAGS += -I src/libutil -I src/libstore -I src/libexpr -I src/libmain -I src/libfetchers -I src/nix
+libcmd_CXXFLAGS += -I src/libutil -I src/libstore -I src/libexpr -I src/libmain -I src/libfetchers
 
-libcmd_LDFLAGS = $(EDITLINE_LIBS) -llowdown -pthread
+libcmd_LDFLAGS += $(LOWDOWN_LIBS) -pthread
 
 libcmd_LIBS = libstore libutil libexpr libmain libfetchers
 

src/libcmd/markdown.cc

@@ -9,16 +9,14 @@ namespace nix {
 
 std::string renderMarkdownToTerminal(std::string_view markdown)
 {
-    int windowWidth = getWindowSize().second;
-
     struct lowdown_opts opts {
         .type = LOWDOWN_TERM,
         .maxdepth = 20,
-        .cols = (size_t) std::max(windowWidth - 5, 60),
+        .cols = std::max(getWindowSize().second, (unsigned short) 80),
         .hmargin = 0,
         .vmargin = 0,
         .feat = LOWDOWN_COMMONMARK | LOWDOWN_FENCED | LOWDOWN_DEFLIST | LOWDOWN_TABLES,
-        .oflags = LOWDOWN_TERM_NOLINK,
+        .oflags = 0,
     };
 
     auto doc = lowdown_doc_new(&opts);

src/libexpr/attr-path.cc

@@ -41,13 +41,13 @@ std::vector<Symbol> parseAttrPath(EvalState & state, std::string_view s)
 }
 
 
-std::pair<Value *, PosIdx> findAlongAttrPath(EvalState & state, const std::string & attrPath,
+std::pair<Value *, Pos> findAlongAttrPath(EvalState & state, const std::string & attrPath,
     Bindings & autoArgs, Value & vIn)
 {
     Strings tokens = parseAttrPath(attrPath);
 
     Value * v = &vIn;
-    PosIdx pos = noPos;
+    Pos pos = noPos;
 
     for (auto & attr : tokens) {
 
@@ -77,13 +77,13 @@ std::pair<Value *, PosIdx> findAlongAttrPath(EvalState & state, const std::strin
             if (a == v->attrs->end()) {
                 std::set<std::string> attrNames;
                 for (auto & attr : *v->attrs)
-                    attrNames.insert(state.symbols[attr.name]);
+                    attrNames.insert(attr.name);
 
                 auto suggestions = Suggestions::bestMatches(attrNames, attr);
                 throw AttrPathNotFound(suggestions, "attribute '%1%' in selection path '%2%' not found", attr, attrPath);
             }
             v = &*a->value;
-            pos = a->pos;
+            pos = *a->pos;
         }
 
         else {
@@ -106,7 +106,7 @@ std::pair<Value *, PosIdx> findAlongAttrPath(EvalState & state, const std::strin
 }
 
 
-std::pair<std::string, uint32_t> findPackageFilename(EvalState & state, Value & v, std::string what)
+Pos findPackageFilename(EvalState & state, Value & v, std::string what)
 {
     Value * v2;
     try {
@@ -132,7 +132,9 @@ std::pair<std::string, uint32_t> findPackageFilename(EvalState & state, Value &
         throw ParseError("cannot parse line number '%s'", pos);
     }
 
-    return { std::move(filename), lineno };
+    Symbol file = state.symbols.create(filename);
+
+    return { foFile, file, lineno, 0 };
 }
 
 

src/libexpr/attr-path.hh

@@ -10,14 +10,14 @@ namespace nix {
 MakeError(AttrPathNotFound, Error);
 MakeError(NoPositionInfo, Error);
 
-std::pair<Value *, PosIdx> findAlongAttrPath(
+std::pair<Value *, Pos> findAlongAttrPath(
     EvalState & state,
     const std::string & attrPath,
     Bindings & autoArgs,
     Value & vIn);
 
 /* Heuristic to find the filename and lineno or a nix value. */
-std::pair<std::string, uint32_t> findPackageFilename(EvalState & state, Value & v, std::string what);
+Pos findPackageFilename(EvalState & state, Value & v, std::string what);
 
 std::vector<Symbol> parseAttrPath(EvalState & state, std::string_view s);
 

src/libexpr/attr-set.cc

@@ -26,7 +26,7 @@ Bindings * EvalState::allocBindings(size_t capacity)
 /* Create a new attribute named 'name' on an existing attribute set stored
    in 'vAttrs' and return the newly allocated Value which is associated with
    this attribute. */
-Value * EvalState::allocAttr(Value & vAttrs, Symbol name)
+Value * EvalState::allocAttr(Value & vAttrs, const Symbol & name)
 {
     Value * v = allocValue();
     vAttrs.attrs->push_back(Attr(name, v));
@@ -40,7 +40,7 @@ Value * EvalState::allocAttr(Value & vAttrs, std::string_view name)
 }
 
 
-Value & BindingsBuilder::alloc(Symbol name, PosIdx pos)
+Value & BindingsBuilder::alloc(const Symbol & name, ptr<Pos> pos)
 {
     auto value = state.allocValue();
     bindings->push_back(Attr(name, value, pos));
@@ -48,7 +48,7 @@ Value & BindingsBuilder::alloc(Symbol name, PosIdx pos)
 }
 
 
-Value & BindingsBuilder::alloc(std::string_view name, PosIdx pos)
+Value & BindingsBuilder::alloc(std::string_view name, ptr<Pos> pos)
 {
     return alloc(state.symbols.create(name), pos);
 }

src/libexpr/attr-set.hh

@@ -15,27 +15,18 @@ struct Value;
 /* Map one attribute name to its value. */
 struct Attr
 {
-    /* the placement of `name` and `pos` in this struct is important.
-       both of them are uint32 wrappers, they are next to each other
-       to make sure that Attr has no padding on 64 bit machines. that
-       way we keep Attr size at two words with no wasted space. */
     Symbol name;
-    PosIdx pos;
     Value * value;
-    Attr(Symbol name, Value * value, PosIdx pos = noPos)
-        : name(name), pos(pos), value(value) { };
-    Attr() { };
+    ptr<Pos> pos;
+    Attr(Symbol name, Value * value, ptr<Pos> pos = ptr(&noPos))
+        : name(name), value(value), pos(pos) { };
+    Attr() : pos(&noPos) { };
     bool operator < (const Attr & a) const
     {
         return name < a.name;
     }
 };
 
-static_assert(sizeof(Attr) == 2 * sizeof(uint32_t) + sizeof(Value *),
-    "performance of the evaluator is highly sensitive to the size of Attr. "
-    "avoid introducing any padding into Attr if at all possible, and do not "
-    "introduce new fields that need not be present for almost every instance.");
-
 /* Bindings contains all the attributes of an attribute set. It is defined
    by its size and its capacity, the capacity being the number of Attr
    elements allocated after this structure, while the size corresponds to
@@ -44,13 +35,13 @@ class Bindings
 {
 public:
     typedef uint32_t size_t;
-    PosIdx pos;
+    ptr<Pos> pos;
 
 private:
     size_t size_, capacity_;
     Attr attrs[0];
 
