Add aliases for the old flake commands

Requires reworking a bit the existing alias mechanism to allow aliases to be composite commands themselves
Move nix flake {new,init} at toplevel
2021-11-25 21:42:55 +01:00 · 2021-11-25 21:42:55 +01:00
225 changed files with 5412 additions and 16189 deletions
@@ -1,7 +0,0 @@
-**Release Notes**
-Please include relevant [release notes](https://github.com/NixOS/nix/blob/master/doc/manual/src/release-notes/rl-next.md) as needed.
-
-
-**Testing**
-
-If this issue is a regression or something that should block release, please consider including a test either in the [testsuite](https://github.com/NixOS/nix/tree/master/tests) or as a [hydraJob]( https://github.com/NixOS/nix/blob/master/flake.nix#L396) so that it can be part of the [automatic checks](https://hydra.nixos.org/jobset/nix/master).
@@ -1,16 +0,0 @@
-name: Hydra status
-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@v2.4.0
-      with:
-        fetch-depth: 0
-    - run: bash scripts/check-hydra-status.sh
-
@@ -1,4 +1,4 @@
-name: "CI"
+name: "Test"

 on:
  pull_request:
@@ -74,35 +74,3 @@ jobs:
        install_url: '${{needs.installer.outputs.installerURL}}'
        install_options: "--tarball-url-prefix https://${{ env.CACHIX_NAME }}.cachix.org/serve"
    - run: nix-instantiate -E 'builtins.currentTime' --eval
-
-  docker_push_image:
-    needs: [check_cachix, tests]
-    if: >-
-      github.event_name == 'push' &&
-      github.ref_name == 'master' &&
-      needs.check_cachix.outputs.secret == 'true'
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2.4.0
-      with:
-        fetch-depth: 0
-    - 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-instantiate --eval -E '(import ./default.nix).defaultPackage.${builtins.currentSystem}.version' | tr -d \")" >> $GITHUB_ENV
-    - uses: cachix/cachix-action@v10
-      if: needs.check_cachix.outputs.secret == 'true'
-      with:
-        name: '${{ env.CACHIX_NAME }}'
-        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
-        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
-    - run: nix-build -A checks.$(nix-instantiate --eval -E 'builtins.currentSystem' --json).dockerImage
-    - run: docker load -i ./result/image.tar.gz
-    - run: docker tag nix:$NIX_VERSION nixos/nix:$NIX_VERSION
-    - run: docker tag nix:$NIX_VERSION nixos/nix:master
-    - name: Login to Docker Hub
-      uses: docker/login-action@v1
-      with:
-        username: ${{ secrets.DOCKERHUB_USERNAME }}
-        password: ${{ secrets.DOCKERHUB_TOKEN }}
-    - run: docker push nixos/nix:$NIX_VERSION
-    - run: docker push nixos/nix:master
@@ -1 +1 @@
-2.6.1
+2.5
@@ -10,7 +10,6 @@ makefiles = \
  src/libexpr/local.mk \
  src/libcmd/local.mk \
  src/nix/local.mk \
-  src/nlohmann/local.mk \
  src/resolve-system-dependencies/local.mk \
  scripts/local.mk \
  misc/bash/local.mk \
@@ -188,24 +188,17 @@ PKG_CHECK_MODULES([EDITLINE], [libeditline], [CXXFLAGS="$EDITLINE_CFLAGS $CXXFLA
    [AC_MSG_ERROR([Nix requires libeditline; it was not found via pkg-config, but via its header, but required functions do not work. Maybe it is too old? >= 1.14 is required.])])
 ])

-# Look for libsodium.
+# Look for libsodium, an optional dependency.
 PKG_CHECK_MODULES([SODIUM], [libsodium], [CXXFLAGS="$SODIUM_CFLAGS $CXXFLAGS"])

 # Look for libbrotli{enc,dec}.
 PKG_CHECK_MODULES([LIBBROTLI], [libbrotlienc libbrotlidec], [CXXFLAGS="$LIBBROTLI_CFLAGS $CXXFLAGS"])

 # Look for libcpuid.
-have_libcpuid=
 if test "$machine_name" = "x86_64"; then
-    AC_ARG_ENABLE([cpuid],
-                  AS_HELP_STRING([--disable-cpuid], [Do not determine microarchitecture levels with libcpuid (relevant to x86_64 only)]))
-    if test "x$enable_cpuid" != "xno"; then
-      PKG_CHECK_MODULES([LIBCPUID], [libcpuid],
-        [CXXFLAGS="$LIBCPUID_CFLAGS $CXXFLAGS"
-         have_libcpuid=1
-         AC_DEFINE([HAVE_LIBCPUID], [1], [Use libcpuid])]
-      )
-    fi
+  PKG_CHECK_MODULES([LIBCPUID], [libcpuid], [CXXFLAGS="$LIBCPUID_CFLAGS $CXXFLAGS"])
+  have_libcpuid=1
+  AC_DEFINE([HAVE_LIBCPUID], [1], [Use libcpuid])
 fi
 AC_SUBST(HAVE_LIBCPUID, [$have_libcpuid])

@@ -8,19 +8,17 @@ concatStrings (map
    let option = options.${name}; in
    "  - `${name}`  \n\n"
    + concatStrings (map (s: "    ${s}\n") (splitLines option.description)) + "\n\n"
-    + (if option.documentDefault
-       then "    **Default:** " + (
-       if option.value == "" || option.value == []
-       then "*empty*"
-       else if isBool option.value
-       then (if option.value then "`true`" else "`false`")
-       else
-         # n.b. a StringMap value type is specified as a string, but
-         # this shows the value type.  The empty stringmap is "null" in
-         # JSON, but that converts to "{ }" here.
-         (if isAttrs option.value then "`\"\"`"
-          else "`" + toString option.value + "`")) + "\n\n"
-       else "    **Default:** *machine-specific*")
+    + "    **Default:** " + (
+      if option.value == "" || option.value == []
+      then "*empty*"
+      else if isBool option.value
+      then (if option.value then "`true`" else "`false`")
+      else
+        # n.b. a StringMap value type is specified as a string, but
+        # this shows the value type.  The empty stringmap is "null" in
+        # JSON, but that converts to "{ }" here.
+        (if isAttrs option.value then "`\"\"`"
+         else "`" + toString option.value + "`")) + "\n\n"
    + (if option.aliases != []
       then "    **Deprecated alias:** " + (concatStringsSep ", " (map (s: "`${s}`") option.aliases)) + "\n\n"
       else "")
@@ -12,13 +12,11 @@ man-pages := $(foreach n, \
 clean-files += $(d)/*.1 $(d)/*.5 $(d)/*.8

 # Provide a dummy environment for nix, so that it will not access files outside the macOS sandbox.
-# Set cores to 0 because otherwise nix show-config resolves the cores based on the current machine
 dummy-env = env -i \
 	HOME=/dummy \
 	NIX_CONF_DIR=/dummy \
 	NIX_SSL_CERT_FILE=/dummy/no-ca-bundle.crt \
-	NIX_STATE_DIR=/dummy \
-	NIX_CONFIG='cores = 0'
+	NIX_STATE_DIR=/dummy

 nix-eval = $(dummy-env) $(bindir)/nix eval --experimental-features nix-command -I nix/corepkgs=corepkgs --store dummy:// --impure --raw

@@ -71,8 +71,7 @@
  - [Hacking](contributing/hacking.md)
  - [CLI guideline](contributing/cli-guideline.md)
 - [Release Notes](release-notes/release-notes.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)
+  - [Release X.Y (202?-??-??)](release-notes/rl-next.md)
  - [Release 2.4 (2021-11-01)](release-notes/rl-2.4.md)
  - [Release 2.3 (2019-09-04)](release-notes/rl-2.3.md)
  - [Release 2.2 (2019-01-11)](release-notes/rl-2.2.md)
@@ -53,8 +53,8 @@ example, the following command allows you to build a derivation for
 $ uname
 Linux

-$ nix build --impure \
-  --expr '(with import <nixpkgs> { system = "x86_64-darwin"; }; runCommand "foo" {} "uname > $out")' \
+$ nix build \
+  '(with import <nixpkgs> { system = "x86_64-darwin"; }; runCommand "foo" {} "uname > $out")' \
  --builders 'ssh://mac x86_64-darwin'
 [1/0/1 built, 0.0 MiB DL] building foo on ssh://mac

@@ -101,8 +101,7 @@ The following common options are supported:

  - `NIX_BUILD_SHELL`\
    Shell used to start the interactive environment. Defaults to the
-    `bash` found in `<nixpkgs>`, falling back to the `bash` found in
-    `PATH` if not found.
+    `bash` found in `PATH`.

 # Examples

@@ -35,25 +35,6 @@ variables are set up so that those dependencies can be found:
 $ nix-shell
 ```

-or if you have a flake-enabled nix:
-
-```console
-$ nix develop
-```
-
-To get a shell with a different compilation environment (e.g. stdenv,
-gccStdenv, clangStdenv, clang11Stdenv):
-
-```console
-$ nix-shell -A devShells.x86_64-linux.clang11StdenvPackages
-```
-
-or if you have a flake-enabled nix:
-
-```console
-$ nix develop .#clang11StdenvPackages
-```
-
 To build Nix itself in this shell:

 ```console
@@ -284,10 +284,6 @@ The points of interest are:
    function is called with the `localServer` argument set to `true` but
    the `db4` argument set to `null`, then the evaluation fails.

-    Note that `->` is the [logical
-    implication](https://en.wikipedia.org/wiki/Truth_table#Logical_implication)
-    Boolean operation.
-
 2.  This is a more subtle condition: if Subversion is built with Apache
    (`httpServer`) support, then the Expat library (an XML library) used
    by Subversion should be same as the one used by Apache. This is
@@ -47,7 +47,7 @@
    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
    has a reference.
-
+    
    A derivation can reference other derivations and sources (but not
    output paths), whereas an output path only references other output
    paths.
@@ -66,7 +66,7 @@
    is necessary to deploy whole closures, since otherwise at runtime
    files could be missing. The command `nix-store -qR` prints out
    closures of store paths.
-
+    
    As an example, if the store object at path `P` contains a reference
    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`.
@@ -98,7 +98,3 @@
    store. It can contain regular files, directories and symbolic
    links.  NARs are generated and unpacked using `nix-store --dump`
    and `nix-store --restore`.
-  - `∅` \
-    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` \
-    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.
@@ -119,30 +119,6 @@ this to run the installer, but it may help if you run into trouble:
 - update `/etc/synthetic.conf` to direct macOS to create a "synthetic"
  empty root directory to mount your volume
 - specify mount options for the volume in `/etc/fstab`
-  - `rw`: read-write
-  - `noauto`: prevent the system from auto-mounting the volume (so the
-    LaunchDaemon mentioned below can control mounting it, and to avoid
-    masking problems with that mounting service).
-  - `nobrowse`: prevent the Nix Store volume from showing up on your
-    desktop; also keeps Spotlight from spending resources to index
-    this volume
-  <!-- TODO:
-  - `suid`: honor setuid? surely not? ...
-  - `owners`: honor file ownership on the volume
-
-    For now I'll avoid pretending to understand suid/owners more
-    than I do. There've been some vague reports of file-ownership
-    and permission issues, particularly in cloud/VM/headless setups.
-    My pet theory is that this has something to do with these setups
-    not having a token that gets delegated to initial/admin accounts
-    on macOS. See scripts/create-darwin-volume.sh for a little more.
-
-    In any case, by Dec 4 2021, it _seems_ like some combination of
-    suid, owners, and calling diskutil enableOwnership have stopped
-    new reports from coming in. But I hesitate to celebrate because we
-    haven't really named and catalogued the behavior, understood what
-    we're fixing, and validated that all 3 components are essential.
-  -->
 - if you have FileVault enabled
    - generate an encryption password
    - put it in your system Keychain
@@ -3,7 +3,7 @@
 To run the latest stable release of Nix with Docker run the following command:

 ```console
-$ docker run -ti nixos/nix
+$ docker -ti run nixos/nix
 Unable to find image 'nixos/nix:latest' locally
 latest: Pulling from nixos/nix
 5843afab3874: Pull complete
@@ -16,7 +16,7 @@ nix (Nix) 2.3.12
 35ca4ada6e96:/# exit
 ```

-# What is included in Nix's Docker image?
+# What is included in Nix' Docker image?

 The official Docker image is created using `pkgs.dockerTools.buildLayeredImage`
 (and not with `Dockerfile` as it is usual with Docker images). You can still
@@ -54,6 +54,6 @@ You can also build a Docker image from source yourself:

 ```console
 $ nix build ./\#hydraJobs.dockerImage.x86_64-linux
-$ docker load -i ./result/image.tar.gz
+$ docker load -i ./result
 $ docker run -ti nix:2.5pre20211105
 ```
@@ -44,11 +44,6 @@
    obtained from the its repository
    <https://github.com/troglobit/editline>.

-  - The `libsodium` library for verifying cryptographic signatures
-    of contents fetched from binary caches.
-    It can be obtained from the official web site
-    <https://libsodium.org>.
-
  - Recent versions of Bison and Flex to build the parser. (This is
    because Nix needs GLR support in Bison and reentrancy support in
    Flex.) For Bison, you need version 2.6, which can be obtained from
@@ -63,11 +58,3 @@
    `--disable-seccomp-sandboxing` option to the `configure` script (Not
    recommended unless your system doesn't support `libseccomp`). To get
    the library, visit <https://github.com/seccomp/libseccomp>.
-
-  - On 64-bit x86 machines only, `libcpuid` library
-    is used to determine which microarchitecture levels are supported
-    (e.g., as whether to have `x86_64-v2-linux` among additional system types).
-    The library is available from its homepage
-    <http://libcpuid.sourceforge.net>.
-    This is an optional dependency and can be disabled
-    by providing a `--disable-cpuid` to the `configure` script.
@@ -4,4 +4,4 @@ Nix is currently supported on the following platforms:

  - Linux (i686, x86\_64, aarch64).

-  - macOS (x86\_64, aarch64).
+  - macOS (x86\_64).
@@ -40,7 +40,7 @@ $ nix-channel --update
 > 
 > On NixOS, you’re automatically subscribed to a NixOS channel
 > corresponding to your NixOS major release (e.g.
-> <http://nixos.org/channels/nixos-21.11>). A NixOS channel is identical
+> <http://nixos.org/channels/nixos-14.12>). A NixOS channel is identical
 > to the Nixpkgs channel, except that it contains only Linux binaries
 > and is updated only if a set of regression tests succeed.

@@ -276,9 +276,6 @@ more than 2800 commits from 195 contributors since release 2.3.

 * Plugins can now register `nix` subcommands.

-* The `--indirect` flag to `nix-store --add-root` has become a no-op.
-  `--add-root` will always generate indirect GC roots from now on.
-
 ## Incompatible changes

 * The `nix` command is now marked as an experimental feature. This
@@ -1,16 +0,0 @@
-# Release 2.5 (2021-12-13)
-
-* The garbage collector no longer blocks new builds, so the message
-  `waiting for the big garbage collector lock...` is a thing of the
-  past.
-
-* Binary cache stores now have a setting `compression-level`.
-
-* `nix develop` now has a flag `--unpack` to run `unpackPhase`.
-
-* Lists can now be compared lexicographically using the `<` operator.
-
-* New built-in function: `builtins.groupBy`, with the same functionality as
-  Nixpkgs' `lib.groupBy`, but faster.
-
-* `nix repl` now has a `:log` command.
@@ -1,21 +0,0 @@
-# Release 2.6 (2022-01-24)
-
-* The Nix CLI now searches for a `flake.nix` up until the root of the current
-  Git repository or a filesystem boundary rather than just in the current
-  directory.
-* The TOML parser used by `builtins.fromTOML` has been replaced by [a
-  more compliant one](https://github.com/ToruNiina/toml11).
-* Added `:st`/`:show-trace` commands to `nix repl`, which are used to
-  set or toggle display of error traces.
-* New builtin function `builtins.zipAttrsWith` with the same
-  functionality as `lib.zipAttrsWith` from Nixpkgs, but much more
-  efficient.
-* New command `nix store copy-log` to copy build logs from one store
-  to another.
-* The `commit-lockfile-summary` option can be set to a non-empty
-  string to override the commit summary used when commiting an updated
-  lockfile.  This may be used in conjunction with the `nixConfig`
-  attribute in `flake.nix` to better conform to repository
-  conventions.
-* `docker run -ti nixos/nix:master` will place you in the Docker
-  container with the latest version of Nix from the `master` branch.
@@ -1,2 +1,7 @@
-# Release X.Y (202?-??-??)
+# Release 2.5 (2021-XX-XX)

+* Binary cache stores now have a setting `compression-level`.
+
+* `nix develop` now has a flag `--unpack` to run `unpackPhase`.
+
+* Lists can now be compared lexicographically using the `<` operator.
@@ -20,8 +20,6 @@ let
    man
    cacert.out
    findutils
-    iana-etc
-    git
  ];

  users = {
@@ -139,8 +137,11 @@ let
        name = "root-profile-env";
        paths = defaultPkgs;
      };
-      manifest = pkgs.buildPackages.runCommand "manifest.nix" { } ''
-        cat > $out <<EOF
+      profile = pkgs.buildPackages.runCommand "user-environment" { } ''
+        mkdir $out
+        cp -a ${rootEnv}/* $out/
+
+        cat > $out/manifest.nix <<EOF
        [
        ${lib.concatStringsSep "\n" (builtins.map (drv: let
          outputs = drv.outputsToInstall or [ "out" ];
@@ -160,11 +161,6 @@ let
        ]
        EOF
      '';
-      profile = pkgs.buildPackages.runCommand "user-environment" { } ''
-        mkdir $out
-        cp -a ${rootEnv}/* $out/
-        ln -s ${manifest} $out/manifest.nix
-      '';
    in
    pkgs.runCommand "base-system"
      {
@@ -182,9 +178,6 @@ let
      set -x
      mkdir -p $out/etc

-      mkdir -p $out/etc/ssl/certs
-      ln -s /nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt $out/etc/ssl/certs
-
      cat $passwdContentsPath > $out/etc/passwd
      echo "" >> $out/etc/passwd

@@ -201,8 +194,6 @@ let

      mkdir $out/tmp

-      mkdir -p $out/var/tmp
-
      mkdir -p $out/etc/nix
      cat $nixConfContentsPath > $out/etc/nix/nix.conf

@@ -236,10 +227,6 @@ pkgs.dockerTools.buildLayeredImageWithNixDb {
    rm -rf nix-support
    ln -s /nix/var/nix/profiles nix/var/nix/gcroots/profiles
  '';
-  fakeRootCommands = ''
-    chmod 1777 tmp
-    chmod 1777 var/tmp
-  '';

  config = {
    Cmd = [ "/root/.nix-profile/bin/bash" ];
@@ -31,26 +31,10 @@
        "type": "indirect"
      }
    },
-    "nixpkgs-regression": {
-      "locked": {
-        "lastModified": 1643052045,
-        "narHash": "sha256-uGJ0VXIhWKGXxkeNnq4TvV3CIOkUJ3PAoLZ3HMzNVMw=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
-        "type": "github"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "rev": "215d4d0fd80ca5163643b03a33fde804a29cc1e2",
-        "type": "indirect"
-      }
-    },
    "root": {
      "inputs": {
        "lowdown-src": "lowdown-src",
-        "nixpkgs": "nixpkgs",
-        "nixpkgs-regression": "nixpkgs-regression"
+        "nixpkgs": "nixpkgs"
      }
    }
  },
@@ -2,10 +2,9 @@
  description = "The purely functional package manager";

  inputs.nixpkgs.url = "nixpkgs/nixos-21.05-small";
-  inputs.nixpkgs-regression.url = "nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2";
  inputs.lowdown-src = { url = "github:kristapsdz/lowdown"; flake = false; };

-  outputs = { self, nixpkgs, nixpkgs-regression, lowdown-src }:
+  outputs = { self, nixpkgs, lowdown-src }:

    let

@@ -15,7 +14,7 @@
        then ""
        else "pre${builtins.substring 0 8 (self.lastModifiedDate or self.lastModified or "19700101")}_${self.shortRev or "dirty"}";

-      officialRelease = true;
+      officialRelease = false;

      linux64BitSystems = [ "x86_64-linux" "aarch64-linux" ];
      linuxSystems = linux64BitSystems ++ [ "i686-linux" ];
@@ -23,36 +22,15 @@

      crossSystems = [ "armv6l-linux" "armv7l-linux" ];

-      stdenvs = [ "gccStdenv" "clangStdenv" "clang11Stdenv" "stdenv" ];
-
      forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
-      forAllSystemsAndStdenvs = f: forAllSystems (system:
-        nixpkgs.lib.listToAttrs
-          (map
-            (n:
-            nixpkgs.lib.nameValuePair "${n}Packages" (
-              f system n
-            )) stdenvs
-          )
-      );
-
-      forAllStdenvs = stdenvs: f: nixpkgs.lib.genAttrs stdenvs (stdenv: f stdenv);