-    Bindings(size_t capacity) : size_(0), capacity_(capacity) { }
+    Bindings(size_t capacity) : pos(&noPos), size_(0), capacity_(capacity) { }
     Bindings(const Bindings & bindings) = delete;
 
 public:
@@ -66,7 +57,7 @@ public:
         attrs[size_++] = attr;
     }
 
-    iterator find(Symbol name)
+    iterator find(const Symbol & name)
     {
         Attr key(name, 0);
         iterator i = std::lower_bound(begin(), end(), key);
@@ -74,7 +65,7 @@ public:
         return end();
     }
 
-    Attr * get(Symbol name)
+    Attr * get(const Symbol & name)
     {
         Attr key(name, 0);
         iterator i = std::lower_bound(begin(), end(), key);
@@ -82,6 +73,18 @@ public:
         return nullptr;
     }
 
+    Attr & need(const Symbol & name, const Pos & pos = noPos)
+    {
+        auto a = get(name);
+        if (!a)
+            throw Error({
+                .msg = hintfmt("attribute '%s' missing", name),
+                .errPos = pos
+            });
+
+        return *a;
+    }
+
     iterator begin() { return &attrs[0]; }
     iterator end() { return &attrs[size_]; }
 
@@ -95,15 +98,14 @@ public:
     size_t capacity() { return capacity_; }
 
     /* Returns the attributes in lexicographically sorted order. */
-    std::vector<const Attr *> lexicographicOrder(const SymbolTable & symbols) const
+    std::vector<const Attr *> lexicographicOrder() const
     {
         std::vector<const Attr *> res;
         res.reserve(size_);
         for (size_t n = 0; n < size_; n++)
             res.emplace_back(&attrs[n]);
-        std::sort(res.begin(), res.end(), [&](const Attr * a, const Attr * b) {
-            std::string_view sa = symbols[a->name], sb = symbols[b->name];
-            return sa < sb;
+        std::sort(res.begin(), res.end(), [](const Attr * a, const Attr * b) {
+            return (const std::string &) a->name < (const std::string &) b->name;
         });
         return res;
     }
@@ -128,7 +130,7 @@ public:
         : bindings(bindings), state(state)
     { }
 
-    void insert(Symbol name, Value * value, PosIdx pos = noPos)
+    void insert(Symbol name, Value * value, ptr<Pos> pos = ptr(&noPos))
     {
         insert(Attr(name, value, pos));
     }
@@ -143,9 +145,9 @@ public:
         bindings->push_back(attr);
     }
 
-    Value & alloc(Symbol name, PosIdx pos = noPos);
+    Value & alloc(const Symbol & name, ptr<Pos> pos = ptr(&noPos));
 
-    Value & alloc(std::string_view name, PosIdx pos = noPos);
+    Value & alloc(std::string_view name, ptr<Pos> pos = ptr(&noPos));
 
     Bindings * finish()
     {

src/libexpr/common-eval-args.cc

@@ -7,7 +7,6 @@
 #include "registry.hh"
 #include "flake/flakeref.hh"
 #include "store-api.hh"
-#include "command.hh"
 
 namespace nix {
 
@@ -60,9 +59,6 @@ MixEvalArgs::MixEvalArgs()
             fetchers::Attrs extraAttrs;
             if (to.subdir != "") extraAttrs["dir"] = to.subdir;
             fetchers::overrideRegistry(from.input, to.input, extraAttrs);
-        }},
-        .completer = {[&](size_t, std::string_view prefix) {
-            completeFlakeRef(openStore(), prefix);
         }}
     });
 

src/libexpr/eval-cache.cc

@@ -21,8 +21,6 @@ struct AttrDb
 {
     std::atomic_bool failed{false};
 
-    const Store & cfg;
-
     struct State
     {
         SQLite db;
@@ -35,19 +33,12 @@ struct AttrDb
 
     std::unique_ptr<Sync<State>> _state;
 
-    SymbolTable & symbols;
-
-    AttrDb(
-        const Store & cfg,
-        const Hash & fingerprint,
-        SymbolTable & symbols)
-        : cfg(cfg)
-        , _state(std::make_unique<Sync<State>>())
-        , symbols(symbols)
+    AttrDb(const Hash & fingerprint)
+        : _state(std::make_unique<Sync<State>>())
     {
         auto state(_state->lock());
 
-        Path cacheDir = getCacheDir() + "/nix/eval-cache-v4";
+        Path cacheDir = getCacheDir() + "/nix/eval-cache-v2";
         createDirs(cacheDir);
 
         Path dbPath = cacheDir + "/" + fingerprint.to_string(Base16, false) + ".sqlite";
@@ -106,7 +97,7 @@ struct AttrDb
 
             state->insertAttribute.use()
                 (key.first)
-                (symbols[key.second])
+                (key.second)
                 (AttrType::FullAttrs)
                 (0, false).exec();
 
@@ -116,7 +107,7 @@ struct AttrDb
             for (auto & attr : attrs)
                 state->insertAttribute.use()
                     (rowId)
-                    (symbols[attr])
+                    (attr)
                     (AttrType::Placeholder)
                     (0, false).exec();
 
@@ -141,14 +132,14 @@ struct AttrDb
                 }
                 state->insertAttributeWithContext.use()
                     (key.first)
-                    (symbols[key.second])
+                    (key.second)
                     (AttrType::String)
                     (s)
                     (ctx).exec();
             } else {
                 state->insertAttribute.use()
                     (key.first)
-                    (symbols[key.second])
+                    (key.second)
                     (AttrType::String)
                 (s).exec();
             }
@@ -167,7 +158,7 @@ struct AttrDb
 
             state->insertAttribute.use()
                 (key.first)
-                (symbols[key.second])
+                (key.second)
                 (AttrType::Bool)
                 (b ? 1 : 0).exec();
 
@@ -175,42 +166,6 @@ struct AttrDb
         });
     }
 
-    AttrId setInt(
-        AttrKey key,
-        int n)
-    {
-        return doSQLite([&]()
-        {
-            auto state(_state->lock());
-
-            state->insertAttribute.use()
-                (key.first)
-                (symbols[key.second])
-                (AttrType::Int)
-                (n).exec();
-
-            return state->db.getLastInsertedRowId();
-        });
-    }
-
-    AttrId setListOfStrings(
-        AttrKey key,
-        const std::vector<std::string> & l)
-    {
-        return doSQLite([&]()
-        {
-            auto state(_state->lock());
-
-            state->insertAttribute.use()
-                (key.first)
-                (symbols[key.second])
-                (AttrType::ListOfStrings)
-                (concatStringsSep("\t", l)).exec();
-
-            return state->db.getLastInsertedRowId();
-        });
-    }
-
     AttrId setPlaceholder(AttrKey key)
     {
         return doSQLite([&]()
@@ -219,7 +174,7 @@ struct AttrDb
 
             state->insertAttribute.use()
                 (key.first)
-                (symbols[key.second])
+                (key.second)
                 (AttrType::Placeholder)
                 (0, false).exec();
 