      # Memoize nixpkgs for different platforms for efficiency.
-      nixpkgsFor =
-        let stdenvsPackages = forAllSystemsAndStdenvs
-          (system: stdenv:
-            import nixpkgs {
-              inherit system;
-              overlays = [
-                (overlayFor (p: p.${stdenv}))
-              ];
-            }
-          );
-        in
-        # Add the `stdenvPackages` at toplevel, both because these are the ones
-        # we want most of the time and for backwards compatibility
-        forAllSystems (system: stdenvsPackages.${system} // stdenvsPackages.${system}.stdenvPackages);
+      nixpkgsFor = forAllSystems (system:
+        import nixpkgs {
+          inherit system;
+          overlays = [ self.overlay ];
+        }
+      );

      commonDeps = pkgs: with pkgs; rec {
        # Use "busybox-sandbox-shell" if present,
@@ -97,7 +75,7 @@
            buildPackages.mdbook
            buildPackages.autoconf-archive
            buildPackages.autoreconfHook
-            buildPackages.pkg-config
+            buildPackages.pkgconfig

            # Tests
            buildPackages.git
@@ -277,15 +255,18 @@
            $(cat ${installerClosureInfo}/store-paths)
        '';

-      overlayFor = getStdenv: final: prev:
-      let currentStdenv = getStdenv final; in
-      {
+    in {
+
+      # A Nixpkgs overlay that overrides the 'nix' and
+      # 'nix.perl-bindings' packages.
+      overlay = final: prev: {
+
        nixStable = prev.nix;

        # Forward from the previous stage as we don’t want it to pick the lowdown override
        nixUnstable = prev.nixUnstable;

-        nix = with final; with commonDeps pkgs; currentStdenv.mkDerivation {
+        nix = with final; with commonDeps pkgs; stdenv.mkDerivation {
          name = "nix-${version}";
          inherit version;

@@ -300,8 +281,6 @@

          propagatedBuildInputs = propagatedDeps;

-          disallowedReferences = [ boost ];
-
          preConfigure =
            ''
              # Copy libboost_context so we don't get all of Boost in our closure.
@@ -309,16 +288,9 @@
              mkdir -p $out/lib
              cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*} $out/lib
              rm -f $out/lib/*.a
-              ${lib.optionalString currentStdenv.isLinux ''
+              ${lib.optionalString stdenv.isLinux ''
                chmod u+w $out/lib/*.so.*
-                patchelf --set-rpath $out/lib:${currentStdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
-              ''}
-              ${lib.optionalString currentStdenv.isDarwin ''
-                for LIB in $out/lib/*.dylib; do
-                  chmod u+w $LIB
-                  install_name_tool -id $LIB $LIB
-                done
-                install_name_tool -change ${boost}/lib/libboost_system.dylib $out/lib/libboost_system.dylib $out/lib/libboost_thread.dylib
+                patchelf --set-rpath $out/lib:${stdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
              ''}
            '';

@@ -336,12 +308,6 @@
          postInstall = ''
            mkdir -p $doc/nix-support
            echo "doc manual $doc/share/doc/nix/manual" >> $doc/nix-support/hydra-build-products
-            ${lib.optionalString currentStdenv.isDarwin ''
-            install_name_tool \
-              -change ${boost}/lib/libboost_context.dylib \
-              $out/lib/libboost_context.dylib \
-              $out/lib/libnixutil.dylib
-            ''}
          '';

          doInstallCheck = true;
@@ -351,7 +317,7 @@

          strictDeps = true;

-          passthru.perl-bindings = with final; currentStdenv.mkDerivation {
+          passthru.perl-bindings = with final; stdenv.mkDerivation {
            name = "nix-perl-${version}";

            src = self;
@@ -359,7 +325,7 @@
            nativeBuildInputs =
              [ buildPackages.autoconf-archive
                buildPackages.autoreconfHook
-                buildPackages.pkg-config
+                buildPackages.pkgconfig
              ];

            buildInputs =
@@ -370,8 +336,8 @@
                pkgs.perl
                boost
              ]
-              ++ lib.optional (currentStdenv.isLinux || currentStdenv.isDarwin) libsodium
-              ++ lib.optional currentStdenv.isDarwin darwin.apple_sdk.frameworks.Security;
+              ++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium
+              ++ lib.optional stdenv.isDarwin darwin.apple_sdk.frameworks.Security;

            configureFlags = ''
              --with-dbi=${perlPackages.DBI}/${pkgs.perl.libPrefix}
@@ -385,7 +351,7 @@

        };

-        lowdown-nix = with final; currentStdenv.mkDerivation rec {
+        lowdown-nix = with final; stdenv.mkDerivation rec {
          name = "lowdown-0.9.0";

          src = lowdown-src;
@@ -395,20 +361,15 @@
          nativeBuildInputs = [ buildPackages.which ];

          configurePhase = ''
-              ${if (currentStdenv.isDarwin && currentStdenv.isAarch64) then "echo \"HAVE_SANDBOX_INIT=false\" > configure.local" else ""}
+              ${if (stdenv.isDarwin && stdenv.isAarch64) then "echo \"HAVE_SANDBOX_INIT=false\" > configure.local" else ""}
              ./configure \
                PREFIX=${placeholder "dev"} \
                BINDIR=${placeholder "bin"}/bin
-          '';
+            '';
        };
+
      };

-    in {
-
-      # A Nixpkgs overlay that overrides the 'nix' and
-      # 'nix.perl-bindings' packages.
-      overlay = overlayFor (p: p.stdenv);
-
      hydraJobs = {

        # Binary package for various platforms.
@@ -519,23 +480,29 @@
              inherit (self) overlay;
            });

-        # Make sure that nix-env still produces the exact same result
-        # on a particular version of Nixpkgs.
+        /*
+        # Check whether we can still evaluate all of Nixpkgs.
        tests.evalNixpkgs =
+          import (nixpkgs + "/pkgs/top-level/make-tarball.nix") {
+            # FIXME: fix pkgs/top-level/make-tarball.nix in NixOS to not require a revCount.
+            inherit nixpkgs;
+            pkgs = nixpkgsFor.x86_64-linux;
+            officialRelease = false;
+          };
+
+        # Check whether we can still evaluate NixOS.
+        tests.evalNixOS =
          with nixpkgsFor.x86_64-linux;
          runCommand "eval-nixos" { buildInputs = [ nix ]; }
            ''
-              type -p nix-env
-              # Note: we're filtering out nixos-install-tools because https://github.com/NixOS/nixpkgs/pull/153594#issuecomment-1020530593.
-              time nix-env --store dummy:// -f ${nixpkgs-regression} -qaP --drv-path | sort | grep -v nixos-install-tools > packages
-              [[ $(sha1sum < packages | cut -c1-40) = ff451c521e61e4fe72bdbe2d0ca5d1809affa733 ]]
-              mkdir $out
-            '';
+              export NIX_STATE_DIR=$TMPDIR

-        metrics.nixpkgs = import "${nixpkgs-regression}/pkgs/top-level/metrics.nix" {
-          pkgs = nixpkgsFor.x86_64-linux;
-          nixpkgs = nixpkgs-regression;
-        };
+              nix-instantiate ${nixpkgs}/nixos/release-combined.nix -A tested --dry-run \
+                --arg nixpkgs '{ outPath = ${nixpkgs}; revCount = 123; shortRev = "abcdefgh"; }'
+
+              touch $out
+            '';
+        */

        installTests = forAllSystems (system:
          let pkgs = nixpkgsFor.${system}; in
@@ -557,9 +524,9 @@
        binaryTarball = self.hydraJobs.binaryTarball.${system};
        perlBindings = self.hydraJobs.perlBindings.${system};
        installTests = self.hydraJobs.installTests.${system};
-      } // (nixpkgs.lib.optionalAttrs (builtins.elem system linux64BitSystems)) {
+      } // (if system == "x86_64-linux" then {
        dockerImage = self.hydraJobs.dockerImage.${system};
-      });
+      } else {}));

      packages = forAllSystems (system: {
        inherit (nixpkgsFor.${system}) nix;
@@ -643,22 +610,15 @@
          doInstallCheck = true;
          installCheckFlags = "sysconfdir=$(out)/etc";
        };
-      }) crossSystems)) // (builtins.listToAttrs (map (stdenvName:
-      nixpkgsFor.${system}.lib.nameValuePair
-        "nix-${stdenvName}"
-        nixpkgsFor.${system}."${stdenvName}Packages".nix
-      ) stdenvs))
-      );
+      }) crossSystems)));

      defaultPackage = forAllSystems (system: self.packages.${system}.nix);

-      devShell = forAllSystems (system: self.devShells.${system}.stdenvPackages);
-
-      devShells = forAllSystemsAndStdenvs (system: stdenv:
+      devShell = forAllSystems (system:
        with nixpkgsFor.${system};
        with commonDeps pkgs;

-        nixpkgsFor.${system}.${stdenv}.mkDerivation {
+        stdenv.mkDerivation {
          name = "nix";

          outputs = [ "out" "dev" "doc" ];
@@ -677,9 +637,6 @@
              PATH=$prefix/bin:$PATH
              unset PYTHONPATH
              export MANPATH=$out/share/man:$MANPATH
-
-              # Make bash completion work.
-              XDG_DATA_DIRS+=:$out/share
            '';
        });

@@ -7,15 +7,13 @@ function _complete_nix {
        local completion=${line%%	*}
        if [[ -z $have_type ]]; then
            have_type=1
-            if [[ $completion == filenames ]]; then
+            if [[ $completion = filenames ]]; then
                compopt -o filenames
-            elif [[ $completion == attrs ]]; then
-                compopt -o nospace
            fi
        else
            COMPREPLY+=("$completion")
        fi
-    done < <(NIX_GET_COMPLETIONS=$cword "${words[@]/#\~/$HOME}")
+    done < <(NIX_GET_COMPLETIONS=$cword "${words[@]}")
    __ltrim_colon_completions "$cur"
 }

@@ -19,6 +19,7 @@ end

 function _nix_accepts_files
  set -l response (_nix_complete)
+  # First line is either filenames or no-filenames.
  test $response[1] = 'filenames'
 end

@@ -25,10 +25,5 @@
    <string>/var/log/nix-daemon.log</string>
    <key>StandardOutPath</key>
    <string>/dev/null</string>
-    <key>SoftResourceLimits</key>
-    <dict>
-      <key>NumberOfFiles</key>
-      <integer>4096</integer>
-    </dict>
  </dict>
 </plist>
@@ -41,7 +41,7 @@ perlarchname=$($perl -e 'use Config; print $Config{archname};')
 AC_SUBST(perllibdir, [${libdir}/perl5/site_perl/$perlversion/$perlarchname])
 AC_MSG_RESULT($perllibdir)

-# Look for libsodium.
+# Look for libsodium, an optional dependency.
 PKG_CHECK_MODULES([SODIUM], [libsodium], [CXXFLAGS="$SODIUM_CFLAGS $CXXFLAGS"])

 # Check for the required Perl dependencies (DBI and DBD::SQLite).
@@ -1,28 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-# set -x
-
-
-# mapfile BUILDS_FOR_LATEST_EVAL < <(
-# curl -H 'Accept: application/json' https://hydra.nixos.org/jobset/nix/master/evals | \
-#   jq -r '.evals[0].builds[] | @sh')
-BUILDS_FOR_LATEST_EVAL=$(
-curl -sS -H 'Accept: application/json' https://hydra.nixos.org/jobset/nix/master/evals | \
-  jq -r '.evals[0].builds[]')
-
-someBuildFailed=0
-
-for buildId in $BUILDS_FOR_LATEST_EVAL; do
-  buildInfo=$(curl -sS -H 'Accept: application/json' "https://hydra.nixos.org/build/$buildId")
-
-  buildStatus=$(echo "$buildInfo" | \
-    jq -r '.buildstatus')
-
-  if [[ "$buildStatus" -ne 0 ]]; then
-    someBuildFailed=1
-    echo "Job “$(echo "$buildInfo" | jq -r '.job')” failed on hydra"
-  fi
-done
-
-exit "$someBuildFailed"
@@ -440,22 +440,7 @@ add_nix_vol_fstab_line() {
    # shellcheck disable=SC1003,SC2026
    local escaped_mountpoint="${NIX_ROOT/ /'\\\'040}"
    shift
-
-    # 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
-    # until https://github.com/vim/vim/releases/tag/v8.0.1554 while the macOS
-    # minver 10.12.6 seems to have released with vim 7.4
-    cat > "$SCRATCH/ex_cleanroom_wrapper" <<EOF
-#!/bin/sh
-/usr/bin/ex --noplugin "\$@"
-EOF
-    chmod 755 "$SCRATCH/ex_cleanroom_wrapper"
-
-    EDITOR="$SCRATCH/ex_cleanroom_wrapper" _sudo "to add nix to fstab" "$@" <<EOF
+    EDITOR="/usr/bin/ex" _sudo "to add nix to fstab" "$@" <<EOF
 :a
 UUID=$uuid $escaped_mountpoint apfs rw,noauto,nobrowse,suid,owners
 .
@@ -646,7 +631,7 @@ EOF
        # technically /etc/synthetic.d/nix is supported in Big Sur+
        # but handling both takes even more code...
        _sudo "to add Nix to /etc/synthetic.conf" \
-            /usr/bin/ex --noplugin /etc/synthetic.conf <<EOF
+            /usr/bin/ex /etc/synthetic.conf <<EOF
 :a
 ${NIX_ROOT:1}
 .
@@ -809,7 +794,7 @@ setup_volume_daemon() {
    local volume_uuid="$2"
    if ! test_voldaemon; then
        task "Configuring LaunchDaemon to mount '$NIX_VOLUME_LABEL'" >&2
-        _sudo "to install the Nix volume mounter" /usr/bin/ex --noplugin "$NIX_VOLUME_MOUNTD_DEST" <<EOF
+        _sudo "to install the Nix volume mounter" /usr/bin/ex "$NIX_VOLUME_MOUNTD_DEST" <<EOF
 :a
 $(generate_mount_daemon "$cmd_type" "$volume_uuid")
 .
@@ -218,7 +218,7 @@ EOF
        setup_darwin_volume
    fi

-    if [ "$(/usr/sbin/diskutil info -plist /nix | xmllint --xpath "(/plist/dict/key[text()='GlobalPermissionsEnabled'])/following-sibling::*[1]" -)" = "<false/>" ]; then
-        failure "This script needs a /nix volume with global permissions! This may require running sudo /usr/sbin/diskutil enableOwnership /nix."
+    if [ "$(diskutil info -plist /nix | xmllint --xpath "(/plist/dict/key[text()='GlobalPermissionsEnabled'])/following-sibling::*[1]" -)" = "<false/>" ]; then
+        failure "This script needs a /nix volume with global permissions! This may require running sudo diskutil enableOwnership /nix."
    fi
 }
@@ -377,11 +377,6 @@ cure_artifacts() {
 }

 validate_starting_assumptions() {
-    task "Checking for artifacts of previous installs"
-    cat <<EOF
-Before I try to install, I'll check for signs Nix already is or has
-been installed on this system.
-EOF
    if type nix-env 2> /dev/null >&2; then
        warning <<EOF
 Nix already appears to be installed. This installer may run into issues.
@@ -391,11 +386,6 @@ $(uninstall_directions)
 EOF
    fi

-    # TODO: I think it would be good for this step to accumulate more
-    #       knowledge of older obsolete artifacts, if there are any.
-    #       We could issue a "reminder" here that the user might want
-    #       to clean them up?
-
    for profile_target in "${PROFILE_TARGETS[@]}"; do
        # TODO: I think it would be good to accumulate a list of all
        #       of the copies so that people don't hit this 2 or 3x in
@@ -590,7 +580,7 @@ create_directories() {
              "$get_chr_own" -R "root:$NIX_BUILD_GROUP_NAME" "$NIX_ROOT" || true
    fi
    _sudo "to make the basic directory structure of Nix (part 1)" \
-          install -dv -m 0755 /nix /nix/var /nix/var/log /nix/var/log/nix /nix/var/log/nix/drvs /nix/var/nix{,/db,/gcroots,/profiles,/temproots,/userpool,/daemon-socket} /nix/var/nix/{gcroots,profiles}/per-user
+          install -dv -m 0755 /nix /nix/var /nix/var/log /nix/var/log/nix /nix/var/log/nix/drvs /nix/var/nix{,/db,/gcroots,/profiles,/temproots,/userpool} /nix/var/nix/{gcroots,profiles}/per-user

    _sudo "to make the basic directory structure of Nix (part 2)" \
          install -dv -g "$NIX_BUILD_GROUP_NAME" -m 1775 /nix/store
@@ -38,7 +38,7 @@ fi

 # Determine if we could use the multi-user installer or not
 if [ "$(uname -s)" = "Linux" ]; then
-    echo "Note: a multi-user installation is possible. See https://nixos.org/manual/nix/stable/installation/installing-binary.html#multi-user-installation" >&2
+    echo "Note: a multi-user installation is possible. See https://nixos.org/nix/manual/#sect-multi-user-installation" >&2
 fi

 case "$(uname -s)" in
@@ -98,7 +98,7 @@ while [ $# -gt 0 ]; do
                echo "              providing multi-user support and better isolation for local builds."
                echo "              Both for security and reproducibility, this method is recommended if"
                echo "              supported on your platform."
-                echo "              See https://nixos.org/manual/nix/stable/installation/installing-binary.html#multi-user-installation"
+                echo "              See https://nixos.org/nix/manual/#sect-multi-user-installation"
                echo ""
                echo " --no-daemon: Simple, single-user installation that does not require root and is"
                echo "              trivial to uninstall."
@@ -144,7 +144,7 @@ if ! [ -e "$dest" ]; then
 fi

 if ! [ -w "$dest" ]; then
-    echo "$0: directory $dest exists, but is not writable by you. This could indicate that another user has already performed a single-user installation of Nix on this system. If you wish to enable multi-user support see https://nixos.org/manual/nix/stable/installation/multi-user.html. If you wish to continue with a single-user install for $USER please run 'chown -R $USER $dest' as root." >&2
+    echo "$0: directory $dest exists, but is not writable by you. This could indicate that another user has already performed a single-user installation of Nix on this system. If you wish to enable multi-user support see https://nixos.org/nix/manual/#ssec-multi-user. If you wish to continue with a single-user install for $USER please run 'chown -R $USER $dest' as root." >&2
    exit 1
 fi

@@ -0,0 +1,18 @@
+Copyright (c) 2014 Chase Geigle
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
@@ -54,36 +54,6 @@ void StoreCommand::run()
    run(getStore());
 }

-CopyCommand::CopyCommand()
-{
-    addFlag({
-        .longName = "from",
-        .description = "URL of the source Nix store.",
-        .labels = {"store-uri"},
-        .handler = {&srcUri},
-    });
-
-    addFlag({
-        .longName = "to",
-        .description = "URL of the destination Nix store.",
-        .labels = {"store-uri"},
-        .handler = {&dstUri},
-    });
-}
-
-ref<Store> CopyCommand::createStore()
-{
-    return srcUri.empty() ? StoreCommand::createStore() : openStore(srcUri);
-}
-
-ref<Store> CopyCommand::getDstStore()
-{
-    if (srcUri.empty() && dstUri.empty())
-        throw UsageError("you must pass '--from' and/or '--to'");
-
-    return dstUri.empty() ? openStore() : openStore(dstUri);
-}
-
 EvalCommand::EvalCommand()
 {
 }
@@ -104,15 +74,7 @@ ref<Store> EvalCommand::getEvalStore()
 ref<EvalState> EvalCommand::getEvalState()
 {
    if (!evalState)
-        evalState =
-            #if HAVE_BOEHMGC
-            std::allocate_shared<EvalState>(traceable_allocator<EvalState>(),
-                searchPath, getEvalStore(), getStore())
-            #else
-            std::make_shared<EvalState>(
-                searchPath, getEvalStore(), getStore())
-            #endif
-            ;
+        evalState = std::make_shared<EvalState>(searchPath, getEvalStore(), getStore());
    return ref<EvalState>(evalState);
 }

@@ -43,19 +43,6 @@ private:
    std::shared_ptr<Store> _store;
 };

-/* A command that copies something between `--from` and `--to`
-   stores. */
-struct CopyCommand : virtual StoreCommand
-{
-    std::string srcUri, dstUri;
-
-    CopyCommand();
-
-    ref<Store> createStore() override;
-
-    ref<Store> getDstStore();
-};
-
 struct EvalCommand : virtual StoreCommand, MixEvalArgs
 {
    EvalCommand();
@@ -191,7 +191,7 @@ void SourceExprCommand::completeInstallable(std::string_view prefix)
        auto sep = prefix_.rfind('.');
        std::string searchWord;
        if (sep != std::string::npos) {
-            searchWord = prefix_.substr(sep + 1, std::string::npos);
+            searchWord = prefix_.substr(sep, std::string::npos);
            prefix_ = prefix_.substr(0, sep);
        } else {
            searchWord = prefix_;
@@ -203,8 +203,6 @@ 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 = i.name;
@@ -234,9 +232,7 @@ void completeFlakeRefWithFragment(
       prefix. */
    try {
        auto hash = prefix.find('#');
-        if (hash == std::string::npos) {
-            completeFlakeRef(evalState->store, prefix);
-        } else {
+        if (hash != std::string::npos) {
            auto fragment = prefix.substr(hash + 1);
            auto flakeRefS = std::string(prefix.substr(0, hash));
            // FIXME: do tilde expansion.
@@ -252,8 +248,6 @@ void completeFlakeRefWithFragment(
               flake. */
            attrPathPrefixes.push_back("");