@@ -235,7 +190,7 @@ struct AttrDb
 
             state->insertAttribute.use()
                 (key.first)
-                (symbols[key.second])
+                (key.second)
                 (AttrType::Missing)
                 (0, false).exec();
 
@@ -251,7 +206,7 @@ struct AttrDb
 
             state->insertAttribute.use()
                 (key.first)
-                (symbols[key.second])
+                (key.second)
                 (AttrType::Misc)
                 (0, false).exec();
 
@@ -267,7 +222,7 @@ struct AttrDb
 
             state->insertAttribute.use()
                 (key.first)
-                (symbols[key.second])
+                (key.second)
                 (AttrType::Failed)
                 (0, false).exec();
 
@@ -275,14 +230,16 @@ struct AttrDb
         });
     }
 
-    std::optional<std::pair<AttrId, AttrValue>> getAttr(AttrKey key)
+    std::optional<std::pair<AttrId, AttrValue>> getAttr(
+        AttrKey key,
+        SymbolTable & symbols)
     {
         auto state(_state->lock());
 
-        auto queryAttribute(state->queryAttribute.use()(key.first)(symbols[key.second]));
+        auto queryAttribute(state->queryAttribute.use()(key.first)(key.second));
         if (!queryAttribute.next()) return {};
 
-        auto rowId = (AttrId) queryAttribute.getInt(0);
+        auto rowId = (AttrType) queryAttribute.getInt(0);
         auto type = (AttrType) queryAttribute.getInt(1);
 
         switch (type) {
@@ -293,22 +250,18 @@ struct AttrDb
                 std::vector<Symbol> attrs;
                 auto queryAttributes(state->queryAttributes.use()(rowId));
                 while (queryAttributes.next())
-                    attrs.emplace_back(symbols.create(queryAttributes.getStr(0)));
+                    attrs.push_back(symbols.create(queryAttributes.getStr(0)));
                 return {{rowId, attrs}};
             }
             case AttrType::String: {
-                NixStringContext context;
+                std::vector<std::pair<Path, std::string>> context;
                 if (!queryAttribute.isNull(3))
                     for (auto & s : tokenizeString<std::vector<std::string>>(queryAttribute.getStr(3), ";"))
-                        context.push_back(decodeContext(cfg, s));
+                        context.push_back(decodeContext(s));
                 return {{rowId, string_t{queryAttribute.getStr(2), context}}};
             }
             case AttrType::Bool:
                 return {{rowId, queryAttribute.getInt(2) != 0}};
-            case AttrType::Int:
-                return {{rowId, int_t{queryAttribute.getInt(2)}}};
-            case AttrType::ListOfStrings:
-                return {{rowId, tokenizeString<std::vector<std::string>>(queryAttribute.getStr(2), "\t")}};
             case AttrType::Missing:
                 return {{rowId, missing_t()}};
             case AttrType::Misc:
@@ -321,13 +274,10 @@ struct AttrDb
     }
 };
 
-static std::shared_ptr<AttrDb> makeAttrDb(
-    const Store & cfg,
-    const Hash & fingerprint,
-    SymbolTable & symbols)
+static std::shared_ptr<AttrDb> makeAttrDb(const Hash & fingerprint)
 {
     try {
-        return std::make_shared<AttrDb>(cfg, fingerprint, symbols);
+        return std::make_shared<AttrDb>(fingerprint);
     } catch (SQLiteError &) {
         ignoreException();
         return nullptr;
@@ -338,7 +288,7 @@ EvalCache::EvalCache(
     std::optional<std::reference_wrapper<const Hash>> useCache,
     EvalState & state,
     RootLoader rootLoader)
-    : db(useCache ? makeAttrDb(*state.store, *useCache, state.symbols) : nullptr)
+    : db(useCache ? makeAttrDb(*useCache) : nullptr)
     , state(state)
     , rootLoader(rootLoader)
 {
@@ -353,9 +303,9 @@ Value * EvalCache::getRootValue()
     return *value;
 }
 
-ref<AttrCursor> EvalCache::getRoot()
+std::shared_ptr<AttrCursor> EvalCache::getRoot()
 {
-    return make_ref<AttrCursor>(ref(shared_from_this()), std::nullopt);
+    return std::make_shared<AttrCursor>(ref(shared_from_this()), std::nullopt);
 }
 
 AttrCursor::AttrCursor(
@@ -374,7 +324,8 @@ AttrKey AttrCursor::getKey()
     if (!parent)
         return {0, root->state.sEpsilon};
     if (!parent->first->cachedValue) {
-        parent->first->cachedValue = root->db->getAttr(parent->first->getKey());
+        parent->first->cachedValue = root->db->getAttr(
+            parent->first->getKey(), root->state.symbols);
         assert(parent->first->cachedValue);
     }
     return {parent->first->cachedValue->first, parent->second};
@@ -415,17 +366,17 @@ std::vector<Symbol> AttrCursor::getAttrPath(Symbol name) const
 
 std::string AttrCursor::getAttrPathStr() const
 {
-    return concatStringsSep(".", root->state.symbols.resolve(getAttrPath()));
+    return concatStringsSep(".", getAttrPath());
 }
 
 std::string AttrCursor::getAttrPathStr(Symbol name) const
 {
-    return concatStringsSep(".", root->state.symbols.resolve(getAttrPath(name)));
+    return concatStringsSep(".", getAttrPath(name));
 }
 
 Value & AttrCursor::forceValue()
 {
-    debug("evaluating uncached attribute '%s'", getAttrPathStr());
+    debug("evaluating uncached attribute %s", getAttrPathStr());
 
     auto & v = getValue();
 
@@ -446,8 +397,6 @@ Value & AttrCursor::forceValue()
             cachedValue = {root->db->setString(getKey(), v.path), string_t{v.path, {}}};
         else if (v.type() == nBool)
             cachedValue = {root->db->setBool(getKey(), v.boolean), v.boolean};
-        else if (v.type() == nInt)
-            cachedValue = {root->db->setInt(getKey(), v.integer), int_t{v.integer}};
         else if (v.type() == nAttrs)
             ; // FIXME: do something?
         else
@@ -462,31 +411,31 @@ Suggestions AttrCursor::getSuggestionsForAttr(Symbol name)
     auto attrNames = getAttrs();
     std::set<std::string> strAttrNames;
     for (auto & name : attrNames)
-        strAttrNames.insert(root->state.symbols[name]);
+        strAttrNames.insert(std::string(name));
 