-            completionType = ctAttrs;
-
            for (auto & attrPathPrefixS : attrPathPrefixes) {
                auto attrPathPrefix = parseAttrPath(*evalState, attrPathPrefixS);
                auto attrPathS = attrPathPrefixS + std::string(fragment);
@@ -291,13 +285,12 @@ void completeFlakeRefWithFragment(
    } catch (Error & e) {
        warn(e.msg());
    }
+
+    completeFlakeRef(evalState->store, prefix);
 }

 void completeFlakeRef(ref<Store> store, std::string_view prefix)
 {
-    if (!settings.isExperimentalFeatureEnabled(Xp::Flakes))
-        return;
-
    if (prefix == "")
        completions->add(".");

@@ -345,18 +338,6 @@ Installable::getCursor(EvalState & state)
    return cursors[0];
 }

-static StorePath getDeriver(
-    ref<Store> store,
-    const Installable & i,
-    const StorePath & drvPath)
-{
-    auto derivers = store->queryValidDerivers(drvPath);
-    if (derivers.empty())
-        throw Error("'%s' does not have a known deriver", i.what());
-    // FIXME: use all derivers?
-    return *derivers.begin();
-}
-
 struct InstallableStorePath : Installable
 {
    ref<Store> store;
@@ -365,7 +346,7 @@ struct InstallableStorePath : Installable
    InstallableStorePath(ref<Store> store, StorePath && storePath)
        : store(store), storePath(std::move(storePath)) { }

-    std::string what() const override { return store->printStorePath(storePath); }
+    std::string what() override { return store->printStorePath(storePath); }

    DerivedPaths toDerivedPaths() override
    {
@@ -386,15 +367,6 @@ struct InstallableStorePath : Installable
        }
    }

-    StorePathSet toDrvPaths(ref<Store> store) override
-    {
-        if (storePath.isDerivation()) {
-            return {storePath};
-        } else {
-            return {getDeriver(store, *this, storePath)};
-        }
-    }
-
    std::optional<StorePath> getStorePath() override
    {
        return storePath;
@@ -423,14 +395,6 @@ DerivedPaths InstallableValue::toDerivedPaths()
    return res;
 }

-StorePathSet InstallableValue::toDrvPaths(ref<Store> store)
-{
-    StorePathSet res;
-    for (auto & drv : toDerivations())
-        res.insert(drv.drvPath);
-    return res;
-}
-
 struct InstallableAttrPath : InstallableValue
 {
    SourceExprCommand & cmd;
@@ -441,7 +405,7 @@ struct InstallableAttrPath : InstallableValue
        : InstallableValue(state), cmd(cmd), v(allocRootValue(v)), attrPath(attrPath)
    { }

-    std::string what() const override { return attrPath; }
+    std::string what() override { return attrPath; }

    std::pair<Value *, Pos> toValue(EvalState & state) override
    {
@@ -865,7 +829,11 @@ StorePathSet toDerivations(
                [&](const DerivedPath::Opaque & bo) {
                    if (!useDeriver)
                        throw Error("argument '%s' did not evaluate to a derivation", i->what());
-                    drvPaths.insert(getDeriver(store, *i, bo.path));
+                    auto derivers = store->queryValidDerivers(bo.path);
+                    if (derivers.empty())
+                        throw Error("'%s' does not have a known deriver", i->what());
+                    // FIXME: use all derivers?
+                    drvPaths.insert(*derivers.begin());
                },
                [&](const DerivedPath::Built & bfd) {
                    drvPaths.insert(bfd.drvPath);
@@ -33,15 +33,10 @@ struct Installable
 {
    virtual ~Installable() { }

-    virtual std::string what() const = 0;
+    virtual std::string what() = 0;

    virtual DerivedPaths toDerivedPaths() = 0;

-    virtual StorePathSet toDrvPaths(ref<Store> store)
-    {
-        throw Error("'%s' cannot be converted to a derivation path", what());
-    }
-
    DerivedPath toDerivedPath();

    UnresolvedApp toApp(EvalState & state);
@@ -86,8 +81,6 @@ struct InstallableValue : Installable
    virtual std::vector<DerivationInfo> toDerivations() = 0;

    DerivedPaths toDerivedPaths() override;
-
-    StorePathSet toDrvPaths(ref<Store> store) override;
 };

 struct InstallableFlake : InstallableValue
@@ -106,7 +99,7 @@ struct InstallableFlake : InstallableValue
        Strings && prefixes,
        const flake::LockFlags & lockFlags);

-    std::string what() const override { return flakeRef.to_string() + "#" + *attrPaths.begin(); }
+    std::string what() override { return flakeRef.to_string() + "#" + *attrPaths.begin(); }

    std::vector<std::string> getActualAttrPaths();

@@ -7,19 +7,26 @@
 namespace nix {


-
 /* Allocate a new array of attributes for an attribute set with a specific
   capacity. The space is implicitly reserved after the Bindings
   structure. */
 Bindings * EvalState::allocBindings(size_t capacity)
 {
-    if (capacity == 0)
-        return &emptyBindings;
    if (capacity > std::numeric_limits<Bindings::size_t>::max())
        throw Error("attribute set of size %d is too big", capacity);
+    return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings((Bindings::size_t) capacity);
+}
+
+
+void EvalState::mkAttrs(Value & v, size_t capacity)
+{
+    if (capacity == 0) {
+        v = vEmptySet;
+        return;
+    }
+    v.mkAttrs(allocBindings(capacity));
    nrAttrsets++;
    nrAttrsInAttrsets += capacity;
-    return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings((Bindings::size_t) capacity);
 }


@@ -34,36 +41,15 @@ Value * EvalState::allocAttr(Value & vAttrs, const Symbol & name)
 }


-Value * EvalState::allocAttr(Value & vAttrs, std::string_view name)
+Value * EvalState::allocAttr(Value & vAttrs, const std::string & name)
 {
    return allocAttr(vAttrs, symbols.create(name));
 }


-Value & BindingsBuilder::alloc(const Symbol & name, ptr<Pos> pos)
-{
-    auto value = state.allocValue();
-    bindings->push_back(Attr(name, value, pos));
-    return *value;
-}
-
-
-Value & BindingsBuilder::alloc(std::string_view name, ptr<Pos> pos)
-{
-    return alloc(state.symbols.create(name), pos);
-}
-
-
 void Bindings::sort()
 {
-    if (size_) std::sort(begin(), end());
-}
-
-
-Value & Value::mkAttrs(BindingsBuilder & bindings)
-{
-    mkAttrs(bindings.finish());
-    return *this;
+    std::sort(begin(), end());
 }


@@ -113,52 +113,5 @@ public:
    friend class EvalState;
 };

-/* A wrapper around Bindings that ensures that its always in sorted
-   order at the end. The only way to consume a BindingsBuilder is to
-   call finish(), which sorts the bindings. */
-class BindingsBuilder
-{
-    Bindings * bindings;
-
-public:
-    // needed by std::back_inserter
-    using value_type = Attr;
-
-    EvalState & state;
-
-    BindingsBuilder(EvalState & state, Bindings * bindings)
-        : bindings(bindings), state(state)
-    { }
-
-    void insert(Symbol name, Value * value, ptr<Pos> pos = ptr(&noPos))
-    {
-        insert(Attr(name, value, pos));
-    }
-
-    void insert(const Attr & attr)
-    {
-        push_back(attr);
-    }
-
-    void push_back(const Attr & attr)
-    {
-        bindings->push_back(attr);
-    }
-
-    Value & alloc(const Symbol & name, ptr<Pos> pos = ptr(&noPos));
-
-    Value & alloc(std::string_view name, ptr<Pos> pos = ptr(&noPos));
-
-    Bindings * finish()
-    {
-        bindings->sort();
-        return bindings;
-    }
-
-    Bindings * alreadySorted()
-    {
-        return bindings;
-    }
-};

 }
@@ -73,16 +73,17 @@ MixEvalArgs::MixEvalArgs()

 Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
 {
-    auto res = state.buildBindings(autoArgs.size());
+    Bindings * res = state.allocBindings(autoArgs.size());
    for (auto & i : autoArgs) {
-        auto v = state.allocValue();
+        Value * v = state.allocValue();
        if (i.second[0] == 'E')
            state.mkThunk_(*v, state.parseExprFromString(string(i.second, 1), absPath(".")));
        else
-            v->mkString(((std::string_view) i.second).substr(1));
-        res.insert(state.symbols.create(i.first), v);
+            mkString(*v, string(i.second, 1));
+        res->push_back(Attr(state.symbols.create(i.first), v));
    }
-    return res.finish();
+    res->sort();
+    return res;
 }

 Path lookupFileArg(EvalState & state, string s)
@@ -36,19 +36,6 @@
 namespace nix {


-static char * allocString(size_t size)
-{
-    char * t;
-#if HAVE_BOEHMGC
-    t = (char *) GC_MALLOC_ATOMIC(size);
-#else
-    t = malloc(size);
-#endif
-    if (!t) throw std::bad_alloc();
-    return t;
-}
-
-
 static char * dupString(const char * s)
 {
    char * t;
@@ -158,7 +145,7 @@ void printValue(std::ostream & str, std::set<const Value *> & active, const Valu
        str << v.fpoint;
        break;
    default:
-        abort();
+        throw Error("invalid value");
    }

    active.erase(&v);
@@ -425,21 +412,10 @@ EvalState::EvalState(
    , sDescription(symbols.create("description"))
    , sSelf(symbols.create("self"))
    , sEpsilon(symbols.create(""))
-    , sStartSet(symbols.create("startSet"))
-    , sOperator(symbols.create("operator"))
-    , sKey(symbols.create("key"))
-    , sPath(symbols.create("path"))
-    , sPrefix(symbols.create("prefix"))
    , repair(NoRepair)
-    , emptyBindings(0)
    , store(store)
    , buildStore(buildStore ? buildStore : store)
    , regexCache(makeRegexCache())
-#if HAVE_BOEHMGC
-    , valueAllocCache(std::allocate_shared<void *>(traceable_allocator<void *>(), nullptr))
-#else
-    , valueAllocCache(std::make_shared<void *>(nullptr))
-#endif
    , baseEnv(allocEnv(128))
    , staticBaseEnv(false, 0)
 {
@@ -478,6 +454,8 @@ EvalState::EvalState(
        }
    }

+    vEmptySet.mkAttrs(allocBindings(0));
+
    createBaseEnv();
 }

@@ -635,7 +613,7 @@ Value * EvalState::addPrimOp(const string & name,
        auto vPrimOp = allocValue();
        vPrimOp->mkPrimOp(new PrimOp { .fun = primOp, .arity = 1, .name = sym });
        Value v;
-        v.mkApp(vPrimOp, vPrimOp);
+        mkApp(v, *vPrimOp, *vPrimOp);
        return addConstant(name, v);
    }

@@ -657,7 +635,7 @@ Value * EvalState::addPrimOp(PrimOp && primOp)
        auto vPrimOp = allocValue();
        vPrimOp->mkPrimOp(new PrimOp(std::move(primOp)));
        Value v;
-        v.mkApp(vPrimOp, vPrimOp);
+        mkApp(v, *vPrimOp, *vPrimOp);
        return addConstant(primOp.name, v);
    }

@@ -788,14 +766,15 @@ LocalNoInline(void addErrorTrace(Error & e, const Pos & pos, const char * s, con
 }


-void Value::mkString(std::string_view s)
+void mkString(Value & v, const char * s)
 {
-    mkString(dupStringWithLen(s.data(), s.size()));
+    v.mkString(dupString(s));
 }


-static void copyContextToValue(Value & v, const PathSet & context)
+Value & mkString(Value & v, std::string_view s, const PathSet & context)
 {
+    v.mkString(dupStringWithLen(s.data(), s.size()));
    if (!context.empty()) {
        size_t n = 0;
        v.string.context = (const char * *)
@@ -804,24 +783,13 @@ static void copyContextToValue(Value & v, const PathSet & context)
            v.string.context[n++] = dupString(i.c_str());
        v.string.context[n] = 0;
    }
-}
-
-void Value::mkString(std::string_view s, const PathSet & context)
-{
-    mkString(s);
-    copyContextToValue(*this, context);
-}
-
-void Value::mkStringMove(const char * s, const PathSet & context)
-{
-    mkString(s);
-    copyContextToValue(*this, context);
+    return v;
 }


-void Value::mkPath(std::string_view s)
+void mkPath(Value & v, const char * s)
 {
-    mkPath(dupStringWithLen(s.data(), s.size()));
+    v.mkPath(dupString(s));
 }


@@ -853,23 +821,8 @@ inline Value * EvalState::lookupVar(Env * env, const ExprVar & var, bool noEval)

 Value * EvalState::allocValue()
 {
-    /* 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;
-    GC_PTR_STORE_AND_DIRTY(&*valueAllocCache, GC_NEXT(p));
-    GC_NEXT(p) = nullptr;
-
    nrValues++;
-    auto v = (Value *) p;
+    auto v = (Value *) allocBytes(sizeof(Value));
    return v;
 }

@@ -914,13 +867,13 @@ void EvalState::mkThunk_(Value & v, Expr * expr)
 void EvalState::mkPos(Value & v, ptr<Pos> pos)
 {
    if (pos->file.set()) {
-        auto attrs = buildBindings(3);
-        attrs.alloc(sFile).mkString(pos->file);
-        attrs.alloc(sLine).mkInt(pos->line);
-        attrs.alloc(sColumn).mkInt(pos->column);
-        v.mkAttrs(attrs);
+        mkAttrs(v, 3);
+        mkString(*allocAttr(v, sFile), pos->file);
+        mkInt(*allocAttr(v, sLine), pos->line);
+        mkInt(*allocAttr(v, sColumn), pos->column);
+        v.attrs->sort();
    } else
-        v.mkNull();
+        mkNull(v);
 }


@@ -1099,8 +1052,8 @@ void ExprPath::eval(EvalState & state, Env & env, Value & v)

 void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
 {
-    v.mkAttrs(state.buildBindings(attrs.size() + dynamicAttrs.size()).finish());
-    auto dynamicEnv = &env;
+    state.mkAttrs(v, attrs.size() + dynamicAttrs.size());
+    Env *dynamicEnv = &env;

    if (recursive) {
        /* Create a new environment that contains the attributes in
@@ -1291,14 +1244,14 @@ void ExprOpHasAttr::eval(EvalState & state, Env & env, Value & v)
        if (vAttrs->type() != nAttrs ||
            (j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
        {
-            v.mkBool(false);
+            mkBool(v, false);
            return;
        } else {
            vAttrs = j->value;
        }
    }

-    v.mkBool(true);
+    mkBool(v, true);
 }


@@ -1373,7 +1326,7 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
                    /* Nope, so show the first unexpected argument to the
                       user. */
                    for (auto & i : *args[0]->attrs)
-                        if (!lambda.formals->argNames.count(i.name))
+                        if (lambda.formals->argNames.find(i.name) == lambda.formals->argNames.end())
                            throwTypeError(pos, "%1% called with unexpected argument '%2%'", lambda, i.name);
                    abort(); // can't happen
                }
@@ -1516,20 +1469,22 @@ void EvalState::autoCallFunction(Bindings & args, Value & fun, Value & res)
        return;
    }

-    auto attrs = buildBindings(std::max(static_cast<uint32_t>(fun.lambda.fun->formals->formals.size()), args.size()));
+    Value * actualArgs = allocValue();
+    mkAttrs(*actualArgs, std::max(static_cast<uint32_t>(fun.lambda.fun->formals->formals.size()), args.size()));

    if (fun.lambda.fun->formals->ellipsis) {
        // If the formals have an ellipsis (eg the function accepts extra args) pass
        // all available automatic arguments (which includes arguments specified on
        // the command line via --arg/--argstr)
-        for (auto & v : args)
-            attrs.insert(v);
+        for (auto& v : args) {
+            actualArgs->attrs->push_back(v);
+        }
    } else {
        // Otherwise, only pass the arguments that the function accepts
        for (auto & i : fun.lambda.fun->formals->formals) {
            Bindings::iterator j = args.find(i.name);
            if (j != args.end()) {
-                attrs.insert(*j);
+                actualArgs->attrs->push_back(*j);
            } else if (!i.def) {
                throwMissingArgumentError(i.pos, R"(cannot evaluate a function that has an argument without a value ('%1%')

@@ -1542,7 +1497,9 @@ https://nixos.org/manual/nix/stable/#ss-functions.)", i.name);
        }
    }

-    callFunction(fun, allocValue()->mkAttrs(attrs), res, noPos);
+    actualArgs->attrs->sort();
+
+    callFunction(fun, *actualArgs, res, noPos);
 }


@@ -1577,7 +1534,7 @@ void ExprAssert::eval(EvalState & state, Env & env, Value & v)

 void ExprOpNot::eval(EvalState & state, Env & env, Value & v)
 {
-    v.mkBool(!state.evalBool(env, e));
+    mkBool(v, !state.evalBool(env, e));
 }


@@ -1585,7 +1542,7 @@ void ExprOpEq::eval(EvalState & state, Env & env, Value & v)
 {
    Value v1; e1->eval(state, env, v1);
    Value v2; e2->eval(state, env, v2);
-    v.mkBool(state.eqValues(v1, v2));
+    mkBool(v, state.eqValues(v1, v2));
 }


@@ -1593,25 +1550,25 @@ void ExprOpNEq::eval(EvalState & state, Env & env, Value & v)
 {
    Value v1; e1->eval(state, env, v1);
    Value v2; e2->eval(state, env, v2);
-    v.mkBool(!state.eqValues(v1, v2));
+    mkBool(v, !state.eqValues(v1, v2));
 }


 void ExprOpAnd::eval(EvalState & state, Env & env, Value & v)
 {
-    v.mkBool(state.evalBool(env, e1, pos) && state.evalBool(env, e2, pos));
+    mkBool(v, state.evalBool(env, e1, pos) && state.evalBool(env, e2, pos));
 }


 void ExprOpOr::eval(EvalState & state, Env & env, Value & v)
 {
-    v.mkBool(state.evalBool(env, e1, pos) || state.evalBool(env, e2, pos));
+    mkBool(v, state.evalBool(env, e1, pos) || state.evalBool(env, e2, pos));
 }


 void ExprOpImpl::eval(EvalState & state, Env & env, Value & v)
 {
-    v.mkBool(!state.evalBool(env, e1, pos) || state.evalBool(env, e2, pos));
+    mkBool(v, !state.evalBool(env, e1, pos) || state.evalBool(env, e2, pos));
 }


@@ -1626,7 +1583,7 @@ void ExprOpUpdate::eval(EvalState & state, Env & env, Value & v)
    if (v1.attrs->size() == 0) { v = v2; return; }
    if (v2.attrs->size() == 0) { v = v1; return; }

-    auto attrs = state.buildBindings(v1.attrs->size() + v2.attrs->size());
+    state.mkAttrs(v, v1.attrs->size() + v2.attrs->size());

    /* Merge the sets, preferring values from the second set.  Make
       sure to keep the resulting vector in sorted order. */
@@ -1635,19 +1592,17 @@ void ExprOpUpdate::eval(EvalState & state, Env & env, Value & v)

    while (i != v1.attrs->end() && j != v2.attrs->end()) {
        if (i->name == j->name) {
-            attrs.insert(*j);
+            v.attrs->push_back(*j);
            ++i; ++j;
        }
        else if (i->name < j->name)
-            attrs.insert(*i++);
+            v.attrs->push_back(*i++);
        else
-            attrs.insert(*j++);
+            v.attrs->push_back(*j++);
    }

-    while (i != v1.attrs->end()) attrs.insert(*i++);
-    while (j != v2.attrs->end()) attrs.insert(*j++);
-
-    v.mkAttrs(attrs.alreadySorted());
+    while (i != v1.attrs->end()) v.attrs->push_back(*i++);
+    while (j != v2.attrs->end()) v.attrs->push_back(*j++);

    state.nrOpUpdateValuesCopied += v.attrs->size();
 }
@@ -1694,35 +1649,14 @@ void EvalState::concatLists(Value & v, size_t nrLists, Value * * lists, const Po
 void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
 {
    PathSet context;
-    std::vector<std::string> s;
-    size_t sSize = 0;
+    std::ostringstream s;
    NixInt n = 0;
    NixFloat nf = 0;

    bool first = !forceString;
    ValueType firstType = nString;

-    const auto str = [&] {
-        std::string result;
-        result.reserve(sSize);
-        for (const auto & part : s) result += part;
-        return result;
-    };
-    /* c_str() is not str().c_str() because we want to create a string
-       Value. allocating a GC'd string directly and moving it into a
-       Value lets us avoid an allocation and copy. */
-    const auto c_str = [&] {
-        char * result = allocString(sSize + 1);
-        char * tmp = result;
-        for (const auto & part : s) {
-            memcpy(tmp, part.c_str(), part.size());
-            tmp += part.size();
-        }
-        *tmp = 0;
-        return result;
-    };
-
-    for (auto & [i_pos, i] : *es) {
+    for (auto & i : *es) {
        Value vTmp;
        i->eval(state, env, vTmp);

@@ -1743,37 +1677,34 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
                nf = n;
                nf += vTmp.fpoint;
            } else
-                throwEvalError(i_pos, "cannot add %1% to an integer", showType(vTmp));
+                throwEvalError(pos, "cannot add %1% to an integer", showType(vTmp));
        } else if (firstType == nFloat) {
            if (vTmp.type() == nInt) {
                nf += vTmp.integer;
            } else if (vTmp.type() == nFloat) {
                nf += vTmp.fpoint;
            } else
-                throwEvalError(i_pos, "cannot add %1% to a float", showType(vTmp));
-        } else {
-            if (s.empty()) s.reserve(es->size());
+                throwEvalError(pos, "cannot add %1% to a float", showType(vTmp));
+        } else
            /* skip canonization of first path, which would only be not
            canonized in the first place if it's coming from a ./${foo} type
            path */
-            s.emplace_back(
-                state.coerceToString(i_pos, vTmp, context, false, firstType == nString, !first));
-            sSize += s.back().size();
-        }
+            s << state.coerceToString(pos, vTmp, context, false, firstType == nString, !first);

        first = false;
    }

    if (firstType == nInt)
-        v.mkInt(n);
+        mkInt(v, n);
    else if (firstType == nFloat)
-        v.mkFloat(nf);
+        mkFloat(v, nf);
    else if (firstType == nPath) {
        if (!context.empty())
            throwEvalError(pos, "a string that refers to a store path cannot be appended to a path");
-        v.mkPath(canonPath(str()));
+        auto path = canonPath(s.str());
+        mkPath(v, path.c_str());
    } else
-        v.mkStringMove(c_str(), context);
+        mkString(v, s.str(), context);
 }


@@ -44,6 +44,8 @@ struct Env
 };


+Value & mkString(Value & v, std::string_view s, const PathSet & context = PathSet());
+
 void copyContext(const Value & v, PathSet & context);


@@ -80,8 +82,7 @@ public:
        sContentAddressed,
        sOutputHash, sOutputHashAlgo, sOutputHashMode,
        sRecurseForDerivations,
-        sDescription, sSelf, sEpsilon, sStartSet, sOperator, sKey, sPath,
-        sPrefix;
+        sDescription, sSelf, sEpsilon;
    Symbol sDerivationNix;

    /* If set, force copying files to the Nix store even if they
@@ -92,7 +93,7 @@ public:
       mode. */
    std::optional<PathSet> allowedPaths;

-    Bindings emptyBindings;
+    Value vEmptySet;

    /* Store used to materialise .drv files. */
    const ref<Store> store;
@@ -132,9 +133,6 @@ private:
    /* Cache used by prim_match(). */
    std::shared_ptr<RegexCache> regexCache;

-    /* Allocation cache for GC'd Value objects. */
-    std::shared_ptr<void *> valueAllocCache;
-
 public:

    EvalState(
@@ -180,8 +178,8 @@ public:
    Expr * parseExprFromFile(const Path & path, StaticEnv & staticEnv);

    /* Parse a Nix expression from the specified string. */
-    Expr * parseExprFromString(std::string s, const Path & basePath, StaticEnv & staticEnv);
-    Expr * parseExprFromString(std::string s, const Path & basePath);
+    Expr * parseExprFromString(std::string_view s, const Path & basePath, StaticEnv & staticEnv);
+    Expr * parseExprFromString(std::string_view s, const Path & basePath);

    Expr * parseStdin();

@@ -309,7 +307,7 @@ private:
    friend struct ExprAttrs;
    friend struct ExprLet;

-    Expr * parse(char * text, size_t length, FileOrigin origin, const Path & path,
+    Expr * parse(const char * text, FileOrigin origin, const Path & path,
        const Path & basePath, StaticEnv & staticEnv);

 public:
@@ -338,16 +336,12 @@ public:
    Env & allocEnv(size_t size);

    Value * allocAttr(Value & vAttrs, const Symbol & name);
-    Value * allocAttr(Value & vAttrs, std::string_view name);
+    Value * allocAttr(Value & vAttrs, const std::string & name);

    Bindings * allocBindings(size_t capacity);

-    BindingsBuilder buildBindings(size_t capacity)
-    {
-        return BindingsBuilder(*this, allocBindings(capacity));
-    }
-
    void mkList(Value & v, size_t length);
+    void mkAttrs(Value & v, size_t capacity);
    void mkThunk_(Value & v, Expr * expr);
    void mkPos(Value & v, ptr<Pos> pos);

@@ -356,10 +350,7 @@ public:
    /* Print statistics. */
    void printStats();

-    /* Realise the given context, and return a mapping from the placeholders
-     * used to construct the associated value to their final store path
-     */
-    [[nodiscard]] StringMap realiseContext(const PathSet & context);
+    void realiseContext(const PathSet & context);

 private:

@@ -400,9 +391,6 @@ private:
    friend struct ExprSelect;
    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;
 };


@@ -38,11 +38,11 @@ void ConfigFile::apply()

        // FIXME: Move into libutil/config.cc.
        std::string valueS;
-        if (auto* s = std::get_if<std::string>(&value))
+        if (auto s = std::get_if<std::string>(&value))
            valueS = *s;
-        else if (auto* n = std::get_if<int64_t>(&value))
-            valueS = fmt("%d", *n);
-        else if (auto* b = std::get_if<Explicit<bool>>(&value))
+        else if (auto n = std::get_if<int64_t>(&value))
+            valueS = fmt("%d", n);
+        else if (auto b = std::get_if<Explicit<bool>>(&value))
            valueS = b->t ? "true" : "false";
        else if (auto ss = std::get_if<std::vector<std::string>>(&value))
            valueS = concatStringsSep(" ", *ss); // FIXME: evil
@@ -155,7 +155,7 @@ static FlakeInput parseFlakeInput(EvalState & state,
        if (!attrs.empty())
            throw Error("unexpected flake input attribute '%s', at %s", attrs.begin()->first, pos);
        if (url)
-            input.ref = parseFlakeRef(*url, baseDir, true, input.isFlake);
+            input.ref = parseFlakeRef(*url, baseDir, true);
    }

    if (!input.follows && !input.ref)
@@ -194,8 +194,8 @@ static Flake getFlake(
        state, originalRef, allowLookup, flakeCache);

    // Guard against symlink attacks.
-    auto flakeDir = canonPath(sourceInfo.actualPath + "/" + lockedRef.subdir, true);
-    auto flakeFile = canonPath(flakeDir + "/flake.nix", true);
+    auto flakeDir = canonPath(sourceInfo.actualPath + "/" + lockedRef.subdir);
+    auto flakeFile = canonPath(flakeDir + "/flake.nix");
    if (!isInDir(flakeFile, sourceInfo.actualPath))
        throw Error("'flake.nix' file of flake '%s' escapes from '%s'",
            lockedRef, state.store->printStorePath(sourceInfo.storePath));
@@ -251,14 +251,10 @@ static Flake getFlake(
            forceTrivialValue(state, *setting.value, *setting.pos);
            if (setting.value->type() == nString)
                flake.config.settings.insert({setting.name, state.forceStringNoCtx(*setting.value, *setting.pos)});
-            else if (setting.value->type() == nPath) {
-                PathSet emptyContext = {};
-                flake.config.settings.insert({setting.name, state.coerceToString(*setting.pos, *setting.value, emptyContext, false, true, true)});
-            }
            else if (setting.value->type() == nInt)
                flake.config.settings.insert({setting.name, state.forceInt(*setting.value, *setting.pos)});
            else if (setting.value->type() == nBool)
-                flake.config.settings.insert({setting.name, Explicit<bool> { state.forceBool(*setting.value, *setting.pos) }});
+                flake.config.settings.insert({setting.name, state.forceBool(*setting.value, *setting.pos)});
            else if (setting.value->type() == nList) {
                std::vector<std::string> ss;
                for (auto elem : setting.value->listItems()) {
@@ -348,8 +344,7 @@ LockedFlake lockFlake(
            const InputPath & inputPathPrefix,
            std::shared_ptr<const Node> oldNode,
            const LockParent & parent,
-            const Path & parentPath,
-            bool trustLock)>
+            const Path & parentPath)>
            computeLocks;

        computeLocks = [&](
@@ -358,8 +353,7 @@ LockedFlake lockFlake(
            const InputPath & inputPathPrefix,
            std::shared_ptr<const Node> oldNode,
            const LockParent & parent,
-            const Path & parentPath,
-            bool trustLock)
+            const Path & parentPath)
        {
            debug("computing lock file node '%s'", printInputPath(inputPathPrefix));

@@ -470,20 +464,14 @@ LockedFlake lockFlake(
                                        .isFlake = (*lockedNode)->isFlake,
                                    });
                                } else if (auto follows = std::get_if<1>(&i.second)) {
-                                    if (! trustLock) {
-                                        // It is possible that the flake has changed,
-                                        // so we must confirm all the follows that are in the lockfile are also in the flake.
-                                        auto overridePath(inputPath);
-                                        overridePath.push_back(i.first);
-                                        auto o = overrides.find(overridePath);
-                                        // If the override disappeared, we have to refetch the flake,
-                                        // since some of the inputs may not be present in the lockfile.
-                                        if (o == overrides.end()) {
-                                            mustRefetch = true;
-                                            // There's no point populating the rest of the fake inputs,
-                                            // since we'll refetch the flake anyways.
-                                            break;
-                                        }
+                                    auto o = input.overrides.find(i.first);
+                                    // If the override disappeared, we have to refetch the flake,
+                                    // since some of the inputs may not be present in the lockfile.
+                                    if (o == input.overrides.end()) {
+                                        mustRefetch = true;
+                                        // There's no point populating the rest of the fake inputs,
+                                        // since we'll refetch the flake anyways.
+                                        break;
                                    }
                                    fakeInputs.emplace(i.first, FlakeInput {
                                        .follows = *follows,
@@ -492,16 +480,11 @@ LockedFlake lockFlake(
                            }
                        }

-                        LockParent newParent {
-                            .path = inputPath,
-                            .absolute = true
-                        };
-
                        computeLocks(
                            mustRefetch
                            ? getFlake(state, oldLock->lockedRef, false, flakeCache).inputs
                            : fakeInputs,
-                            childNode, inputPath, oldLock, newParent, parentPath, !mustRefetch);
+                            childNode, inputPath, oldLock, parent, parentPath);

                    } else {
                        /* We need to create a new lock file entry. So fetch
@@ -558,7 +541,7 @@ LockedFlake lockFlake(
                                ? std::dynamic_pointer_cast<const Node>(oldLock)
                                : LockFile::read(
                                    inputFlake.sourceInfo->actualPath + "/" + inputFlake.lockedRef.subdir + "/flake.lock").root,
-                                newParent, localPath, false);
+                                newParent, localPath);
                        }

                        else {
@@ -582,11 +565,11 @@ LockedFlake lockFlake(
        };

        // Bring in the current ref for relative path resolution if we have it
-        auto parentPath = canonPath(flake.sourceInfo->actualPath + "/" + flake.lockedRef.subdir, true);
+        auto parentPath = canonPath(flake.sourceInfo->actualPath + "/" + flake.lockedRef.subdir);

        computeLocks(
            flake.inputs, newLockFile.root, {},
-            lockFlags.recreateLockFile ? nullptr : oldLockFile.root, parent, parentPath, false);
+            lockFlags.recreateLockFile ? nullptr : oldLockFile.root, parent, parentPath);

        for (auto & i : lockFlags.inputOverrides)
            if (!overridesUsed.count(i.first))
@@ -633,24 +616,12 @@ LockedFlake lockFlake(

                        newLockFile.write(path);

-                        std::optional<std::string> commitMessage = std::nullopt;
-                        if (lockFlags.commitLockFile) {
-                            std::string cm;
-
-                            cm = settings.commitLockFileSummary.get();
-
-                            if (cm == "") {
-                                cm = fmt("%s: %s", relPath, lockFileExists ? "Update" : "Add");
-                            }
-
-                            cm += "\n\nFlake lock file updates:\n\n";
-                            cm += filterANSIEscapes(diff, true);
-                            commitMessage = cm;
-                        }
-
                        topRef.input.markChangedFile(
                            (topRef.subdir == "" ? "" : topRef.subdir + "/") + "flake.lock",
-                            commitMessage);
+                            lockFlags.commitLockFile
+                            ? std::optional<std::string>(fmt("%s: %s\n\nFlake lock file changes:\n\n%s",
+                                    relPath, lockFileExists ? "Update" : "Add", filterANSIEscapes(diff, true)))
+                            : std::nullopt);

                        /* Rewriting the lockfile changed the top-level
                           repo, so we should re-read it. FIXME: we could
@@ -698,7 +669,7 @@ void callFlake(EvalState & state,
    auto vTmp1 = state.allocValue();
    auto vTmp2 = state.allocValue();

-    vLocks->mkString(lockedFlake.lockFile.to_string());
+    mkString(*vLocks, lockedFlake.lockFile.to_string());

    emitTreeAttrs(
        state,
@@ -708,7 +679,7 @@ void callFlake(EvalState & state,
        false,
        lockedFlake.flake.forceDirty);

-    vRootSubdir->mkString(lockedFlake.flake.lockedRef.subdir);
+    mkString(*vRootSubdir, lockedFlake.flake.lockedRef.subdir);

    if (!state.vCallFlake) {
        state.vCallFlake = allocRootValue(state.allocValue());
@@ -48,12 +48,9 @@ FlakeRef FlakeRef::resolve(ref<Store> store) const
 }

 FlakeRef parseFlakeRef(
-    const std::string & url,
-    const std::optional<Path> & baseDir,
-    bool allowMissing,
-    bool isFlake)
+    const std::string & url, const std::optional<Path> & baseDir, bool allowMissing)
 {
-    auto [flakeRef, fragment] = parseFlakeRefWithFragment(url, baseDir, allowMissing, isFlake);
+    auto [flakeRef, fragment] = parseFlakeRefWithFragment(url, baseDir, allowMissing);
    if (fragment != "")
        throw Error("unexpected fragment '%s' in flake reference '%s'", fragment, url);
    return flakeRef;
@@ -70,10 +67,7 @@ std::optional<FlakeRef> maybeParseFlakeRef(
 }

 std::pair<FlakeRef, std::string> parseFlakeRefWithFragment(
-    const std::string & url,
-    const std::optional<Path> & baseDir,
-    bool allowMissing,
-    bool isFlake)
+    const std::string & url, const std::optional<Path> & baseDir, bool allowMissing)
 {
    using namespace fetchers;

@@ -118,71 +112,46 @@ std::pair<FlakeRef, std::string> parseFlakeRefWithFragment(
               to 'baseDir'). If so, search upward to the root of the
               repo (i.e. the directory containing .git). */

-            path = absPath(path, baseDir);
+            path = absPath(path, baseDir, true);

-            if (isFlake) {
+            if (!S_ISDIR(lstat(path).st_mode))
+                throw BadURL("path '%s' is not a flake (because it's not a directory)", path);

-                if (!allowMissing && !pathExists(path + "/flake.nix")){
-                    notice("path '%s' does not contain a 'flake.nix', searching up",path);
+            if (!allowMissing && !pathExists(path + "/flake.nix"))
+                throw BadURL("path '%s' is not a flake (because it doesn't contain a 'flake.nix' file)", path);

-                    // Save device to detect filesystem boundary
-                    dev_t device = lstat(path).st_dev;
-                    bool found = false;
-                    while (path != "/") {
-                        if (pathExists(path + "/flake.nix")) {
-                            found = true;
-                            break;
-                        } else if (pathExists(path + "/.git"))
-                            throw Error("path '%s' is not part of a flake (neither it nor its parent directories contain a 'flake.nix' file)", path);
-                        else {
-                            if (lstat(path).st_dev != device)
-                                throw Error("unable to find a flake before encountering filesystem boundary at '%s'", path);
-                        }
-                        path = dirOf(path);
-                    }
-                    if (!found)
-                        throw BadURL("could not find a flake.nix file");
-                }
+            auto flakeRoot = path;
+            std::string subdir;

-                if (!S_ISDIR(lstat(path).st_mode))
-                    throw BadURL("path '%s' is not a flake (because it's not a directory)", path);
+            while (flakeRoot != "/") {
+                if (pathExists(flakeRoot + "/.git")) {
+                    auto base = std::string("git+file://") + flakeRoot;

-                if (!allowMissing && !pathExists(path + "/flake.nix"))
-                    throw BadURL("path '%s' is not a flake (because it doesn't contain a 'flake.nix' file)", path);
+                    auto parsedURL = ParsedURL{
+                        .url = base, // FIXME
+                        .base = base,
+                        .scheme = "git+file",
+                        .authority = "",
+                        .path = flakeRoot,
+                        .query = decodeQuery(match[2]),
+                    };

-                auto flakeRoot = path;
-                std::string subdir;
-
-                while (flakeRoot != "/") {
-                    if (pathExists(flakeRoot + "/.git")) {
-                        auto base = std::string("git+file://") + flakeRoot;
-
-                        auto parsedURL = ParsedURL{
-                            .url = base, // FIXME
-                            .base = base,
-                            .scheme = "git+file",
-                            .authority = "",
-                            .path = flakeRoot,
-                            .query = decodeQuery(match[2]),
-                        };
-
-                        if (subdir != "") {
-                            if (parsedURL.query.count("dir"))
-                                throw Error("flake URL '%s' has an inconsistent 'dir' parameter", url);
-                            parsedURL.query.insert_or_assign("dir", subdir);
-                        }
-
-                        if (pathExists(flakeRoot + "/.git/shallow"))
-                            parsedURL.query.insert_or_assign("shallow", "1");
-
-                        return std::make_pair(
-                            FlakeRef(Input::fromURL(parsedURL), get(parsedURL.query, "dir").value_or("")),
-                            fragment);
+                    if (subdir != "") {
+                        if (parsedURL.query.count("dir"))
+                            throw Error("flake URL '%s' has an inconsistent 'dir' parameter", url);
+                        parsedURL.query.insert_or_assign("dir", subdir);
                    }

-                    subdir = std::string(baseNameOf(flakeRoot)) + (subdir.empty() ? "" : "/" + subdir);
-                    flakeRoot = dirOf(flakeRoot);
+                    if (pathExists(flakeRoot + "/.git/shallow"))
+                        parsedURL.query.insert_or_assign("shallow", "1");
+
+                    return std::make_pair(
+                        FlakeRef(Input::fromURL(parsedURL), get(parsedURL.query, "dir").value_or("")),
+                        fragment);
                }
+
+                subdir = std::string(baseNameOf(flakeRoot)) + (subdir.empty() ? "" : "/" + subdir);
+                flakeRoot = dirOf(flakeRoot);
            }

        } else {
@@ -62,19 +62,13 @@ struct FlakeRef
 std::ostream & operator << (std::ostream & str, const FlakeRef & flakeRef);

 FlakeRef parseFlakeRef(
-    const std::string & url,
-    const std::optional<Path> & baseDir = {},
-    bool allowMissing = false,
-    bool isFlake = true);
+    const std::string & url, const std::optional<Path> & baseDir = {}, bool allowMissing = false);

 std::optional<FlakeRef> maybeParseFlake(
    const std::string & url, const std::optional<Path> & baseDir = {});

 std::pair<FlakeRef, std::string> parseFlakeRefWithFragment(
-    const std::string & url,
-    const std::optional<Path> & baseDir = {},
-    bool allowMissing = false,
-    bool isFlake = true);
+    const std::string & url, const std::optional<Path> & baseDir = {}, bool allowMissing = false);

 std::optional<std::pair<FlakeRef, std::string>> maybeParseFlakeRefWithFragment(
    const std::string & url, const std::optional<Path> & baseDir = {});
@@ -254,14 +254,15 @@ bool DrvInfo::queryMetaBool(const string & name, bool def)
 void DrvInfo::setMeta(const string & name, Value * v)
 {
    getMeta();
-    auto attrs = state->buildBindings(1 + (meta ? meta->size() : 0));
+    Bindings * old = meta;
+    meta = state->allocBindings(1 + (old ? old->size() : 0));
    Symbol sym = state->symbols.create(name);
-    if (meta)
-        for (auto i : *meta)
+    if (old)
+        for (auto i : *old)
            if (i.name != sym)
-                attrs.insert(i);
-    if (v) attrs.insert(sym, v);
-    meta = attrs.finish();
+                meta->push_back(i);
+    if (v) meta->push_back(Attr(sym, v));
+    meta->sort();
 }