-    return Suggestions::bestMatches(strAttrNames, root->state.symbols[name]);
+    return Suggestions::bestMatches(strAttrNames, name);
 }
 
 std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErrors)
 {
     if (root->db) {
         if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
+            cachedValue = root->db->getAttr(getKey(), root->state.symbols);
 
         if (cachedValue) {
             if (auto attrs = std::get_if<std::vector<Symbol>>(&cachedValue->second)) {
                 for (auto & attr : *attrs)
                     if (attr == name)
-                        return std::make_shared<AttrCursor>(root, std::make_pair(shared_from_this(), attr));
+                        return std::make_shared<AttrCursor>(root, std::make_pair(shared_from_this(), name));
                 return nullptr;
             } else if (std::get_if<placeholder_t>(&cachedValue->second)) {
-                auto attr = root->db->getAttr({cachedValue->first, name});
+                auto attr = root->db->getAttr({cachedValue->first, name}, root->state.symbols);
                 if (attr) {
                     if (std::get_if<missing_t>(&attr->second))
                         return nullptr;
                     else if (std::get_if<failed_t>(&attr->second)) {
                         if (forceErrors)
-                            debug("reevaluating failed cached attribute '%s'", getAttrPathStr(name));
+                            debug("reevaluating failed cached attribute '%s'");
                         else
                             throw CachedEvalError("cached failure of attribute '%s'", getAttrPathStr(name));
                     } else
@@ -507,6 +456,11 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErro
         return nullptr;
         //throw TypeError("'%s' is not an attribute set", getAttrPathStr());
 
+    for (auto & attr : *v.attrs) {
+        if (root->db)
+            root->db->setPlaceholder({cachedValue->first, attr.name});
+    }
+
     auto attr = v.attrs->get(name);
 
     if (!attr) {
@@ -565,20 +519,20 @@ std::string AttrCursor::getString()
 {
     if (root->db) {
         if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
+            cachedValue = root->db->getAttr(getKey(), root->state.symbols);
         if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
             if (auto s = std::get_if<string_t>(&cachedValue->second)) {
                 debug("using cached string attribute '%s'", getAttrPathStr());
                 return s->first;
             } else
-                root->state.debugThrowLastTrace(TypeError("'%s' is not a string", getAttrPathStr()));
+                throw TypeError("'%s' is not a string", getAttrPathStr());
         }
     }
 
     auto & v = forceValue();
 
     if (v.type() != nString && v.type() != nPath)
-        root->state.debugThrowLastTrace(TypeError("'%s' is not a string but %s", getAttrPathStr(), showType(v.type())));
+        throw TypeError("'%s' is not a string but %s", getAttrPathStr(), showType(v.type()));
 
     return v.type() == nString ? v.string.s : v.path;
 }
@@ -587,12 +541,12 @@ string_t AttrCursor::getStringWithContext()
 {
     if (root->db) {
         if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
+            cachedValue = root->db->getAttr(getKey(), root->state.symbols);
         if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
             if (auto s = std::get_if<string_t>(&cachedValue->second)) {
                 bool valid = true;
                 for (auto & c : s->second) {
-                    if (!root->state.store->isValidPath(c.first)) {
+                    if (!root->state.store->isValidPath(root->state.store->parseStorePath(c.first))) {
                         valid = false;
                         break;
                     }
@@ -602,122 +556,66 @@ string_t AttrCursor::getStringWithContext()
                     return *s;
                 }
             } else
-                root->state.debugThrowLastTrace(TypeError("'%s' is not a string", getAttrPathStr()));
+                throw TypeError("'%s' is not a string", getAttrPathStr());
         }
     }
 
     auto & v = forceValue();
 
     if (v.type() == nString)
-        return {v.string.s, v.getContext(*root->state.store)};
+        return {v.string.s, v.getContext()};
     else if (v.type() == nPath)
         return {v.path, {}};
     else
-        root->state.debugThrowLastTrace(TypeError("'%s' is not a string but %s", getAttrPathStr(), showType(v.type())));
+        throw TypeError("'%s' is not a string but %s", getAttrPathStr(), showType(v.type()));
 }
 
 bool AttrCursor::getBool()
 {
     if (root->db) {
         if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
+            cachedValue = root->db->getAttr(getKey(), root->state.symbols);
         if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
             if (auto b = std::get_if<bool>(&cachedValue->second)) {
                 debug("using cached Boolean attribute '%s'", getAttrPathStr());
                 return *b;
             } else
-                root->state.debugThrowLastTrace(TypeError("'%s' is not a Boolean", getAttrPathStr()));
+                throw TypeError("'%s' is not a Boolean", getAttrPathStr());
         }
     }
 
     auto & v = forceValue();
 
     if (v.type() != nBool)
-        root->state.debugThrowLastTrace(TypeError("'%s' is not a Boolean", getAttrPathStr()));
+        throw TypeError("'%s' is not a Boolean", getAttrPathStr());
 
     return v.boolean;
 }
 
-NixInt AttrCursor::getInt()
-{
-    if (root->db) {
-        if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
-        if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
-            if (auto i = std::get_if<int_t>(&cachedValue->second)) {
-                debug("using cached Integer attribute '%s'", getAttrPathStr());
-                return i->x;
-            } else
-                throw TypeError("'%s' is not an Integer", getAttrPathStr());
-        }
-    }
-
-    auto & v = forceValue();
-
-    if (v.type() != nInt)
-        throw TypeError("'%s' is not an Integer", getAttrPathStr());
-
-    return v.integer;
-}
-
-std::vector<std::string> AttrCursor::getListOfStrings()
-{
-    if (root->db) {
-        if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
-        if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
-            if (auto l = std::get_if<std::vector<std::string>>(&cachedValue->second)) {
-                debug("using cached list of strings attribute '%s'", getAttrPathStr());
-                return *l;
-            } else
-                throw TypeError("'%s' is not a list of strings", getAttrPathStr());
-        }
-    }
-
-    debug("evaluating uncached attribute '%s'", getAttrPathStr());
-
-    auto & v = getValue();
-    root->state.forceValue(v, noPos);
-
-    if (v.type() != nList)
-        throw TypeError("'%s' is not a list", getAttrPathStr());
-
-    std::vector<std::string> res;
-
-    for (auto & elem : v.listItems())
-        res.push_back(std::string(root->state.forceStringNoCtx(*elem)));
-
-    if (root->db)
-        cachedValue = {root->db->setListOfStrings(getKey(), res), res};
-
-    return res;
-}
-
 std::vector<Symbol> AttrCursor::getAttrs()
 {
     if (root->db) {
         if (!cachedValue)
-            cachedValue = root->db->getAttr(getKey());
+            cachedValue = root->db->getAttr(getKey(), root->state.symbols);
         if (cachedValue && !std::get_if<placeholder_t>(&cachedValue->second)) {
             if (auto attrs = std::get_if<std::vector<Symbol>>(&cachedValue->second)) {
                 debug("using cached attrset attribute '%s'", getAttrPathStr());
                 return *attrs;
             } else
-                root->state.debugThrowLastTrace(TypeError("'%s' is not an attribute set", getAttrPathStr()));
+                throw TypeError("'%s' is not an attribute set", getAttrPathStr());
         }
     }
 