@@ -37,10 +37,10 @@ class JSONSax : nlohmann::json_sax<json> {
        ValueMap attrs;
        std::unique_ptr<JSONState> resolve(EvalState & state) override
        {
-            auto attrs2 = state.buildBindings(attrs.size());
+            Value & v = parent->value(state);
+            state.mkAttrs(v, attrs.size());
            for (auto & i : attrs)
-                attrs2.insert(i.first, i.second);
-            parent->value(state).mkAttrs(attrs2.alreadySorted());
+                v.attrs->push_back(Attr(i.first, i.second));
            return std::move(parent);
        }
        void add() override { v = nullptr; }
@@ -76,51 +76,45 @@ class JSONSax : nlohmann::json_sax<json> {
    EvalState & state;
    std::unique_ptr<JSONState> rs;

+    template<typename T, typename... Args> inline bool handle_value(T f, Args... args)
+    {
+        f(rs->value(state), args...);
+        rs->add();
+        return true;
+    }
+
 public:
    JSONSax(EvalState & state, Value & v) : state(state), rs(new JSONState(&v)) {};

    bool null()
    {
-        rs->value(state).mkNull();
-        rs->add();
-        return true;
+        return handle_value(mkNull);
    }

    bool boolean(bool val)
    {
-        rs->value(state).mkBool(val);
-        rs->add();
-        return true;
+        return handle_value(mkBool, val);
    }

    bool number_integer(number_integer_t val)
    {
-        rs->value(state).mkInt(val);
-        rs->add();
-        return true;
+        return handle_value(mkInt, val);
    }

    bool number_unsigned(number_unsigned_t val)
    {
-        rs->value(state).mkInt(val);
-        rs->add();
-        return true;
+        return handle_value(mkInt, val);
    }

    bool number_float(number_float_t val, const string_t & s)
    {
-        rs->value(state).mkFloat(val);
-        rs->add();
-        return true;
+        return handle_value(mkFloat, val);
    }

    bool string(string_t & val)
    {
-        rs->value(state).mkString(val);
-        rs->add();
-        return true;
+        return handle_value<void(Value&, const char*)>(mkString, val.c_str());
    }
-
 #if NLOHMANN_JSON_VERSION_MAJOR >= 3 && NLOHMANN_JSON_VERSION_MINOR >= 8
    bool binary(binary_t&)
    {
@@ -64,32 +64,29 @@ static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
 }


-// we make use of the fact that the parser receives a private copy of the input
-// string and can munge around in it.
-static Expr * unescapeStr(SymbolTable & symbols, char * s, size_t length)
+// FIXME: optimize
+static Expr * unescapeStr(SymbolTable & symbols, const char * s, size_t length)
 {
-    char * result = s;
-    char * t = s;
+    string t;
+    t.reserve(length);
    char c;
-    // the input string is terminated with *two* NULs, so we can safely take
-    // *one* character after the one being checked against.
    while ((c = *s++)) {
        if (c == '\\') {
+            assert(*s);
            c = *s++;
-            if (c == 'n') *t = '\n';
-            else if (c == 'r') *t = '\r';
-            else if (c == 't') *t = '\t';
-            else *t = c;
+            if (c == 'n') t += '\n';
+            else if (c == 'r') t += '\r';
+            else if (c == 't') t += '\t';
+            else t += c;
        }
        else if (c == '\r') {
            /* Normalise CR and CR/LF into LF. */
-            *t = '\n';
+            t += '\n';
            if (*s == '\n') s++; /* cr/lf */
        }
-        else *t = c;
-        t++;
+        else t += c;
    }
-    return new ExprString(symbols.create({result, size_t(t - result)}));
+    return new ExprString(symbols.create(t));
 }


@@ -142,7 +139,7 @@ or          { return OR_KW; }
 \/\/        { return UPDATE; }
 \+\+        { return CONCAT; }

-{ID}        { yylval->id = {yytext, (size_t) yyleng}; return ID; }
+{ID}        { yylval->id = strdup(yytext); return ID; }
 {INT}       { errno = 0;
              try {
                  yylval->n = boost::lexical_cast<int64_t>(yytext);
@@ -224,14 +221,14 @@ or          { return OR_KW; }
 <PATH_START>{PATH_SEG} {
  POP_STATE();
  PUSH_STATE(INPATH_SLASH);
-  yylval->path = {yytext, (size_t) yyleng};
+  yylval->path = strdup(yytext);
  return PATH;
 }

 <PATH_START>{HPATH_START} {
  POP_STATE();
  PUSH_STATE(INPATH_SLASH);
-  yylval->path = {yytext, (size_t) yyleng};
+  yylval->path = strdup(yytext);
  return HPATH;
 }

@@ -240,7 +237,7 @@ or          { return OR_KW; }
    PUSH_STATE(INPATH_SLASH);
  else
    PUSH_STATE(INPATH);
-  yylval->path = {yytext, (size_t) yyleng};
+  yylval->path = strdup(yytext);
  return PATH;
 }
 {HPATH} {
@@ -248,7 +245,7 @@ or          { return OR_KW; }
    PUSH_STATE(INPATH_SLASH);
  else
    PUSH_STATE(INPATH);
-  yylval->path = {yytext, (size_t) yyleng};
+  yylval->path = strdup(yytext);
  return HPATH;
 }

@@ -283,8 +280,8 @@ or          { return OR_KW; }
  throw ParseError("path has a trailing slash");
 }

-{SPATH}     { yylval->path = {yytext, (size_t) yyleng}; return SPATH; }
-{URI}       { yylval->uri = {yytext, (size_t) yyleng}; return URI; }
+{SPATH}     { yylval->path = strdup(yytext); return SPATH; }
+{URI}       { yylval->uri = strdup(yytext); return URI; }

 [ \t\r\n]+    /* eat up whitespace */
 \#[^\r\n]*    /* single-line comments */
@@ -191,7 +191,7 @@ void ExprConcatStrings::show(std::ostream & str) const
    str << "(";
    for (auto & i : *es) {
        if (first) first = false; else str << " + ";
-        str << *i.second;
+        str << *i;
    }
    str << ")";
 }
@@ -439,7 +439,7 @@ void ExprOpNot::bindVars(const StaticEnv & env)
 void ExprConcatStrings::bindVars(const StaticEnv & env)
 {
    for (auto & i : *es)
-        i.second->bindVars(env);
+        i->bindVars(env);
 }

 void ExprPos::bindVars(const StaticEnv & env)
@@ -473,7 +473,7 @@ string ExprLambda::showNamePos() const
 size_t SymbolTable::totalSize() const
 {
    size_t n = 0;
-    for (auto & i : store)
+    for (auto & i : symbols)
        n += i.size();
    return n;
 }
@@ -94,7 +94,7 @@ struct ExprInt : Expr
 {
    NixInt n;
    Value v;
-    ExprInt(NixInt n) : n(n) { v.mkInt(n); };
+    ExprInt(NixInt n) : n(n) { mkInt(v, n); };
    COMMON_METHODS
    Value * maybeThunk(EvalState & state, Env & env);
 };
@@ -103,7 +103,7 @@ struct ExprFloat : Expr
 {
    NixFloat nf;
    Value v;
-    ExprFloat(NixFloat nf) : nf(nf) { v.mkFloat(nf); };
+    ExprFloat(NixFloat nf) : nf(nf) { mkFloat(v, nf); };
    COMMON_METHODS
    Value * maybeThunk(EvalState & state, Env & env);
 };
@@ -112,7 +112,7 @@ struct ExprString : Expr
 {
    Symbol s;
    Value v;
-    ExprString(const Symbol & s) : s(s) { v.mkString(s); };
+    ExprString(const Symbol & s) : s(s) { mkString(v, s); };
    COMMON_METHODS
    Value * maybeThunk(EvalState & state, Env & env);
 };
@@ -332,8 +332,8 @@ struct ExprConcatStrings : Expr
 {
    Pos pos;
    bool forceString;
-    vector<std::pair<Pos, Expr *> > * es;
-    ExprConcatStrings(const Pos & pos, bool forceString, vector<std::pair<Pos, Expr *> > * es)
+    vector<Expr *> * es;
+    ExprConcatStrings(const Pos & pos, bool forceString, vector<Expr *> * es)
        : pos(pos), forceString(forceString), es(es) { };
    COMMON_METHODS
 };
@@ -364,21 +364,10 @@ struct StaticEnv

    void sort()
    {
-        std::stable_sort(vars.begin(), vars.end(),
+        std::sort(vars.begin(), vars.end(),
            [](const Vars::value_type & a, const Vars::value_type & b) { return a.first < b.first; });
    }

-    void deduplicate()
-    {
-        auto it = vars.begin(), jt = it, end = vars.end();
-        while (jt != end) {
-            *it = *jt++;
-            while (jt != end && it->first == jt->first) *it = *jt++;
-            it++;
-        }
-        vars.erase(it, end);
-    }
-
    Vars::const_iterator find(const Symbol & name) const
    {
        Vars::value_type key(name, 0);
@@ -152,7 +152,7 @@ static void addFormal(const Pos & pos, Formals * formals, const Formal & formal)
 }


-static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<std::pair<Pos, Expr *> > & es)
+static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<Expr *> & es)
 {
    if (es.empty()) return new ExprString(symbols.create(""));

@@ -162,7 +162,7 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<st
    bool atStartOfLine = true; /* = seen only whitespace in the current line */
    size_t minIndent = 1000000;
    size_t curIndent = 0;
-    for (auto & [i_pos, i] : es) {
+    for (auto & i : es) {
        ExprIndStr * e = dynamic_cast<ExprIndStr *>(i);
        if (!e) {
            /* Anti-quotations end the current start-of-line whitespace. */
@@ -192,12 +192,12 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<st
    }

    /* Strip spaces from each line. */
-    vector<std::pair<Pos, Expr *> > * es2 = new vector<std::pair<Pos, Expr *> >;
+    vector<Expr *> * es2 = new vector<Expr *>;
    atStartOfLine = true;
    size_t curDropped = 0;
    size_t n = es.size();
-    for (vector<std::pair<Pos, Expr *> >::iterator i = es.begin(); i != es.end(); ++i, --n) {
-        ExprIndStr * e = dynamic_cast<ExprIndStr *>(i->second);
+    for (vector<Expr *>::iterator i = es.begin(); i != es.end(); ++i, --n) {
+        ExprIndStr * e = dynamic_cast<ExprIndStr *>(*i);
        if (!e) {
            atStartOfLine = false;
            curDropped = 0;
@@ -234,11 +234,11 @@ static Expr * stripIndentation(const Pos & pos, SymbolTable & symbols, vector<st
                s2 = string(s2, 0, p + 1);
        }

-        es2->emplace_back(i->first, new ExprString(symbols.create(s2)));
+        es2->push_back(new ExprString(symbols.create(s2)));
    }

    /* If this is a single string, then don't do a concatenation. */
-    return es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0].second) ? (*es2)[0].second : new ExprConcatStrings(pos, true, es2);
+    return es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0]) ? (*es2)[0] : new ExprConcatStrings(pos, true, es2);
 }


@@ -273,18 +273,11 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParseData * data, const char * err
  nix::Formal * formal;
  nix::NixInt n;
  nix::NixFloat nf;
-  // using C a struct allows us to avoid having to define the special
-  // members that using string_view here would implicitly delete.
-  struct StringToken {
-    const char * p;
-    size_t l;
-    operator std::string_view() const { return {p, l}; }
-  };
-  StringToken id; // !!! -> Symbol
-  StringToken path;
-  StringToken uri;
+  const char * id; // !!! -> Symbol
+  char * path;
+  char * uri;
  std::vector<nix::AttrName> * attrNames;
-  std::vector<std::pair<nix::Pos, nix::Expr *> > * string_parts;
+  std::vector<nix::Expr *> * string_parts;
 }

 %type <e> start expr expr_function expr_if expr_op
@@ -371,7 +364,7 @@ expr_op
  | expr_op UPDATE expr_op { $$ = new ExprOpUpdate(CUR_POS, $1, $3); }
  | expr_op '?' attrpath { $$ = new ExprOpHasAttr($1, *$3); }
  | expr_op '+' expr_op
-    { $$ = new ExprConcatStrings(CUR_POS, false, new vector<std::pair<Pos, Expr *> >({{makeCurPos(@1, data), $1}, {makeCurPos(@3, data), $3}})); }
+    { $$ = new ExprConcatStrings(CUR_POS, false, new vector<Expr *>({$1, $3})); }
  | expr_op '-' expr_op { $$ = new ExprCall(CUR_POS, new ExprVar(data->symbols.create("__sub")), {$1, $3}); }
  | expr_op '*' expr_op { $$ = new ExprCall(CUR_POS, new ExprVar(data->symbols.create("__mul")), {$1, $3}); }
  | expr_op '/' expr_op { $$ = new ExprCall(CUR_POS, new ExprVar(data->symbols.create("__div")), {$1, $3}); }
@@ -404,8 +397,7 @@ expr_select

 expr_simple
  : ID {
-      std::string_view s = "__curPos";
-      if ($1.l == s.size() && strncmp($1.p, s.data(), s.size()) == 0)
+      if (strcmp($1, "__curPos") == 0)
          $$ = new ExprPos(CUR_POS);
      else
          $$ = new ExprVar(CUR_POS, data->symbols.create($1));
@@ -418,11 +410,11 @@ expr_simple
  }
  | path_start PATH_END { $$ = $1; }
  | path_start string_parts_interpolated PATH_END {
-      $2->insert($2->begin(), {makeCurPos(@1, data), $1});
+      $2->insert($2->begin(), $1);
      $$ = new ExprConcatStrings(CUR_POS, false, $2);
  }
  | SPATH {
-      string path($1.p + 1, $1.l - 2);
+      string path($1 + 1, strlen($1) - 2);
      $$ = new ExprCall(CUR_POS,
          new ExprVar(data->symbols.create("__findFile")),
          {new ExprVar(data->symbols.create("__nixPath")),
@@ -456,34 +448,34 @@ string_parts
  ;

 string_parts_interpolated
-  : string_parts_interpolated STR { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $2); }
-  | string_parts_interpolated DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $3); }
-  | DOLLAR_CURLY expr '}' { $$ = new vector<std::pair<Pos, Expr *> >; $$->emplace_back(makeCurPos(@1, data), $2); }
+  : string_parts_interpolated STR { $$ = $1; $1->push_back($2); }
+  | string_parts_interpolated DOLLAR_CURLY expr '}' { $$ = $1; $1->push_back($3); }
+  | DOLLAR_CURLY expr '}' { $$ = new vector<Expr *>; $$->push_back($2); }
  | STR DOLLAR_CURLY expr '}' {
-      $$ = new vector<std::pair<Pos, Expr *> >;
-      $$->emplace_back(makeCurPos(@1, data), $1);
-      $$->emplace_back(makeCurPos(@2, data), $3);
+      $$ = new vector<Expr *>;
+      $$->push_back($1);
+      $$->push_back($3);
    }
  ;

 path_start
  : PATH {
-    Path path(absPath({$1.p, $1.l}, data->basePath));
+    Path path(absPath($1, data->basePath));
    /* add back in the trailing '/' to the first segment */
-    if ($1.p[$1.l-1] == '/' && $1.l > 1)
+    if ($1[strlen($1)-1] == '/' && strlen($1) > 1)
      path += "/";
    $$ = new ExprPath(path);
  }
  | HPATH {
-    Path path(getHome() + string($1.p + 1, $1.l - 1));
+    Path path(getHome() + string($1 + 1));
    $$ = new ExprPath(path);
  }
  ;

 ind_string_parts
-  : ind_string_parts IND_STR { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $2); }
-  | ind_string_parts DOLLAR_CURLY expr '}' { $$ = $1; $1->emplace_back(makeCurPos(@2, data), $3); }
-  | { $$ = new vector<std::pair<Pos, Expr *> >; }
+  : ind_string_parts IND_STR { $$ = $1; $1->push_back($2); }
+  | ind_string_parts DOLLAR_CURLY expr '}' { $$ = $1; $1->push_back($3); }
+  | { $$ = new vector<Expr *>; }
  ;

 binds
@@ -551,7 +543,7 @@ attrpath

 attr
  : ID { $$ = $1; }
-  | OR_KW { $$ = {"or", 2}; }
+  | OR_KW { $$ = "or"; }
  ;

 string_attr
@@ -597,7 +589,7 @@ formal
 namespace nix {


-Expr * EvalState::parse(char * text, size_t length, FileOrigin origin,
+Expr * EvalState::parse(const char * text, FileOrigin origin,
    const Path & path, const Path & basePath, StaticEnv & staticEnv)
 {
    yyscan_t scanner;
@@ -617,7 +609,7 @@ Expr * EvalState::parse(char * text, size_t length, FileOrigin origin,
    data.basePath = basePath;

    yylex_init(&scanner);
-    yy_scan_buffer(text, length, scanner);
+    yy_scan_string(text, scanner);
    int res = yyparse(scanner, &data);
    yylex_destroy(scanner);

@@ -663,33 +655,26 @@ Expr * EvalState::parseExprFromFile(const Path & path)

 Expr * EvalState::parseExprFromFile(const Path & path, StaticEnv & staticEnv)
 {
-    auto buffer = readFile(path);
-    // readFile should have left some extra space for terminators
-    buffer.append("\0\0", 2);
-    return parse(buffer.data(), buffer.size(), foFile, path, dirOf(path), staticEnv);
+    return parse(readFile(path).c_str(), foFile, path, dirOf(path), staticEnv);
 }


-Expr * EvalState::parseExprFromString(std::string s, const Path & basePath, StaticEnv & staticEnv)
+Expr * EvalState::parseExprFromString(std::string_view s, const Path & basePath, StaticEnv & staticEnv)
 {
-    s.append("\0\0", 2);
-    return parse(s.data(), s.size(), foString, "", basePath, staticEnv);
+    return parse(s.data(), foString, "", basePath, staticEnv);
 }


-Expr * EvalState::parseExprFromString(std::string s, const Path & basePath)
+Expr * EvalState::parseExprFromString(std::string_view s, const Path & basePath)
 {
-    return parseExprFromString(std::move(s), basePath, staticBaseEnv);
+    return parseExprFromString(s, basePath, staticBaseEnv);
 }


 Expr * EvalState::parseStdin()
 {
    //Activity act(*logger, lvlTalkative, format("parsing standard input"));
-    auto buffer = drainFD(0);
-    // drainFD should have left some extra space for terminators
-    buffer.append("\0\0", 2);
-    return parse(buffer.data(), buffer.size(), foStdin, "", absPath("."), staticBaseEnv);
+    return parse(drainFD(0).data(), foStdin, "", absPath("."), staticBaseEnv);
 }


@@ -7,7 +7,8 @@ namespace nix {
 static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
    PathSet context;
-    v.mkString(state.coerceToString(pos, *args[0], context));
+    string s = state.coerceToString(pos, *args[0], context);
+    mkString(v, s, PathSet());
 }

 static RegisterPrimOp primop_unsafeDiscardStringContext("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext);
@@ -17,7 +18,7 @@ static void prim_hasContext(EvalState & state, const Pos & pos, Value * * args,
 {
    PathSet context;
    state.forceString(*args[0], context, pos);
-    v.mkBool(!context.empty());
+    mkBool(v, !context.empty());
 }

 static RegisterPrimOp primop_hasContext("__hasContext", 1, prim_hasContext);
@@ -38,7 +39,7 @@ static void prim_unsafeDiscardOutputDependency(EvalState & state, const Pos & po
    for (auto & p : context)
        context2.insert(p.at(0) == '=' ? string(p, 1) : p);

-    v.mkString(s, context2);
+    mkString(v, s, context2);
 }

 static RegisterPrimOp primop_unsafeDiscardOutputDependency("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
@@ -102,26 +103,27 @@ static void prim_getContext(EvalState & state, const Pos & pos, Value * * args,
        }
    }

-    auto attrs = state.buildBindings(contextInfos.size());
+    state.mkAttrs(v, contextInfos.size());

    auto sPath = state.symbols.create("path");
    auto sAllOutputs = state.symbols.create("allOutputs");
    for (const auto & info : contextInfos) {
-        auto infoAttrs = state.buildBindings(3);
+        auto & infoVal = *state.allocAttr(v, state.symbols.create(info.first));
+        state.mkAttrs(infoVal, 3);
        if (info.second.path)
-            infoAttrs.alloc(sPath).mkBool(true);
+            mkBool(*state.allocAttr(infoVal, sPath), true);
        if (info.second.allOutputs)
-            infoAttrs.alloc(sAllOutputs).mkBool(true);
+            mkBool(*state.allocAttr(infoVal, sAllOutputs), true);
        if (!info.second.outputs.empty()) {
-            auto & outputsVal = infoAttrs.alloc(state.sOutputs);
+            auto & outputsVal = *state.allocAttr(infoVal, state.sOutputs);
            state.mkList(outputsVal, info.second.outputs.size());
-            for (const auto & [i, output] : enumerate(info.second.outputs))
-                (outputsVal.listElems()[i] = state.allocValue())->mkString(output);
+            size_t i = 0;
+            for (const auto & output : info.second.outputs)
+                mkString(*(outputsVal.listElems()[i++] = state.allocValue()), output);
        }
-        attrs.alloc(info.first).mkAttrs(infoAttrs);
+        infoVal.attrs->sort();
    }
-
-    v.mkAttrs(attrs);
+    v.attrs->sort();
 }

 static RegisterPrimOp primop_getContext("__getContext", 1, prim_getContext);
@@ -185,7 +187,7 @@ static void prim_appendContext(EvalState & state, const Pos & pos, Value * * arg
        }
    }

-    v.mkString(orig, context);
+    mkString(v, orig, context);
 }

 static RegisterPrimOp primop_appendContext("__appendContext", 2, prim_appendContext);
@@ -70,19 +70,19 @@ static void prim_fetchMercurial(EvalState & state, const Pos & pos, Value * * ar
    // FIXME: use name
    auto [tree, input2] = input.fetch(state.store);

-    auto attrs2 = state.buildBindings(8);
+    state.mkAttrs(v, 8);
    auto storePath = state.store->printStorePath(tree.storePath);
-    attrs2.alloc(state.sOutPath).mkString(storePath, {storePath});
+    mkString(*state.allocAttr(v, state.sOutPath), storePath, PathSet({storePath}));
    if (input2.getRef())
-        attrs2.alloc("branch").mkString(*input2.getRef());
+        mkString(*state.allocAttr(v, state.symbols.create("branch")), *input2.getRef());
    // Backward compatibility: set 'rev' to
    // 0000000000000000000000000000000000000000 for a dirty tree.
    auto rev2 = input2.getRev().value_or(Hash(htSHA1));
-    attrs2.alloc("rev").mkString(rev2.gitRev());
-    attrs2.alloc("shortRev").mkString(rev2.gitRev().substr(0, 12));
+    mkString(*state.allocAttr(v, state.symbols.create("rev")), rev2.gitRev());
+    mkString(*state.allocAttr(v, state.symbols.create("shortRev")), std::string(rev2.gitRev(), 0, 12));
    if (auto revCount = input2.getRevCount())
-        attrs2.alloc("revCount").mkInt(*revCount);
-    v.mkAttrs(attrs2);
+        mkInt(*state.allocAttr(v, state.symbols.create("revCount")), *revCount);
+    v.attrs->sort();

    state.allowPath(tree.storePath);
 }
@@ -21,48 +21,49 @@ void emitTreeAttrs(
 {
    assert(input.isImmutable());

-    auto attrs = state.buildBindings(8);
+    state.mkAttrs(v, 8);

    auto storePath = state.store->printStorePath(tree.storePath);

-    attrs.alloc(state.sOutPath).mkString(storePath, {storePath});
+    mkString(*state.allocAttr(v, state.sOutPath), storePath, PathSet({storePath}));

    // FIXME: support arbitrary input attributes.

    auto narHash = input.getNarHash();
    assert(narHash);
-    attrs.alloc("narHash").mkString(narHash->to_string(SRI, true));
+    mkString(*state.allocAttr(v, state.symbols.create("narHash")),
+        narHash->to_string(SRI, true));

    if (input.getType() == "git")
-        attrs.alloc("submodules").mkBool(
+        mkBool(*state.allocAttr(v, state.symbols.create("submodules")),
            fetchers::maybeGetBoolAttr(input.attrs, "submodules").value_or(false));

    if (!forceDirty) {

        if (auto rev = input.getRev()) {
-            attrs.alloc("rev").mkString(rev->gitRev());
-            attrs.alloc("shortRev").mkString(rev->gitShortRev());
+            mkString(*state.allocAttr(v, state.symbols.create("rev")), rev->gitRev());
+            mkString(*state.allocAttr(v, state.symbols.create("shortRev")), rev->gitShortRev());
        } else if (emptyRevFallback) {
            // Backwards compat for `builtins.fetchGit`: dirty repos return an empty sha1 as rev
            auto emptyHash = Hash(htSHA1);
-            attrs.alloc("rev").mkString(emptyHash.gitRev());
-            attrs.alloc("shortRev").mkString(emptyHash.gitShortRev());
+            mkString(*state.allocAttr(v, state.symbols.create("rev")), emptyHash.gitRev());
+            mkString(*state.allocAttr(v, state.symbols.create("shortRev")), emptyHash.gitShortRev());
        }

        if (auto revCount = input.getRevCount())
-            attrs.alloc("revCount").mkInt(*revCount);
+            mkInt(*state.allocAttr(v, state.symbols.create("revCount")), *revCount);
        else if (emptyRevFallback)
-            attrs.alloc("revCount").mkInt(0);
+            mkInt(*state.allocAttr(v, state.symbols.create("revCount")), 0);

    }

    if (auto lastModified = input.getLastModified()) {
-        attrs.alloc("lastModified").mkInt(*lastModified);
-        attrs.alloc("lastModifiedDate").mkString(
+        mkInt(*state.allocAttr(v, state.symbols.create("lastModified")), *lastModified);
+        mkString(*state.allocAttr(v, state.symbols.create("lastModifiedDate")),
            fmt("%s", std::put_time(std::gmtime(&*lastModified), "%Y%m%d%H%M%S")));
    }

-    v.mkAttrs(attrs);
+    v.attrs->sort();
 }

 std::string fixURI(std::string uri, EvalState & state, const std::string & defaultScheme = "file")
@@ -247,7 +248,7 @@ static void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
    state.allowPath(storePath);

    auto path = state.store->printStorePath(storePath);
-    v.mkString(path, PathSet({path}));
+    mkString(v, path, PathSet({path}));
 }

 static void prim_fetchurl(EvalState & state, const Pos & pos, Value * * args, Value & v)
@@ -1,76 +1,86 @@
 #include "primops.hh"
 #include "eval-inline.hh"

-#include "../../toml11/toml.hpp"
+#include "../../cpptoml/cpptoml.h"

 namespace nix {

-static void prim_fromTOML(EvalState & state, const Pos & pos, Value * * args, Value & val)
+static void prim_fromTOML(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
+    using namespace cpptoml;
+
    auto toml = state.forceStringNoCtx(*args[0], pos);

    std::istringstream tomlStream(toml);

-    std::function<void(Value &, toml::value)> visit;
+    std::function<void(Value &, std::shared_ptr<base>)> visit;

-    visit = [&](Value & v, toml::value t) {
+    visit = [&](Value & v, std::shared_ptr<base> t) {

-        switch(t.type())
-        {
-            case toml::value_t::table:
-                {
-                    auto table = toml::get<toml::table>(t);
+        if (auto t2 = t->as_table()) {

-                    size_t size = 0;
-                    for (auto & i : table) { (void) i; size++; }
+            size_t size = 0;
+            for (auto & i : *t2) { (void) i; size++; }

-                    auto attrs = state.buildBindings(size);
+            state.mkAttrs(v, size);

-                    for(auto & elem : table)
-                        visit(attrs.alloc(elem.first), elem.second);
+            for (auto & i : *t2) {
+                auto & v2 = *state.allocAttr(v, state.symbols.create(i.first));

-                    v.mkAttrs(attrs);
+                if (auto i2 = i.second->as_table_array()) {
+                    size_t size2 = i2->get().size();
+                    state.mkList(v2, size2);
+                    for (size_t j = 0; j < size2; ++j)
+                        visit(*(v2.listElems()[j] = state.allocValue()), i2->get()[j]);
                }
-                break;;
-            case toml::value_t::array:
-                {
-                    auto array = toml::get<std::vector<toml::value>>(t);
-
-                    size_t size = array.size();
-                    state.mkList(v, size);
-                    for (size_t i = 0; i < size; ++i)
-                        visit(*(v.listElems()[i] = state.allocValue()), array[i]);
-                }
-                break;;
-            case toml::value_t::boolean:
-                v.mkBool(toml::get<bool>(t));
-                break;;
-            case toml::value_t::integer:
-                v.mkInt(toml::get<int64_t>(t));
-                break;;
-            case toml::value_t::floating:
-                v.mkFloat(toml::get<NixFloat>(t));
-                break;;
-            case toml::value_t::string:
-                v.mkString(toml::get<std::string>(t));
-                break;;
-            case toml::value_t::local_datetime:
-            case toml::value_t::offset_datetime:
-            case toml::value_t::local_date:
-            case toml::value_t::local_time:
-                // We fail since Nix doesn't have date and time types
-                throw std::runtime_error("Dates and times are not supported");
-                break;;
-            case toml::value_t::empty:
-                v.mkNull();
-                break;;
+                else
+                    visit(v2, i.second);
+            }

+            v.attrs->sort();
        }
+
+        else if (auto t2 = t->as_array()) {
+            size_t size = t2->get().size();
+
+            state.mkList(v, size);
+
+            for (size_t i = 0; i < size; ++i)
+                visit(*(v.listElems()[i] = state.allocValue()), t2->get()[i]);
+        }
+
+        // Handle cases like 'a = [[{ a = true }]]', which IMHO should be
+        // parsed as a array containing an array containing a table,
+        // but instead are parsed as an array containing a table array
+        // containing a table.
+        else if (auto t2 = t->as_table_array()) {
+            size_t size = t2->get().size();
+
+            state.mkList(v, size);
+
+            for (size_t j = 0; j < size; ++j)
+                visit(*(v.listElems()[j] = state.allocValue()), t2->get()[j]);
+        }
+
+        else if (t->is_value()) {
+            if (auto val = t->as<int64_t>())
+                mkInt(v, val->get());
+            else if (auto val = t->as<NixFloat>())
+                mkFloat(v, val->get());
+            else if (auto val = t->as<bool>())
+                mkBool(v, val->get());
+            else if (auto val = t->as<std::string>())
+                mkString(v, val->get());
+            else
+                throw EvalError("unsupported value type in TOML");
+        }
+
+        else abort();
    };

    try {
-        visit(val, toml::parse(tomlStream, "fromTOML" /* the "filename" */));
-    } catch (std::exception & e) { // TODO: toml::syntax_error
+        visit(v, parser(tomlStream).parse());
+    } catch (std::runtime_error & e) {
        throw EvalError({
            .msg = hintfmt("while parsing a TOML string: %s", e.what()),
            .errPos = pos
@@ -1,8 +1,7 @@
 #pragma once

-#include <list>
 #include <map>
-#include <unordered_map>
+#include <unordered_set>

 #include "types.hh"

@@ -71,21 +70,15 @@ public:
 class SymbolTable
 {
 private:
-    std::unordered_map<std::string_view, Symbol> symbols;
-    std::list<string> store;
+    typedef std::unordered_set<string> Symbols;
+    Symbols symbols;

 public:
    Symbol create(std::string_view s)
    {
-        // Most symbols are looked up more than once, so we trade off insertion performance
-        // for lookup performance.
-        // TODO: could probably be done more efficiently with transparent Hash and Equals
-        // on the original implementation using unordered_set
-        auto it = symbols.find(s);
-        if (it != symbols.end()) return it->second;
-
-        const string & rawSym = store.emplace_back(s);
-        return symbols.emplace(rawSym, Symbol(&rawSym)).first->second;
+        // FIXME: avoid allocation if 's' already exists in the symbol table.
+        std::pair<Symbols::iterator, bool> res = symbols.emplace(std::string(s));
+        return Symbol(&*res.first);
    }

    size_t size() const
@@ -98,7 +91,7 @@ public:
    template<typename T>
    void dump(T callback)
    {
-        for (auto & s : store)
+        for (auto & s : symbols)
            callback(s);
    }
 };
@@ -10,8 +10,6 @@

 namespace nix {

-class BindingsBuilder;
-

 typedef enum {
    tInt = 1,
@@ -237,17 +235,6 @@ public:
        string.context = context;
    }

-    void mkString(std::string_view s);
-
-    void mkString(std::string_view s, const PathSet & context);
-
-    void mkStringMove(const char * s, const PathSet & context);
-
-    inline void mkString(const Symbol & s)
-    {
-        mkString(((const std::string &) s).c_str());
-    }
-
    inline void mkPath(const char * s)
    {
        clearValue();
@@ -255,8 +242,6 @@ public:
        path = s;
    }

-    void mkPath(std::string_view s);
-
    inline void mkNull()
    {
        clearValue();
@@ -270,8 +255,6 @@ public:
        attrs = a;
    }

-    Value & mkAttrs(BindingsBuilder & bindings);
-
    inline void mkList(size_t size)
    {
        clearValue();
@@ -400,14 +383,51 @@ public:
 };


+
+// TODO: Remove these static functions, replace call sites with v.mk* instead
+static inline void mkInt(Value & v, NixInt n)
+{
+    v.mkInt(n);
+}
+
+static inline void mkFloat(Value & v, NixFloat n)
+{
+    v.mkFloat(n);
+}
+
+static inline void mkBool(Value & v, bool b)
+{
+    v.mkBool(b);
+}
+
+static inline void mkNull(Value & v)
+{
+    v.mkNull();
+}
+
+static inline void mkApp(Value & v, Value & left, Value & right)
+{
+    v.mkApp(&left, &right);
+}
+
+static inline void mkString(Value & v, const Symbol & s)
+{
+    v.mkString(((const string &) s).c_str());
+}
+
+
+void mkString(Value & v, const char * s);
+
+
+void mkPath(Value & v, const char * s);
+
+
 #if HAVE_BOEHMGC
 typedef std::vector<Value *, traceable_allocator<Value *> > ValueVector;
 typedef std::map<Symbol, Value *, std::less<Symbol>, traceable_allocator<std::pair<const Symbol, Value *> > > ValueMap;
-typedef std::map<Symbol, ValueVector, std::less<Symbol>, traceable_allocator<std::pair<const Symbol, ValueVector> > > ValueVectorMap;
 #else
 typedef std::vector<Value *> ValueVector;
 typedef std::map<Symbol, Value *> ValueMap;
-typedef std::map<Symbol, ValueVector> ValueVectorMap;
 #endif


@@ -97,7 +97,7 @@ struct PathInputScheme : InputScheme
            // for security, ensure that if the parent is a store path, it's inside it
            if (store->isInStore(parent)) {
                auto storePath = store->printStorePath(store->toStorePath(parent).first);
-                if (!isDirOrInDir(absPath, storePath))
+                if (!isInDir(absPath, storePath))
                    throw BadStorePath("relative path '%s' points outside of its parent's store path '%s'", path, storePath);
            }
        } else
@@ -67,18 +67,18 @@ DownloadFileResult downloadFile(
        storePath = std::move(cached->storePath);
    } else {
        StringSink sink;
-        dumpString(res.data, sink);
-        auto hash = hashString(htSHA256, res.data);
+        dumpString(*res.data, sink);
+        auto hash = hashString(htSHA256, *res.data);
        ValidPathInfo info {
            store->makeFixedOutputPath(FileIngestionMethod::Flat, hash, name),
-            hashString(htSHA256, sink.s),
+            hashString(htSHA256, *sink.s),
        };
-        info.narSize = sink.s.size();
+        info.narSize = sink.s->size();
        info.ca = FixedOutputHash {
            .method = FileIngestionMethod::Flat,
            .hash = hash,
        };
-        auto source = StringSource(sink.s);
+        auto source = StringSource { *sink.s };
        store->addToStore(info, source, NoRepair, NoCheckSigs);
        storePath = std::move(info.path);
    }
@@ -176,7 +176,6 @@ struct TarballInputScheme : InputScheme

        if (!hasSuffix(url.path, ".zip")
            && !hasSuffix(url.path, ".tar")
-            && !hasSuffix(url.path, ".tgz")
            && !hasSuffix(url.path, ".tar.gz")
            && !hasSuffix(url.path, ".tar.xz")
            && !hasSuffix(url.path, ".tar.bz2")
@@ -11,7 +11,7 @@

 namespace nix {

-static std::string_view getS(const std::vector<Logger::Field> & fields, size_t n)
+static std::string getS(const std::vector<Logger::Field> & fields, size_t n)
 {
    assert(n < fields.size());
    assert(fields[n].type == Logger::Field::tString);
@@ -145,10 +145,10 @@ static void preloadNSS() {
         *
         * All other platforms are unaffected.
         */
-        if (!dlopen(LIBNSS_DNS_SO, RTLD_NOW))
-            warn("unable to load nss_dns backend");
-        // FIXME: get hosts entry from nsswitch.conf.
-        __nss_configure_lookup("hosts", "files dns");
+        if (dlopen (LIBNSS_DNS_SO, RTLD_NOW) == NULL) {
+            printMsg(Verbosity::lvlWarn, fmt("Unable to load nss_dns backend"));
+        }
+        __nss_configure_lookup ("hosts", "dns");
 #endif
    });
 }
@@ -427,7 +427,7 @@ RunPager::RunPager()
    });

    pid.setKillSignal(SIGINT);
-    stdout = fcntl(STDOUT_FILENO, F_DUPFD_CLOEXEC, 0);
+
    if (dup2(toPager.writeSide.get(), STDOUT_FILENO) == -1)
        throw SysError("dupping stdout");
 }
@@ -438,7 +438,7 @@ RunPager::~RunPager()
    try {
        if (pid != -1) {
            std::cout.flush();
-            dup2(stdout, STDOUT_FILENO);
+            close(STDOUT_FILENO);
            pid.wait();
        }
    } catch (...) {
@@ -88,7 +88,6 @@ public:

 private:
    Pid pid;
-    int stdout;
 };

 extern volatile ::sig_atomic_t blockInt;
@@ -31,7 +31,7 @@ BinaryCacheStore::BinaryCacheStore(const Params & params)

    StringSink sink;
    sink << narVersionMagic1;
-    narMagic = sink.s;
+    narMagic = *sink.s;
 }

 void BinaryCacheStore::init()
@@ -68,7 +68,7 @@ void BinaryCacheStore::upsertFile(const std::string & path,
 }

 void BinaryCacheStore::getFile(const std::string & path,
-    Callback<std::optional<std::string>> callback) noexcept
+    Callback<std::shared_ptr<std::string>> callback) noexcept
 {
    try {
        callback(getFile(path));
@@ -77,9 +77,9 @@ void BinaryCacheStore::getFile(const std::string & path,

 void BinaryCacheStore::getFile(const std::string & path, Sink & sink)
 {
-    std::promise<std::optional<std::string>> promise;
+    std::promise<std::shared_ptr<std::string>> promise;
    getFile(path,
-        {[&](std::future<std::optional<std::string>> result) {
+        {[&](std::future<std::shared_ptr<std::string>> result) {
            try {
                promise.set_value(result.get());
            } catch (...) {
@@ -89,15 +89,15 @@ void BinaryCacheStore::getFile(const std::string & path, Sink & sink)
    sink(*promise.get_future().get());
 }

-std::optional<std::string> BinaryCacheStore::getFile(const std::string & path)
+std::shared_ptr<std::string> BinaryCacheStore::getFile(const std::string & path)
 {
    StringSink sink;
    try {
        getFile(path, sink);
    } catch (NoSuchBinaryCacheFile &) {
-        return std::nullopt;
+        return nullptr;
    }
-    return std::move(sink.s);
+    return sink.s;
 }

 std::string BinaryCacheStore::narInfoFileFor(const StorePath & storePath)
@@ -367,11 +367,11 @@ void BinaryCacheStore::queryPathInfoUncached(const StorePath & storePath,
    auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));

    getFile(narInfoFile,
-        {[=](std::future<std::optional<std::string>> fut) {
+        {[=](std::future<std::shared_ptr<std::string>> fut) {
            try {
                auto data = fut.get();

-                if (!data) return (*callbackPtr)({});
+                if (!data) return (*callbackPtr)(nullptr);

                stats.narInfoRead++;

@@ -429,7 +429,7 @@ StorePath BinaryCacheStore::addTextToStore(const string & name, const string & s

    StringSink sink;
    dumpString(s, sink);
-    StringSource source(sink.s);
+    auto source = StringSource { *sink.s };
    return addToStoreCommon(source, repair, CheckSigs, [&](HashResult nar) {
        ValidPathInfo info { path, nar.first };
        info.narSize = nar.second;
@@ -446,11 +446,11 @@ void BinaryCacheStore::queryRealisationUncached(const DrvOutput & id,

    auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));

-    Callback<std::optional<std::string>> newCallback = {
-        [=](std::future<std::optional<std::string>> fut) {
+    Callback<std::shared_ptr<std::string>> newCallback = {
+        [=](std::future<std::shared_ptr<std::string>> fut) {
            try {
                auto data = fut.get();
-                if (!data) return (*callbackPtr)({});
+                if (!data) return (*callbackPtr)(nullptr);

                auto realisation = Realisation::fromJSON(
                    nlohmann::json::parse(*data), outputInfoFilePath);
@@ -490,7 +490,7 @@ void BinaryCacheStore::addSignatures(const StorePath & storePath, const StringSe
    writeNarInfo(narInfo);
 }

-std::optional<std::string> BinaryCacheStore::getBuildLog(const StorePath & path)
+std::shared_ptr<std::string> BinaryCacheStore::getBuildLog(const StorePath & path)
 {
    auto drvPath = path;