     auto & v = forceValue();
 
     if (v.type() != nAttrs)
-        root->state.debugThrowLastTrace(TypeError("'%s' is not an attribute set", getAttrPathStr()));
+        throw TypeError("'%s' is not an attribute set", getAttrPathStr());
 
     std::vector<Symbol> attrs;
     for (auto & attr : *getValue().attrs)
         attrs.push_back(attr.name);
-    std::sort(attrs.begin(), attrs.end(), [&](Symbol a, Symbol b) {
-        std::string_view sa = root->state.symbols[a], sb = root->state.symbols[b];
-        return sa < sb;
+    std::sort(attrs.begin(), attrs.end(), [](const Symbol & a, const Symbol & b) {
+        return (const std::string &) a < (const std::string &) b;
     });
 
     if (root->db)

src/libexpr/eval-cache.hh

@@ -33,7 +33,7 @@ public:
         EvalState & state,
         RootLoader rootLoader);
 
-    ref<AttrCursor> getRoot();
+    std::shared_ptr<AttrCursor> getRoot();
 };
 
 enum AttrType {
@@ -44,18 +44,15 @@ enum AttrType {
     Misc = 4,
     Failed = 5,
     Bool = 6,
-    ListOfStrings = 7,
-    Int = 8,
 };
 
 struct placeholder_t {};
 struct missing_t {};
 struct misc_t {};
 struct failed_t {};
-struct int_t { NixInt x; };
 typedef uint64_t AttrId;
 typedef std::pair<AttrId, Symbol> AttrKey;
-typedef std::pair<std::string, NixStringContext> string_t;
+typedef std::pair<std::string, std::vector<std::pair<Path, std::string>>> string_t;
 
 typedef std::variant<
     std::vector<Symbol>,
@@ -64,9 +61,7 @@ typedef std::variant<
     missing_t,
     misc_t,
     failed_t,
-    bool,
-    int_t,
-    std::vector<std::string>
+    bool
     > AttrValue;
 
 class AttrCursor : public std::enable_shared_from_this<AttrCursor>
@@ -109,8 +104,6 @@ public:
 
     ref<AttrCursor> getAttr(std::string_view name);
 
-    /* Get an attribute along a chain of attrsets. Note that this does
-       not auto-call functors or functions. */
     OrSuggestions<ref<AttrCursor>> findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force = false);
 
     std::string getString();
@@ -119,10 +112,6 @@ public:
 
     bool getBool();
 
-    NixInt getInt();
-
-    std::vector<std::string> getListOfStrings();
-
     std::vector<Symbol> getAttrs();
 
     bool isDerivation();

src/libexpr/eval-inline.hh

@@ -2,84 +2,29 @@
 
 #include "eval.hh"
 
+#define LocalNoInline(f) static f __attribute__((noinline)); f
+#define LocalNoInlineNoReturn(f) static f __attribute__((noinline, noreturn)); f
+
 namespace nix {
 
-/* Note: Various places expect the allocated memory to be zeroed. */
-[[gnu::always_inline]]
-inline void * allocBytes(size_t n)
+LocalNoInlineNoReturn(void throwEvalError(const Pos & pos, const char * s))
 {
-    void * p;
-#if HAVE_BOEHMGC
-    p = GC_MALLOC(n);
-#else
-    p = calloc(n, 1);
-#endif
-    if (!p) throw std::bad_alloc();
-    return p;
+    throw EvalError({
+        .msg = hintfmt(s),
+        .errPos = pos
+    });
+}
+
+LocalNoInlineNoReturn(void throwTypeError(const Pos & pos, const char * s, const Value & v))
+{
+    throw TypeError({
+        .msg = hintfmt(s, showType(v)),
+        .errPos = pos
+    });
 }
 
 
-[[gnu::always_inline]]
-Value * EvalState::allocValue()
-{
-#if HAVE_BOEHMGC
-    /* We use the boehm batch allocator to speed up allocations of Values (of which there are many).
-       GC_malloc_many returns a linked list of objects of the given size, where the first word
-       of each object is also the pointer to the next object in the list. This also means that we
-       have to explicitly clear the first word of every object we take. */
-    if (!*valueAllocCache) {
-        *valueAllocCache = GC_malloc_many(sizeof(Value));
-        if (!*valueAllocCache) throw std::bad_alloc();
-    }
-
-    /* GC_NEXT is a convenience macro for accessing the first word of an object.
-       Take the first list item, advance the list to the next item, and clear the next pointer. */
-    void * p = *valueAllocCache;
-    *valueAllocCache = GC_NEXT(p);
-    GC_NEXT(p) = nullptr;
-#else
-    void * p = allocBytes(sizeof(Value));
-#endif
-
-    nrValues++;
-    return (Value *) p;
-}
-
-
-[[gnu::always_inline]]
-Env & EvalState::allocEnv(size_t size)
-{
-    nrEnvs++;
-    nrValuesInEnvs += size;
-
-    Env * env;
-
-#if HAVE_BOEHMGC
-    if (size == 1) {
-        /* see allocValue for explanations. */
-        if (!*env1AllocCache) {
-            *env1AllocCache = GC_malloc_many(sizeof(Env) + sizeof(Value *));
-            if (!*env1AllocCache) throw std::bad_alloc();
-        }
-
-        void * p = *env1AllocCache;
-        *env1AllocCache = GC_NEXT(p);
-        GC_NEXT(p) = nullptr;
-        env = (Env *) p;
-    } else
-#endif
-        env = (Env *) allocBytes(sizeof(Env) + size * sizeof(Value *));
-
-    env->type = Env::Plain;
-
-    /* We assume that env->values has been cleared by the allocator; maybeThunk() and lookupVar fromWith expect this. */
-
-    return *env;
-}
-
-
-[[gnu::always_inline]]
-void EvalState::forceValue(Value & v, const PosIdx pos)
+void EvalState::forceValue(Value & v, const Pos & pos)
 {
     forceValue(v, [&]() { return pos; });
 }
@@ -107,15 +52,13 @@ void EvalState::forceValue(Value & v, Callable getPos)
 }
 
 
-[[gnu::always_inline]]
-inline void EvalState::forceAttrs(Value & v, const PosIdx pos)
+inline void EvalState::forceAttrs(Value & v, const Pos & pos)
 {
     forceAttrs(v, [&]() { return pos; });
 }
 
 
 template <typename Callable>
-[[gnu::always_inline]]
 inline void EvalState::forceAttrs(Value & v, Callable getPos)
 {
     forceValue(v, getPos);
@@ -124,13 +67,25 @@ inline void EvalState::forceAttrs(Value & v, Callable getPos)
 }
 
 
-[[gnu::always_inline]]
-inline void EvalState::forceList(Value & v, const PosIdx pos)
+inline void EvalState::forceList(Value & v, const Pos & pos)
 {
     forceValue(v, pos);
     if (!v.isList())
         throwTypeError(pos, "value is %1% while a list was expected", v);
 }
 
+/* Note: Various places expect the allocated memory to be zeroed. */
+inline void * allocBytes(size_t n)
+{
+    void * p;
+#if HAVE_BOEHMGC
+    p = GC_MALLOC(n);
+#else
+    p = calloc(n, 1);
+#endif
+    if (!p) throw std::bad_alloc();
+    return p;
+}
+
 
 }

src/libexpr/eval.hh

@@ -13,6 +13,7 @@
 #include <unordered_map>
 #include <mutex>
 
+
 namespace nix {
 
 
@@ -22,22 +23,18 @@ class StorePath;
 enum RepairFlag : bool;
 
 
-typedef void (* PrimOpFun) (EvalState & state, const PosIdx pos, Value * * args, Value & v);
+typedef void (* PrimOpFun) (EvalState & state, const Pos & pos, Value * * args, Value & v);
+
 
 struct PrimOp
 {
     PrimOpFun fun;
     size_t arity;
-    std::string name;
+    Symbol name;
     std::vector<std::string> args;
     const char * doc = nullptr;
 };
 
-#if HAVE_BOEHMGC
-    typedef std::map<std::string, Value *, std::less<std::string>, traceable_allocator<std::pair<const std::string, Value *> > > ValMap;
-#else
-    typedef std::map<std::string, Value *> ValMap;
-#endif
 
 struct Env
 {
@@ -47,10 +44,6 @@ struct Env
     Value * values[0];
 };
 
-void printEnvBindings(const EvalState &es, const Expr & expr, const Env & env);
-void printEnvBindings(const SymbolTable & st, const StaticEnv & se, const Env & env, int lvl = 0);
-
-std::unique_ptr<ValMap> mapStaticEnvBindings(const SymbolTable & st, const StaticEnv & se, const Env & env);
 
 void copyContext(const Value & v, PathSet & context);
 
@@ -60,9 +53,7 @@ void copyContext(const Value & v, PathSet & context);
 typedef std::map<Path, StorePath> SrcToStore;
 
 
-std::ostream & printValue(const EvalState & state, std::ostream & str, const Value & v);
-std::string printValue(const EvalState & state, const Value & v);
-std::ostream & operator << (std::ostream & os, const ValueType t);
+std::ostream & operator << (std::ostream & str, const Value & v);
 
 
 typedef std::pair<std::string, std::string> SearchPathElem;
@@ -77,34 +68,21 @@ struct RegexCache;
 
 std::shared_ptr<RegexCache> makeRegexCache();
 
-struct DebugTrace {
-    std::optional<ErrPos> pos;
-    const Expr & expr;
-    const Env & env;
-    hintformat hint;
-    bool isError;
-};
 
-void debugError(Error * e, Env & env, Expr & expr);
-
-class EvalState : public std::enable_shared_from_this<EvalState>
+class EvalState
 {
 public:
     SymbolTable symbols;
-    PosTable positions;
-
-    static inline std::string derivationNixPath = "//builtin/derivation.nix";
 
     const Symbol sWith, sOutPath, sDrvPath, sType, sMeta, sName, sValue,
         sSystem, sOverrides, sOutputs, sOutputName, sIgnoreNulls,
         sFile, sLine, sColumn, sFunctor, sToString,
         sRight, sWrong, sStructuredAttrs, sBuilder, sArgs,
-        sContentAddressed, sImpure,
+        sContentAddressed,
         sOutputHash, sOutputHashAlgo, sOutputHashMode,
         sRecurseForDerivations,
         sDescription, sSelf, sEpsilon, sStartSet, sOperator, sKey, sPath,
-        sPrefix,
-        sOutputSpecified;
+        sPrefix;
     Symbol sDerivationNix;
 
     /* If set, force copying files to the Nix store even if they
@@ -126,56 +104,12 @@ public:
     RootValue vCallFlake = nullptr;
     RootValue vImportedDrvToDerivation = nullptr;
 
-    /* Debugger */
-    void (* debugRepl)(ref<EvalState> es, const ValMap & extraEnv);
-    bool debugStop;
-    bool debugQuit;
-    int trylevel;
-    std::list<DebugTrace> debugTraces;
-    std::map<const Expr*, const std::shared_ptr<const StaticEnv>> exprEnvs;
-    const std::shared_ptr<const StaticEnv> getStaticEnv(const Expr & expr) const
-    {
-        auto i = exprEnvs.find(&expr);
-        if (i != exprEnvs.end())
-            return i->second;
-        else
-            return std::shared_ptr<const StaticEnv>();;
-    }
-
-    void runDebugRepl(const Error * error, const Env & env, const Expr & expr);
-
-    template<class E>
-    [[gnu::noinline, gnu::noreturn]]
-    void debugThrow(E && error, const Env & env, const Expr & expr)
-    {
-        if (debugRepl)
-            runDebugRepl(&error, env, expr);
-
-        throw std::move(error);
-    }
-
-    template<class E>
-    [[gnu::noinline, gnu::noreturn]]
-    void debugThrowLastTrace(E && e)
-    {
-        // Call this in the situation where Expr and Env are inaccessible.
-        // The debugger will start in the last context that's in the
-        // DebugTrace stack.
-        if (debugRepl && !debugTraces.empty()) {
-            const DebugTrace & last = debugTraces.front();
-            runDebugRepl(&e, last.env, last.expr);
-        }
-
-        throw std::move(e);
-    }
-
-
 private:
     SrcToStore srcToStore;
 
     /* A cache from path names to parse trees. */
 #if HAVE_BOEHMGC
-    typedef std::map<Path, Expr *, std::less<Path>, traceable_allocator<std::pair<const Path, Expr *>>> FileParseCache;
+    typedef std::map<Path, Expr *, std::less<Path>, traceable_allocator<std::pair<const Path, Expr *> > > FileParseCache;
 #else
     typedef std::map<Path, Expr *> FileParseCache;
 #endif
@@ -183,7 +117,7 @@ private:
 
     /* A cache from path names to values. */
 #if HAVE_BOEHMGC
-    typedef std::map<Path, Value, std::less<Path>, traceable_allocator<std::pair<const Path, Value>>> FileEvalCache;
+    typedef std::map<Path, Value, std::less<Path>, traceable_allocator<std::pair<const Path, Value> > > FileEvalCache;
 #else
     typedef std::map<Path, Value> FileEvalCache;
 #endif
@@ -199,14 +133,9 @@ private:
     /* Cache used by prim_match(). */
     std::shared_ptr<RegexCache> regexCache;
 
-#if HAVE_BOEHMGC
     /* Allocation cache for GC'd Value objects. */
     std::shared_ptr<void *> valueAllocCache;
 