@@ -498,10 +498,10 @@ std::optional<std::string> BinaryCacheStore::getBuildLog(const StorePath & path)
        try {
            auto info = queryPathInfo(path);
            // FIXME: add a "Log" field to .narinfo
-            if (!info->deriver) return std::nullopt;
+            if (!info->deriver) return nullptr;
            drvPath = *info->deriver;
        } catch (InvalidPath &) {
-            return std::nullopt;
+            return nullptr;
        }
    }

@@ -512,14 +512,4 @@ std::optional<std::string> BinaryCacheStore::getBuildLog(const StorePath & path)
    return getFile(logPath);
 }

-void BinaryCacheStore::addBuildLog(const StorePath & drvPath, std::string_view log)
-{
-    assert(drvPath.isDerivation());
-
-    upsertFile(
-        "log/" + std::string(drvPath.to_string()),
-        (std::string) log, // FIXME: don't copy
-        "text/plain; charset=utf-8");
-}
-
 }
@@ -51,7 +51,6 @@ public:
        const std::string & mimeType) = 0;

    void upsertFile(const std::string & path,
-        // FIXME: use std::string_view
        std::string && data,
        const std::string & mimeType);

@@ -63,11 +62,10 @@ public:

    /* Fetch the specified file and call the specified callback with
       the result. A subclass may implement this asynchronously. */
-    virtual void getFile(
-        const std::string & path,
-        Callback<std::optional<std::string>> callback) noexcept;
+    virtual void getFile(const std::string & path,
+        Callback<std::shared_ptr<std::string>> callback) noexcept;

-    std::optional<std::string> getFile(const std::string & path);
+    std::shared_ptr<std::string> getFile(const std::string & path);

 public:

@@ -119,9 +117,7 @@ public:

    void addSignatures(const StorePath & storePath, const StringSet & sigs) override;

-    std::optional<std::string> getBuildLog(const StorePath & path) override;
-
-    void addBuildLog(const StorePath & drvPath, std::string_view log) override;
+    std::shared_ptr<std::string> getBuildLog(const StorePath & path) override;

 };

@@ -17,7 +17,6 @@
 #include <regex>
 #include <queue>

-#include <fstream>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
@@ -194,7 +193,7 @@ void DerivationGoal::loadDerivation()
    assert(worker.evalStore.isValidPath(drvPath));

    /* Get the derivation. */
-    drv = std::make_unique<Derivation>(worker.evalStore.readDerivation(drvPath));
+    drv = std::make_unique<Derivation>(worker.evalStore.derivationFromPath(drvPath));

    haveDerivation();
 }
@@ -278,7 +277,7 @@ void DerivationGoal::outputsSubstitutionTried()

    if (nrFailed > 0 && nrFailed > nrNoSubstituters + nrIncompleteClosure && !settings.tryFallback) {
        done(BuildResult::TransientFailure,
-            Error("some substitutes for the outputs of derivation '%s' failed (usually happens due to networking issues); try '--fallback' to build derivation from source ",
+            fmt("some substitutes for the outputs of derivation '%s' failed (usually happens due to networking issues); try '--fallback' to build derivation from source ",
                worker.store.printStorePath(drvPath)));
        return;
    }
@@ -465,6 +464,7 @@ void DerivationGoal::inputsRealised()
            Derivation drvResolved { *std::move(attempt) };

            auto pathResolved = writeDerivation(worker.store, drvResolved);
+            resolvedDrv = drvResolved;

            auto msg = fmt("Resolved derivation: '%s' -> '%s'",
                worker.store.printStorePath(drvPath),
@@ -475,9 +475,9 @@ void DerivationGoal::inputsRealised()
                       worker.store.printStorePath(pathResolved),
                   });

-            resolvedDrvGoal = worker.makeDerivationGoal(
+            auto resolvedGoal = worker.makeDerivationGoal(
                pathResolved, wantedOutputs, buildMode);
-            addWaitee(resolvedDrvGoal);
+            addWaitee(resolvedGoal);

            state = &DerivationGoal::resolvedFinished;
            return;
@@ -655,7 +655,7 @@ void DerivationGoal::tryLocalBuild() {
    throw Error(
        "unable to build with a primary store that isn't a local store; "
        "either pass a different '--store' or enable remote builds."
-        "\nhttps://nixos.org/manual/nix/stable/advanced-topics/distributed-builds.html");
+        "\nhttps://nixos.org/nix/manual/#chap-distributed-builds");
 }


@@ -938,17 +938,16 @@ void DerivationGoal::buildDone()
 }

 void DerivationGoal::resolvedFinished() {
-    assert(resolvedDrvGoal);
-    auto resolvedDrv = *resolvedDrvGoal->drv;
+    assert(resolvedDrv);

-    auto resolvedHashes = staticOutputHashes(worker.store, resolvedDrv);
+    auto resolvedHashes = staticOutputHashes(worker.store, *resolvedDrv);

    StorePathSet outputPaths;

    // `wantedOutputs` might be empty, which means “all the outputs”
    auto realWantedOutputs = wantedOutputs;
    if (realWantedOutputs.empty())
-        realWantedOutputs = resolvedDrv.outputNames();
+        realWantedOutputs = resolvedDrv->outputNames();

    for (auto & wantedOutput : realWantedOutputs) {
        assert(initialOutputs.count(wantedOutput) != 0);
@@ -980,17 +979,9 @@ void DerivationGoal::resolvedFinished() {
        outputPaths
    );

-    auto status = [&]() {
-        auto resolvedResult = resolvedDrvGoal->getResult();
-        switch (resolvedResult.status) {
-            case BuildResult::AlreadyValid:
-                return BuildResult::ResolvesToAlreadyValid;
-            default:
-                return resolvedResult.status;
-        }
-    }();
-
-    done(status);
+    // This is potentially a bit fishy in terms of error reporting. Not sure
+    // how to do it in a cleaner way
+    amDone(nrFailed == 0 ? ecSuccess : ecFailed, ex);
 }

 HookReply DerivationGoal::tryBuildHook()
@@ -1338,13 +1329,6 @@ void DerivationGoal::done(BuildResult::Status status, std::optional<Error> ex)
    }

    worker.updateProgress();
-
-    auto traceBuiltOutputsFile = getEnv("_NIX_TRACE_BUILT_OUTPUTS").value_or("");
-    if (traceBuiltOutputsFile != "") {
-        std::fstream fs;
-        fs.open(traceBuiltOutputsFile, std::fstream::out);
-        fs << worker.store.printStorePath(drvPath) << "\t" << result.toString() << std::endl;
-    }
 }


@@ -50,8 +50,8 @@ struct DerivationGoal : public Goal
    /* The path of the derivation. */
    StorePath drvPath;

-    /* The goal for the corresponding resolved derivation */
-    std::shared_ptr<DerivationGoal> resolvedDrvGoal;
+    /* The path of the corresponding resolved derivation */
+    std::optional<BasicDerivation> resolvedDrv;

    /* The specific outputs that we need to build.  Empty means all of
       them. */
@@ -260,7 +260,6 @@ void LocalDerivationGoal::cleanupHookFinally()
 void LocalDerivationGoal::cleanupPreChildKill()
 {
    sandboxMountNamespace = -1;
-    sandboxUserNamespace = -1;
 }


@@ -907,14 +906,11 @@ void LocalDerivationGoal::startBuilder()
                "nobody:x:65534:65534:Nobody:/:/noshell\n",
                sandboxUid(), sandboxGid(), settings.sandboxBuildDir));

-        /* Save the mount- and user namespace of the child. We have to do this
+        /* Save the mount namespace of the child. We have to do this
           *before* the child does a chroot. */
        sandboxMountNamespace = open(fmt("/proc/%d/ns/mnt", (pid_t) pid).c_str(), O_RDONLY);
        if (sandboxMountNamespace.get() == -1)
            throw SysError("getting sandbox mount namespace");
-        sandboxUserNamespace = open(fmt("/proc/%d/ns/user", (pid_t) pid).c_str(), O_RDONLY);
-        if (sandboxUserNamespace.get() == -1)
-            throw SysError("getting sandbox user namespace");

        /* Signal the builder that we've updated its user namespace. */
        writeFull(userNamespaceSync.writeSide.get(), "1");
@@ -1442,9 +1438,6 @@ void LocalDerivationGoal::addDependency(const StorePath & path)
                   child process.*/
                Pid child(startProcess([&]() {

-                    if (usingUserNamespace && (setns(sandboxUserNamespace.get(), 0) == -1))
-                        throw SysError("entering sandbox user namespace");
-
                    if (setns(sandboxMountNamespace.get(), 0) == -1)
                        throw SysError("entering sandbox mount namespace");

@@ -1786,14 +1779,11 @@ void LocalDerivationGoal::runChild()
           i686-linux build on an x86_64-linux machine. */
        struct utsname utsbuf;
        uname(&utsbuf);
-        if ((drv->platform == "i686-linux"
-                && (settings.thisSystem == "x86_64-linux"
-                    || (!strcmp(utsbuf.sysname, "Linux") && !strcmp(utsbuf.machine, "x86_64"))))
-            || drv->platform == "armv7l-linux"
-            || drv->platform == "armv6l-linux")
-        {
+        if (drv->platform == "i686-linux" &&
+            (settings.thisSystem == "x86_64-linux" ||
+             (!strcmp(utsbuf.sysname, "Linux") && !strcmp(utsbuf.machine, "x86_64")))) {
            if (personality(PER_LINUX32) == -1)
-                throw SysError("cannot set 32-bit personality");
+                throw SysError("cannot set i686-linux personality");
        }

        /* Impersonate a Linux 2.6 machine to get some determinism in
@@ -2226,8 +2216,8 @@ void LocalDerivationGoal::registerOutputs()
                StringSink sink;
                dumpPath(actualPath, sink);
                deletePath(actualPath);
-                sink.s = rewriteStrings(sink.s, outputRewrites);
-                StringSource source(sink.s);
+                sink.s = make_ref<std::string>(rewriteStrings(*sink.s, outputRewrites));
+                StringSource source(*sink.s);
                restorePath(actualPath, source);
            }
        };
@@ -2295,7 +2285,7 @@ void LocalDerivationGoal::registerOutputs()
                    StringSink sink;
                    dumpPath(actualPath, sink);
                    RewritingSink rsink2(oldHashPart, std::string(finalPath.hashPart()), nextSink);
-                    rsink2(sink.s);
+                    rsink2(*sink.s);
                    rsink2.flush();
                });
                Path tmpPath = actualPath + ".tmp";
@@ -2467,7 +2457,7 @@ void LocalDerivationGoal::registerOutputs()
        }

        if (curRound == nrRounds) {
-            localStore.optimisePath(actualPath, NoRepair); // FIXME: combine with scanForReferences()
+            localStore.optimisePath(actualPath); // FIXME: combine with scanForReferences()
            worker.markContentsGood(newInfo.path);
        }

@@ -27,10 +27,9 @@ struct LocalDerivationGoal : public DerivationGoal
    /* Pipe for synchronising updates to the builder namespaces. */
    Pipe userNamespaceSync;

-    /* The mount namespace and user namespace of the builder, used to add additional
+    /* The mount namespace of the builder, used to add additional
       paths to the sandbox as a result of recursive Nix calls. */
    AutoCloseFD sandboxMountNamespace;
-    AutoCloseFD sandboxUserNamespace;

    /* On Linux, whether we're doing the build in its own user
       namespace. */
@@ -138,8 +138,8 @@ void PathSubstitutionGoal::tryNext()
       only after we've downloaded the path. */
    if (!sub->isTrusted && worker.store.pathInfoIsUntrusted(*info))
    {
-        warn("the substitute for '%s' from '%s' is not signed by any of the keys in 'trusted-public-keys'",
-            worker.store.printStorePath(storePath), sub->getUri());
+        warn("substituter '%s' does not have a valid signature for path '%s'",
+            sub->getUri(), worker.store.printStorePath(storePath));
        tryNext();
        return;
    }
@@ -281,11 +281,11 @@ void Worker::run(const Goals & _topGoals)
                if (getMachines().empty())
                   throw Error("unable to start any build; either increase '--max-jobs' "
                            "or enable remote builds."
-                            "\nhttps://nixos.org/manual/nix/stable/advanced-topics/distributed-builds.html");
+                            "\nhttps://nixos.org/nix/manual/#chap-distributed-builds");
                else
                   throw Error("unable to start any build; remote machines may not have "
                            "all required system features."
-                            "\nhttps://nixos.org/manual/nix/stable/advanced-topics/distributed-builds.html");
+                            "\nhttps://nixos.org/nix/manual/#chap-distributed-builds");

            }
            assert(!awake.empty());
@@ -19,8 +19,3 @@ create table if not exists RealisationsRefs (
    foreign key (referrer) references Realisations(id) on delete cascade,
    foreign key (realisationReference) references Realisations(id) on delete restrict
 );
-
-- used by QueryRealisationReferences
-create index if not exists IndexRealisationsRefs on RealisationsRefs(referrer);
-- used by cascade deletion when ValidPaths is deleted
-create index if not exists IndexRealisationsRefsOnOutputPath on Realisations(outputPath);
@@ -4,6 +4,7 @@
 #include "store-api.hh"
 #include "path-with-outputs.hh"
 #include "finally.hh"
+#include "affinity.hh"
 #include "archive.hh"
 #include "derivations.hh"
 #include "args.hh"
@@ -69,7 +70,7 @@ struct TunnelLogger : public Logger

        StringSink buf;
        buf << STDERR_NEXT << (fs.s + "\n");
-        enqueueMsg(buf.s);
+        enqueueMsg(*buf.s);
    }

    void logEI(const ErrorInfo & ei) override
@@ -81,7 +82,7 @@ struct TunnelLogger : public Logger

        StringSink buf;
        buf << STDERR_NEXT << oss.str();
-        enqueueMsg(buf.s);
+        enqueueMsg(*buf.s);
    }

    /* startWork() means that we're starting an operation for which we
@@ -129,7 +130,7 @@ struct TunnelLogger : public Logger

        StringSink buf;
        buf << STDERR_START_ACTIVITY << act << lvl << type << s << fields << parent;
-        enqueueMsg(buf.s);
+        enqueueMsg(*buf.s);
    }

    void stopActivity(ActivityId act) override
@@ -137,7 +138,7 @@ struct TunnelLogger : public Logger
        if (GET_PROTOCOL_MINOR(clientVersion) < 20) return;
        StringSink buf;
        buf << STDERR_STOP_ACTIVITY << act;
-        enqueueMsg(buf.s);
+        enqueueMsg(*buf.s);
    }

    void result(ActivityId act, ResultType type, const Fields & fields) override
@@ -145,7 +146,7 @@ struct TunnelLogger : public Logger
        if (GET_PROTOCOL_MINOR(clientVersion) < 20) return;
        StringSink buf;
        buf << STDERR_RESULT << act << type << fields;
-        enqueueMsg(buf.s);
+        enqueueMsg(*buf.s);
    }
 };

@@ -430,30 +431,25 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
                hashAlgo = parseHashType(hashAlgoRaw);
            }

-            auto dumpSource = sinkToSource([&](Sink & saved) {
-                if (method == FileIngestionMethod::Recursive) {
-                    /* We parse the NAR dump through into `saved` unmodified,
-                       so why all this extra work? We still parse the NAR so
-                       that we aren't sending arbitrary data to `saved`
-                       unwittingly`, and we know when the NAR ends so we don't
-                       consume the rest of `from` and can't parse another
-                       command. (We don't trust `addToStoreFromDump` to not
-                       eagerly consume the entire stream it's given, past the
-                       length of the Nar. */
-                    TeeSource savedNARSource(from, saved);
-                    ParseSink sink; /* null sink; just parse the NAR */
-                    parseDump(sink, savedNARSource);
-                } else {
-                    /* Incrementally parse the NAR file, stripping the
-                       metadata, and streaming the sole file we expect into
-                       `saved`. */
-                    RetrieveRegularNARSink savedRegular { saved };
-                    parseDump(savedRegular, from);
-                    if (!savedRegular.regular) throw Error("regular file expected");
-                }
-            });
+            StringSink saved;
+            TeeSource savedNARSource(from, saved);
+            RetrieveRegularNARSink savedRegular { saved };
+
+            if (method == FileIngestionMethod::Recursive) {
+                /* Get the entire NAR dump from the client and save it to
+                  a string so that we can pass it to
+                  addToStoreFromDump(). */
+                ParseSink sink; /* null sink; just parse the NAR */
+                parseDump(sink, savedNARSource);
+            } else
+                parseDump(savedRegular, from);
+
            logger->startWork();
-            auto path = store->addToStoreFromDump(*dumpSource, baseName, method, hashAlgo);
+            if (!savedRegular.regular) throw Error("regular file expected");
+
+            // FIXME: try to stream directly from `from`.
+            StringSource dumpSource { *saved.s };
+            auto path = store->addToStoreFromDump(dumpSource, baseName, method, hashAlgo);
            logger->stopWork();

            to << store->printStorePath(path);
@@ -468,12 +464,10 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
            dontCheckSigs = false;

        logger->startWork();
-        {
-            FramedSource source(from);
-            store->addMultipleToStore(source,
-                RepairFlag{repair},
-                dontCheckSigs ? NoCheckSigs : CheckSigs);
-        }
+        FramedSource source(from);
+        store->addMultipleToStore(source,
+            RepairFlag{repair},
+            dontCheckSigs ? NoCheckSigs : CheckSigs);
        logger->stopWork();
        break;
    }
@@ -854,14 +848,14 @@ static void performOp(TunnelLogger * logger, ref<Store> store,

        else {
            std::unique_ptr<Source> source;
-            StringSink saved;
            if (GET_PROTOCOL_MINOR(clientVersion) >= 21)
                source = std::make_unique<TunnelSource>(from, to);
            else {
+                StringSink saved;
                TeeSource tee { from, saved };
                ParseSink ether;
                parseDump(ether, tee);
-                source = std::make_unique<StringSource>(saved.s);
+                source = std::make_unique<StringSource>(std::move(*saved.s));
            }

            logger->startWork();
@@ -922,22 +916,6 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
        break;
    }

-    case wopAddBuildLog: {
-        StorePath path{readString(from)};
-        logger->startWork();
-        if (!trusted)
-            throw Error("you are not privileged to add logs");
-        {
-            FramedSource source(from);
-            StringSink sink;
-            source.drainInto(sink);
-            store->addBuildLog(path, sink.s);
-        }
-        logger->stopWork();
-        to << 1;
-        break;
-    }
-
    default:
        throw Error("invalid operation %1%", op);
    }
@@ -973,12 +951,12 @@ void processConnection(

    Finally finally([&]() {
        _isInterrupted = false;
-        printMsgUsing(prevLogger, lvlDebug, "%d operations", opCount);
+        prevLogger->log(lvlDebug, fmt("%d operations", opCount));
    });

    if (GET_PROTOCOL_MINOR(clientVersion) >= 14 && readInt(from)) {
-        // Obsolete CPU affinity.
-        readInt(from);
+        auto affinity = readInt(from);
+        setAffinityTo(affinity);
    }

    readInt(from); // obsolete reserveSpace
@@ -1006,8 +984,6 @@ void processConnection(
                break;
            }

-            printMsgUsing(prevLogger, lvlDebug, "received daemon op %d", op);
-
            opCount++;

            try {
@@ -4,7 +4,6 @@
 #include "util.hh"
 #include "worker-protocol.hh"
 #include "fs-accessor.hh"
-#include <boost/container/small_vector.hpp>

 namespace nix {

@@ -273,9 +272,7 @@ Derivation parseDerivation(const Store & store, std::string && s, std::string_vi

 static void printString(string & res, std::string_view s)
 {
-    boost::container::small_vector<char, 64 * 1024> buffer;
-    buffer.reserve(s.size() * 2 + 2);
-    char * buf = buffer.data();
+    char buf[s.size() * 2 + 2];
    char * p = buf;
    *p++ = '"';
    for (auto c : s)
@@ -75,20 +75,20 @@ StorePaths Store::importPaths(Source & source, CheckSigsFlag checkSigs)

        auto references = worker_proto::read(*this, source, Phantom<StorePathSet> {});
        auto deriver = readString(source);
-        auto narHash = hashString(htSHA256, saved.s);
+        auto narHash = hashString(htSHA256, *saved.s);

        ValidPathInfo info { path, narHash };
        if (deriver != "")
            info.deriver = parseStorePath(deriver);
        info.references = references;
-        info.narSize = saved.s.size();
+        info.narSize = saved.s->size();

        // Ignore optional legacy signature.
        if (readInt(source) == 1)
            readString(source);