-    /* Allocation cache for size-1 Env objects. */
-    std::shared_ptr<void *> env1AllocCache;
-#endif
-
 public:
 
     EvalState(
@@ -215,6 +144,12 @@ public:
         std::shared_ptr<Store> buildStore = nullptr);
     ~EvalState();
 
+    void requireExperimentalFeatureOnEvaluation(
+        const ExperimentalFeature &,
+        const std::string_view fName,
+        const Pos & pos
+    );
+
     void addToSearchPath(const std::string & s);
 
     SearchPath getSearchPath() { return searchPath; }
@@ -246,10 +181,10 @@ public:
 
     /* Parse a Nix expression from the specified file. */
     Expr * parseExprFromFile(const Path & path);
-    Expr * parseExprFromFile(const Path & path, std::shared_ptr<StaticEnv> & staticEnv);
+    Expr * parseExprFromFile(const Path & path, StaticEnv & staticEnv);
 
     /* Parse a Nix expression from the specified string. */
-    Expr * parseExprFromString(std::string s, const Path & basePath, std::shared_ptr<StaticEnv> & staticEnv);
+    Expr * parseExprFromString(std::string s, const Path & basePath, StaticEnv & staticEnv);
     Expr * parseExprFromString(std::string s, const Path & basePath);
 
     Expr * parseStdin();
@@ -259,7 +194,7 @@ public:
        trivial (i.e. doesn't require arbitrary computation). */
     void evalFile(const Path & path, Value & v, bool mustBeTrivial = false);
 
-    /* Like `evalFile`, but with an already parsed expression. */
+    /* Like `cacheFile`, but with an already parsed expression. */
     void cacheFile(
         const Path & path,
         const Path & resolvedPath,
@@ -271,7 +206,7 @@ public:
 
     /* Look up a file in the search path. */
     Path findFile(const std::string_view path);
-    Path findFile(SearchPath & searchPath, const std::string_view path, const PosIdx pos = noPos);
+    Path findFile(SearchPath & searchPath, const std::string_view path, const Pos & pos = noPos);
 
     /* If the specified search path element is a URI, download it. */
     std::pair<bool, std::string> resolveSearchPathElem(const SearchPathElem & elem);
@@ -283,14 +218,14 @@ public:
     /* Evaluation the expression, then verify that it has the expected
        type. */
     inline bool evalBool(Env & env, Expr * e);
-    inline bool evalBool(Env & env, Expr * e, const PosIdx pos);
+    inline bool evalBool(Env & env, Expr * e, const Pos & pos);
     inline void evalAttrs(Env & env, Expr * e, Value & v);
 
     /* If `v' is a thunk, enter it and overwrite `v' with the result
        of the evaluation of the thunk.  If `v' is a delayed function
        application, call the function and overwrite `v' with the
        result.  Otherwise, this is a no-op. */
-    inline void forceValue(Value & v, const PosIdx pos);
+    inline void forceValue(Value & v, const Pos & pos);
 
     template <typename Callable>
     inline void forceValue(Value & v, Callable getPos);
@@ -300,103 +235,33 @@ public:
     void forceValueDeep(Value & v);
 
     /* Force `v', and then verify that it has the expected type. */
-    NixInt forceInt(Value & v, const PosIdx pos);
-    NixFloat forceFloat(Value & v, const PosIdx pos);
-    bool forceBool(Value & v, const PosIdx pos);
+    NixInt forceInt(Value & v, const Pos & pos);
+    NixFloat forceFloat(Value & v, const Pos & pos);
+    bool forceBool(Value & v, const Pos & pos);
 
-    void forceAttrs(Value & v, const PosIdx pos);
+    void forceAttrs(Value & v, const Pos & pos);
 
     template <typename Callable>
     inline void forceAttrs(Value & v, Callable getPos);
 
-    inline void forceList(Value & v, const PosIdx pos);
-    void forceFunction(Value & v, const PosIdx pos); // either lambda or primop
-    std::string_view forceString(Value & v, const PosIdx pos = noPos);
-    std::string_view forceString(Value & v, PathSet & context, const PosIdx pos = noPos);
-    std::string_view forceStringNoCtx(Value & v, const PosIdx pos = noPos);
+    inline void forceList(Value & v, const Pos & pos);
+    void forceFunction(Value & v, const Pos & pos); // either lambda or primop
+    std::string_view forceString(Value & v, const Pos & pos = noPos);
+    std::string_view forceString(Value & v, PathSet & context, const Pos & pos = noPos);
+    std::string_view forceStringNoCtx(Value & v, const Pos & pos = noPos);
 
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const char * s);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const char * s,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const char * s, const std::string & s2);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const char * s, const std::string & s2);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const char * s, const std::string & s2,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const char * s, const std::string & s2,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const char * s, const std::string & s2, const std::string & s3,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const char * s, const std::string & s2, const std::string & s3,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const char * s, const std::string & s2, const std::string & s3);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const char * s, const std::string & s2, const std::string & s3);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx pos, const Suggestions & suggestions, const char * s, const std::string & s2,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwEvalError(const PosIdx p1, const char * s, const Symbol sym, const PosIdx p2,
-        Env & env, Expr & expr);
-
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const PosIdx pos, const char * s, const Value & v);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const PosIdx pos, const char * s, const Value & v,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const PosIdx pos, const char * s);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const PosIdx pos, const char * s,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const PosIdx pos, const char * s, const ExprLambda & fun, const Symbol s2,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const PosIdx pos, const Suggestions & suggestions, const char * s, const ExprLambda & fun, const Symbol s2,
-        Env & env, Expr & expr);
-    [[gnu::noinline, gnu::noreturn]]
-    void throwTypeError(const char * s, const Value & v,
-        Env & env, Expr & expr);
-
-    [[gnu::noinline, gnu::noreturn]]
-    void throwAssertionError(const PosIdx pos, const char * s, const std::string & s1,
-        Env & env, Expr & expr);
-
-    [[gnu::noinline, gnu::noreturn]]
-    void throwUndefinedVarError(const PosIdx pos, const char * s, const std::string & s1,
-        Env & env, Expr & expr);
-
-    [[gnu::noinline, gnu::noreturn]]
-    void throwMissingArgumentError(const PosIdx pos, const char * s, const std::string & s1,
-        Env & env, Expr & expr);
-
-    [[gnu::noinline]]
-    void addErrorTrace(Error & e, const char * s, const std::string & s2) const;
-    [[gnu::noinline]]
-    void addErrorTrace(Error & e, const PosIdx pos, const char * s, const std::string & s2) const;
-
-public:
     /* Return true iff the value `v' denotes a derivation (i.e. a
        set with attribute `type = "derivation"'). */
     bool isDerivation(Value & v);
 
-    std::optional<std::string> tryAttrsToString(const PosIdx pos, Value & v,
+    std::optional<std::string> tryAttrsToString(const Pos & pos, Value & v,
         PathSet & context, bool coerceMore = false, bool copyToStore = true);
 
     /* String coercion.  Converts strings, paths and derivations to a
        string.  If `coerceMore' is set, also converts nulls, integers,
        booleans and lists to a string.  If `copyToStore' is set,
        referenced paths are copied to the Nix store as a side effect. */
-    BackedStringView coerceToString(const PosIdx pos, Value & v, PathSet & context,
+    BackedStringView coerceToString(const Pos & pos, Value & v, PathSet & context,
         bool coerceMore = false, bool copyToStore = true,
         bool canonicalizePath = true);
 
@@ -405,10 +270,10 @@ public:
     /* Path coercion.  Converts strings, paths and derivations to a
        path.  The result is guaranteed to be a canonicalised, absolute
        path.  Nothing is copied to the store. */
-    Path coerceToPath(const PosIdx pos, Value & v, PathSet & context);
+    Path coerceToPath(const Pos & pos, Value & v, PathSet & context);
 
     /* Like coerceToPath, but the result must be a store path. */
-    StorePath coerceToStorePath(const PosIdx pos, Value & v, PathSet & context);
+    StorePath coerceToStorePath(const Pos & pos, Value & v, PathSet & context);
 
 public:
 
@@ -417,7 +282,7 @@ public:
     Env & baseEnv;
 
     /* The same, but used during parsing to resolve variables. */
-    std::shared_ptr<StaticEnv> staticBaseEnv; // !!! should be private
+    StaticEnv staticBaseEnv; // !!! should be private
 
 private:
 
@@ -441,7 +306,7 @@ public:
     struct Doc
     {
         Pos pos;
-        std::optional<std::string> name;
+        std::optional<Symbol> name;
         size_t arity;
         std::vector<std::string> args;
         const char * doc;
@@ -458,7 +323,7 @@ private:
     friend struct ExprLet;
 
     Expr * parse(char * text, size_t length, FileOrigin origin, const PathView path,
-        const PathView basePath, std::shared_ptr<StaticEnv> & staticEnv);
+        const PathView basePath, StaticEnv & staticEnv);
 
 public:
 
@@ -469,9 +334,9 @@ public:
     bool isFunctor(Value & fun);
 
     // FIXME: use std::span
-    void callFunction(Value & fun, size_t nrArgs, Value * * args, Value & vRes, const PosIdx pos);
+    void callFunction(Value & fun, size_t nrArgs, Value * * args, Value & vRes, const Pos & pos);
 
-    void callFunction(Value & fun, Value & arg, Value & vRes, const PosIdx pos)
+    void callFunction(Value & fun, Value & arg, Value & vRes, const Pos & pos)
     {
         Value * args[] = {&arg};
         callFunction(fun, 1, args, vRes, pos);
@@ -482,10 +347,10 @@ public:
     void autoCallFunction(Bindings & args, Value & fun, Value & res);
 
     /* Allocation primitives. */
-    inline Value * allocValue();
-    inline Env & allocEnv(size_t size);
+    Value * allocValue();
+    Env & allocEnv(size_t size);
 
-    Value * allocAttr(Value & vAttrs, Symbol name);
+    Value * allocAttr(Value & vAttrs, const Symbol & name);
     Value * allocAttr(Value & vAttrs, std::string_view name);
 
     Bindings * allocBindings(size_t capacity);
@@ -497,9 +362,9 @@ public:
 
     void mkList(Value & v, size_t length);
     void mkThunk_(Value & v, Expr * expr);
-    void mkPos(Value & v, PosIdx pos);
+    void mkPos(Value & v, ptr<Pos> pos);
 
-    void concatLists(Value & v, size_t nrLists, Value * * lists, const PosIdx pos);
+    void concatLists(Value & v, size_t nrLists, Value * * lists, const Pos & pos);
 
     /* Print statistics. */
     void printStats();
@@ -527,7 +392,7 @@ private:
 
     bool countCalls;
 
-    typedef std::map<std::string, size_t> PrimOpCalls;
+    typedef std::map<Symbol, size_t> PrimOpCalls;
     PrimOpCalls primOpCalls;
 
     typedef std::map<ExprLambda *, size_t> FunctionCalls;
@@ -535,7 +400,7 @@ private:
 
     void incrFunctionCall(ExprLambda * fun);
 
-    typedef std::map<PosIdx, size_t> AttrSelects;
+    typedef std::map<Pos, size_t> AttrSelects;
     AttrSelects attrSelects;
 
     friend struct ExprOpUpdate;
@@ -546,23 +411,13 @@ private:
     friend struct ExprFloat;
     friend struct ExprPath;
     friend struct ExprSelect;
-    friend void prim_getAttr(EvalState & state, const PosIdx pos, Value * * args, Value & v);
-    friend void prim_match(EvalState & state, const PosIdx pos, Value * * args, Value & v);
-    friend void prim_split(EvalState & state, const PosIdx pos, Value * * args, Value & v);
+    friend void prim_getAttr(EvalState & state, const Pos & pos, Value * * args, Value & v);
+    friend void prim_match(EvalState & state, const Pos & pos, Value * * args, Value & v);
+    friend void prim_split(EvalState & state, const Pos & pos, Value * * args, Value & v);
 
     friend struct Value;
 };
 
-struct DebugTraceStacker {
-    DebugTraceStacker(EvalState & evalState, DebugTrace t);
-    ~DebugTraceStacker()
-    {
-        // assert(evalState.debugTraces.front() == trace);
-        evalState.debugTraces.pop_front();
-    }
-    EvalState & evalState;
-    DebugTrace trace;
-};
 
 /* Return a string representing the type of the value `v'. */
 std::string_view showType(ValueType type);
@@ -570,7 +425,7 @@ std::string showType(const Value & v);
 
 /* Decode a context string ‘!<name>!<path>’ into a pair <path,
    name>. */
-NixStringContextElem decodeContext(const Store & store, std::string_view s);
+std::pair<std::string, std::string> decodeContext(std::string_view s);
 
 /* If `path' refers to a directory, then append "/default.nix". */
 Path resolveExprPath(Path path);
@@ -647,15 +502,6 @@ struct EvalSettings : Config
 
     Setting<bool> useEvalCache{this, true, "eval-cache",
         "Whether to use the flake evaluation cache."};
-
-    Setting<bool> ignoreExceptionsDuringTry{this, false, "ignore-try",
-        R"(
-          If set to true, ignore exceptions inside 'tryEval' calls when evaluating nix expressions in
-          debug mode (using the --debugger flag). By default the debugger will pause on all exceptions.
-        )"};
-
-    Setting<bool> traceVerbose{this, false, "trace-verbose",
-        "Whether `builtins.traceVerbose` should trace its first argument when evaluated."};
 };
 
 extern EvalSettings evalSettings;
@@ -663,5 +509,3 @@ extern EvalSettings evalSettings;
 static const std::string corepkgsPrefix{"/__corepkgs__/"};
 
 }
-
-#include "eval-inline.hh"