        // Can't use underlying source, which would have been exhausted
-        auto source = StringSource(saved.s);
+        auto source = StringSource { *saved.s };
        addToStore(info, source, NoRepair, checkSigs);

        res.push_back(info.path);
@@ -106,7 +106,7 @@ struct curlFileTransfer : public FileTransfer
                        this->request.dataCallback(data);
                    }
                } else
-                    this->result.data.append(data);
+                    this->result.data->append(data);
              })
        {
            if (!request.expectedETag.empty())
@@ -128,7 +128,7 @@ struct curlFileTransfer : public FileTransfer
            if (requestHeaders) curl_slist_free_all(requestHeaders);
            try {
                if (!done)
-                    fail(FileTransferError(Interrupted, {}, "download of '%s' was interrupted", request.uri));
+                    fail(FileTransferError(Interrupted, nullptr, "download of '%s' was interrupted", request.uri));
            } catch (...) {
                ignoreException();
            }
@@ -195,7 +195,7 @@ struct curlFileTransfer : public FileTransfer
            std::smatch match;
            if (std::regex_match(line, match, statusLine)) {
                result.etag = "";
-                result.data.clear();
+                result.data = std::make_shared<std::string>();
                result.bodySize = 0;
                statusMsg = trim(match[1]);
                acceptRanges = false;
@@ -340,7 +340,7 @@ struct curlFileTransfer : public FileTransfer
            if (writtenToSink)
                curl_easy_setopt(req, CURLOPT_RESUME_FROM_LARGE, writtenToSink);

-            result.data.clear();
+            result.data = std::make_shared<std::string>();
            result.bodySize = 0;
        }

@@ -434,21 +434,21 @@ struct curlFileTransfer : public FileTransfer

                attempt++;

-                std::optional<std::string> response;
+                std::shared_ptr<std::string> response;
                if (errorSink)
-                    response = std::move(errorSink->s);
+                    response = errorSink->s;
                auto exc =
                    code == CURLE_ABORTED_BY_CALLBACK && _isInterrupted
-                    ? FileTransferError(Interrupted, std::move(response), "%s of '%s' was interrupted", request.verb(), request.uri)
+                    ? FileTransferError(Interrupted, response, "%s of '%s' was interrupted", request.verb(), request.uri)
                    : httpStatus != 0
                    ? FileTransferError(err,
-                        std::move(response),
+                        response,
                        fmt("unable to %s '%s': HTTP error %d ('%s')",
                            request.verb(), request.uri, httpStatus, statusMsg)
                        + (code == CURLE_OK ? "" : fmt(" (curl error: %s)", curl_easy_strerror(code)))
                        )
                    : FileTransferError(err,
-                        std::move(response),
+                        response,
                        fmt("unable to %s '%s': %s (%d)",
                            request.verb(), request.uri, curl_easy_strerror(code), code));

@@ -544,7 +544,13 @@ struct curlFileTransfer : public FileTransfer
            stopWorkerThread();
        });

-        unshareFilesystem();
+#ifdef __linux__
+        /* Cause this thread to not share any FS attributes with the main thread,
+           because this causes setns() in restoreMountNamespace() to fail.
+           Ideally, this would happen in the std::thread() constructor. */
+        if (unshare(CLONE_FS) != 0)
+            throw SysError("unsharing filesystem state in download thread");
+#endif

        std::map<CURL *, std::shared_ptr<TransferItem>> items;

@@ -704,8 +710,8 @@ struct curlFileTransfer : public FileTransfer
                auto s3Res = s3Helper.getObject(bucketName, key);
                FileTransferResult res;
                if (!s3Res.data)
-                    throw FileTransferError(NotFound, {}, "S3 object '%s' does not exist", request.uri);
-                res.data = std::move(*s3Res.data);
+                    throw FileTransferError(NotFound, nullptr, "S3 object '%s' does not exist", request.uri);
+                res.data = s3Res.data;
                callback(std::move(res));
 #else
                throw nix::Error("cannot download '%s' because Nix is not built with S3 support", request.uri);
@@ -859,7 +865,7 @@ void FileTransfer::download(FileTransferRequest && request, Sink & sink)
 }

 template<typename... Args>
-FileTransferError::FileTransferError(FileTransfer::Error error, std::optional<std::string> response, const Args & ... args)
+FileTransferError::FileTransferError(FileTransfer::Error error, std::shared_ptr<string> response, const Args & ... args)
    : Error(args...), error(error), response(response)
 {
    const auto hf = hintfmt(args...);
@@ -59,7 +59,7 @@ struct FileTransferRequest
    unsigned int baseRetryTimeMs = 250;
    ActivityId parentAct;
    bool decompress = true;
-    std::optional<std::string> data;
+    std::shared_ptr<std::string> data;
    std::string mimeType;
    std::function<void(std::string_view data)> dataCallback;

@@ -77,7 +77,7 @@ struct FileTransferResult
    bool cached = false;
    std::string etag;
    std::string effectiveUri;
-    std::string data;
+    std::shared_ptr<std::string> data;
    uint64_t bodySize = 0;
 };

@@ -119,10 +119,10 @@ class FileTransferError : public Error
 {
 public:
    FileTransfer::Error error;
-    std::optional<string> response; // intentionally optional
+    std::shared_ptr<string> response; // intentionally optional

    template<typename... Args>
-    FileTransferError(FileTransfer::Error error, std::optional<string> response, const Args & ... args);
+    FileTransferError(FileTransfer::Error error, std::shared_ptr<string> response, const Args & ... args);

    virtual const char* sname() const override { return "FileTransferError"; }
 };
@@ -126,17 +126,7 @@ void LocalStore::addTempRoot(const StorePath & path)
            auto socketPath = stateDir.get() + gcSocketPath;
            debug("connecting to '%s'", socketPath);
            state->fdRootsSocket = createUnixDomainSocket();
-            try {
-                nix::connect(state->fdRootsSocket.get(), socketPath);
-            } catch (SysError & e) {
-                /* The garbage collector may have exited, so we need to
-                   restart. */
-                if (e.errNo == ECONNREFUSED) {
-                    debug("GC socket connection refused");
-                    state->fdRootsSocket.close();
-                    goto restart;
-                }
-            }
+            nix::connect(state->fdRootsSocket.get(), socketPath);
        }

        try {
@@ -533,8 +523,6 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                AutoCloseFD fdClient = accept(fdServer.get(), nullptr, nullptr);
                if (!fdClient) continue;

-                debug("GC roots server accepted new client");
-
                /* Process the connection in a separate thread. */
                auto fdClient_ = fdClient.get();
                std::thread clientThread([&, fdClient = std::move(fdClient)]() {
@@ -547,12 +535,6 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                        }
                    });

-                    /* On macOS, accepted sockets inherit the
-                       non-blocking flag from the server socket, so
-                       explicitly make it blocking. */
-                    if (fcntl(fdServer.get(), F_SETFL, fcntl(fdServer.get(), F_GETFL) & ~O_NONBLOCK) == -1)
-                        abort();
-
                    while (true) {
                        try {
                            auto path = readLine(fdClient.get());
@@ -577,10 +559,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                            } else
                                printError("received garbage instead of a root from client");
                            writeFull(fdClient.get(), "1", false);
-                        } catch (Error & e) {
-                            debug("reading GC root from client: %s", e.msg());
-                            break;
-                        }
+                        } catch (Error &) { break; }
                    }
                });

@@ -21,7 +21,7 @@ struct MaxBuildJobsSetting : public BaseSetting<unsigned int>
        const std::string & name,
        const std::string & description,
        const std::set<std::string> & aliases = {})
-        : BaseSetting<unsigned int>(def, true, name, description, aliases)
+        : BaseSetting<unsigned int>(def, name, description, aliases)
    {
        options->addSetting(this);
    }
@@ -38,7 +38,7 @@ struct PluginFilesSetting : public BaseSetting<Paths>
        const std::string & name,
        const std::string & description,
        const std::set<std::string> & aliases = {})
-        : BaseSetting<Paths>(def, true, name, description, aliases)
+        : BaseSetting<Paths>(def, name, description, aliases)
    {
        options->addSetting(this);
    }
@@ -130,9 +130,7 @@ public:
        {"build-max-jobs"}};

    Setting<unsigned int> buildCores{
-        this,
-        getDefaultCores(),
-        "cores",
+        this, getDefaultCores(), "cores",
        R"(
          Sets the value of the `NIX_BUILD_CORES` environment variable in the
          invocation of builders. Builders can use this variable at their
@@ -143,7 +141,7 @@ public:
          command line switch and defaults to `1`. The value `0` means that
          the builder should use all available CPU cores in the system.
        )",
-        {"build-cores"}, false};
+        {"build-cores"}};

    /* Read-only mode.  Don't copy stuff to the store, don't change
       the database. */
@@ -585,11 +583,10 @@ public:
          platform and generate incompatible code, so you may wish to
          cross-check the results of using this option against proper
          natively-built versions of your derivations.
-        )", {}, false};
+        )"};

    Setting<StringSet> systemFeatures{
-        this,
-        getDefaultSystemFeatures(),
+        this, getDefaultSystemFeatures(),
        "system-features",
        R"(
          A set of system “features” supported by this machine, e.g. `kvm`.
@@ -605,7 +602,7 @@ public:
          This setting by default includes `kvm` if `/dev/kvm` is accessible,
          and the pseudo-features `nixos-test`, `benchmark` and `big-parallel`
          that are used in Nixpkgs to route builds to specific machines.
-        )", {}, false};
+        )"};

    Setting<Strings> substituters{
        this,
@@ -800,15 +797,6 @@ public:
          may be useful in certain scenarios (e.g. to spin up containers or
          set up userspace network interfaces in tests).
        )"};
-
-    Setting<StringSet> ignoredAcls{
-        this, {"security.selinux", "system.nfs4_acl"}, "ignored-acls",
-        R"(
-          A list of ACLs that should be ignored, normally Nix attempts to
-          remove all ACLs from files and directories in the Nix store, but
-          some ACLs like `security.selinux` or `system.nfs4_acl` can't be
-          removed even by root. Therefore it's best to just ignore them.
-        )"};
 #endif

    Setting<Strings> hashedMirrors{
@@ -966,13 +954,6 @@ public:

    Setting<bool> acceptFlakeConfig{this, false, "accept-flake-config",
        "Whether to accept nix configuration from a flake without prompting."};
-
-    Setting<std::string> commitLockFileSummary{
-        this, "", "commit-lockfile-summary",
-        R"(
-          The commit summary to use when commiting changed flake lock files. If
-          empty, the summary is generated based on the action performed.
-        )"};
 };


@@ -126,7 +126,7 @@ protected:
        const std::string & mimeType) override
    {
        auto req = makeRequest(path);
-        req.data = StreamToSourceAdapter(istream).drain();
+        req.data = std::make_shared<string>(StreamToSourceAdapter(istream).drain());
        req.mimeType = mimeType;
        try {
            getFileTransfer()->upload(req);
@@ -159,7 +159,7 @@ protected:
    }

    void getFile(const std::string & path,
-        Callback<std::optional<std::string>> callback) noexcept override
+        Callback<std::shared_ptr<std::string>> callback) noexcept override
    {
        checkEnabled();

@@ -170,10 +170,10 @@ protected:
        getFileTransfer()->enqueueFileTransfer(request,
            {[callbackPtr, this](std::future<FileTransferResult> result) {
                try {
-                    (*callbackPtr)(std::move(result.get().data));
+                    (*callbackPtr)(result.get().data);
                } catch (FileTransferError & e) {
                    if (e.error == FileTransfer::NotFound || e.error == FileTransfer::Forbidden)
-                        return (*callbackPtr)({});
+                        return (*callbackPtr)(std::shared_ptr<std::string>());
                    maybeDisable();
                    callbackPtr->rethrow();
                } catch (...) {
@@ -94,7 +94,7 @@ struct LegacySSHStore : public virtual LegacySSHStoreConfig, public virtual Stor
                conn->sshConn->in.close();
                auto msg = conn->from.drain();
                throw Error("'nix-store --serve' protocol mismatch from '%s', got '%s'",
-                    host, chomp(saved.s + msg));
+                    host, chomp(*saved.s + msg));
            }
            conn->remoteVersion = readInt(conn->from);
            if (GET_PROTOCOL_MAJOR(conn->remoteVersion) != 0x200)
@@ -96,7 +96,6 @@ void LocalBinaryCacheStore::init()
    createDirs(binaryCacheDir + "/" + realisationsPrefix);
    if (writeDebugInfo)
        createDirs(binaryCacheDir + "/debuginfo");
-    createDirs(binaryCacheDir + "/log");
    BinaryCacheStore::init();
 }

@@ -87,32 +87,34 @@ void LocalFSStore::narFromPath(const StorePath & path, Sink & sink)

 const string LocalFSStore::drvsLogDir = "drvs";

-std::optional<std::string> LocalFSStore::getBuildLog(const StorePath & path_)
+
+
+std::shared_ptr<std::string> LocalFSStore::getBuildLog(const StorePath & path_)
 {
    auto path = path_;

    if (!path.isDerivation()) {
        try {
            auto info = queryPathInfo(path);
-            if (!info->deriver) return std::nullopt;
+            if (!info->deriver) return nullptr;
            path = *info->deriver;
        } catch (InvalidPath &) {
-            return std::nullopt;
+            return nullptr;
        }
    }

-    auto baseName = path.to_string();
+    auto baseName = std::string(baseNameOf(printStorePath(path)));

    for (int j = 0; j < 2; j++) {

        Path logPath =
            j == 0
-            ? fmt("%s/%s/%s/%s", logDir, drvsLogDir, baseName.substr(0, 2), baseName.substr(2))
+            ? fmt("%s/%s/%s/%s", logDir, drvsLogDir, string(baseName, 0, 2), string(baseName, 2))
            : fmt("%s/%s/%s", logDir, drvsLogDir, baseName);
        Path logBz2Path = logPath + ".bz2";

        if (pathExists(logPath))
-            return readFile(logPath);
+            return std::make_shared<std::string>(readFile(logPath));

        else if (pathExists(logBz2Path)) {
            try {
@@ -122,7 +124,7 @@ std::optional<std::string> LocalFSStore::getBuildLog(const StorePath & path_)

    }

-    return std::nullopt;
+    return nullptr;
 }

 }
@@ -45,8 +45,7 @@ public:
        return getRealStoreDir() + "/" + std::string(storePath, storeDir.size() + 1);
    }

-    std::optional<std::string> getBuildLog(const StorePath & path) override;
-
+    std::shared_ptr<std::string> getBuildLog(const StorePath & path) override;
 };

 }
@@ -8,8 +8,6 @@
 #include "references.hh"
 #include "callback.hh"
 #include "topo-sort.hh"
-#include "finally.hh"
-#include "compression.hh"

 #include <iostream>
 #include <algorithm>
@@ -81,7 +79,7 @@ int getSchema(Path schemaPath)

 void migrateCASchema(SQLite& db, Path schemaPath, AutoCloseFD& lockFd)
 {
-    const int nixCASchemaVersion = 3;
+    const int nixCASchemaVersion = 2;
    int curCASchema = getSchema(schemaPath);
    if (curCASchema != nixCASchemaVersion) {
        if (curCASchema > nixCASchemaVersion) {
@@ -132,17 +130,6 @@ void migrateCASchema(SQLite& db, Path schemaPath, AutoCloseFD& lockFd)
            txn.commit();
        }

-        if (curCASchema < 3) {
-            SQLiteTxn txn(db);
-            // Apply new indices added in this schema update.
-            db.exec(R"(
-                -- used by QueryRealisationReferences
-                create index if not exists IndexRealisationsRefs on RealisationsRefs(referrer);
-                -- used by cascade deletion when ValidPaths is deleted
-                create index if not exists IndexRealisationsRefsOnOutputPath on Realisations(outputPath);
-            )");
-            txn.commit();
-        }
        writeFile(schemaPath, fmt("%d", nixCASchemaVersion));
        lockFile(lockFd.get(), ltRead, true);
    }
@@ -602,7 +589,9 @@ static void canonicalisePathMetaData_(const Path & path, uid_t fromUid, InodesSe
            throw SysError("querying extended attributes of '%s'", path);

        for (auto & eaName: tokenizeString<Strings>(std::string(eaBuf.data(), eaSize), std::string("\000", 1))) {
-            if (settings.ignoredAcls.get().count(eaName)) continue;
+            /* Ignore SELinux security labels since these cannot be
+               removed even by root. */
+            if (eaName == "security.selinux") continue;
            if (lremovexattr(path.c_str(), eaName.c_str()) == -1)
                throw SysError("removing extended attribute '%s' from '%s'", eaName, path);
        }
@@ -1308,7 +1297,7 @@ void LocalStore::addToStore(const ValidPathInfo & info, Source & source,

            canonicalisePathMetaData(realPath, -1);

-            optimisePath(realPath, repair); // FIXME: combine with hashPath()
+            optimisePath(realPath); // FIXME: combine with hashPath()

            registerValidPath(info);
        }
@@ -1344,15 +1333,13 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, const string & name,
        auto want = std::min(chunkSize, settings.narBufferSize - oldSize);
        dump.resize(oldSize + want);
        auto got = 0;
-        Finally cleanup([&]() {
-            dump.resize(oldSize + got);
-        });
        try {
            got = source.read(dump.data() + oldSize, want);
        } catch (EndOfFile &) {
            inMemory = true;
            break;
        }
+        dump.resize(oldSize + got);
    }

    std::unique_ptr<AutoDelete> delTempDir;
@@ -1420,7 +1407,7 @@ StorePath LocalStore::addToStoreFromDump(Source & source0, const string & name,

            canonicalisePathMetaData(realPath, -1); // FIXME: merge into restorePath

-            optimisePath(realPath, repair);
+            optimisePath(realPath);

            ValidPathInfo info { dstPath, narHash.first };
            info.narSize = narHash.second;
@@ -1462,12 +1449,12 @@ StorePath LocalStore::addTextToStore(const string & name, const string & s,

            StringSink sink;
            dumpString(s, sink);
-            auto narHash = hashString(htSHA256, sink.s);
+            auto narHash = hashString(htSHA256, *sink.s);

-            optimisePath(realPath, repair);
+            optimisePath(realPath);

            ValidPathInfo info { dstPath, narHash };
-            info.narSize = sink.s.size();
+            info.narSize = sink.s->size();
            info.references = references;
            info.ca = TextHash { .hash = hash };
            registerValidPath(info);
@@ -1899,24 +1886,4 @@ FixedOutputHash LocalStore::hashCAPath(
    };
 }

-void LocalStore::addBuildLog(const StorePath & drvPath, std::string_view log)
-{
-    assert(drvPath.isDerivation());
-
-    auto baseName = drvPath.to_string();
-
-    auto logPath = fmt("%s/%s/%s/%s.bz2", logDir, drvsLogDir, baseName.substr(0, 2), baseName.substr(2));
-
-    if (pathExists(logPath)) return;
-
-    createDirs(dirOf(logPath));
-
-    auto tmpFile = fmt("%s.tmp.%d", logPath, getpid());
-
-    writeFile(tmpFile, compress("bzip2", log));
-
-    if (rename(tmpFile.c_str(), logPath.c_str()) != 0)
-        throw SysError("renaming '%1%' to '%2%'", tmpFile, logPath);
-}
-
 }  // namespace nix
@@ -172,9 +172,8 @@ public:

    void optimiseStore() override;

-    /* Optimise a single store path. Optionally, test the encountered
-       symlinks for corruption. */
-    void optimisePath(const Path & path, RepairFlag repair);
+    /* Optimise a single store path. */
+    void optimisePath(const Path & path);

    bool verifyStore(bool checkContents, RepairFlag repair) override;

@@ -254,7 +253,7 @@ private:

    InodeHash loadInodeHash();
    Strings readDirectoryIgnoringInodes(const Path & path, const InodeHash & inodeHash);
-    void optimisePath_(Activity * act, OptimiseStats & stats, const Path & path, InodeHash & inodeHash, RepairFlag repair);
+    void optimisePath_(Activity * act, OptimiseStats & stats, const Path & path, InodeHash & inodeHash);

    // Internal versions that are not wrapped in retry_sqlite.
    bool isValidPath_(State & state, const StorePath & path);
@@ -280,8 +279,6 @@ private:
        const std::string_view pathHash
    );

-    void addBuildLog(const StorePath & drvPath, std::string_view log) override;
-
    friend struct LocalDerivationGoal;
    friend struct PathSubstitutionGoal;
    friend struct SubstitutionGoal;
@@ -7,7 +7,6 @@
 #include "topo-sort.hh"
 #include "callback.hh"
 #include "closure.hh"
-#include "filetransfer.hh"

 namespace nix {

@@ -101,8 +100,7 @@ void Store::queryMissing(const std::vector<DerivedPath> & targets,

    downloadSize_ = narSize_ = 0;

-    // FIXME: make async.
-    ThreadPool pool(fileTransferSettings.httpConnections);
+    ThreadPool pool;

    struct State
    {
@@ -42,7 +42,7 @@ DrvName::~DrvName()
 { }


-bool DrvName::matches(const DrvName & n)
+bool DrvName::matches(DrvName & n)
 {
    if (name != "*") {
        if (!regex) {
@@ -19,7 +19,7 @@ struct DrvName
    DrvName(std::string_view s);
    ~DrvName();

-    bool matches(const DrvName & n);
+    bool matches(DrvName & n);

 private:
    std::unique_ptr<Regex> regex;
@@ -28,7 +28,7 @@ struct NarMember

 struct NarAccessor : public FSAccessor
 {
-    std::optional<const std::string> nar;
+    std::shared_ptr<const std::string> nar;

    GetNarBytes getNarBytes;

@@ -104,7 +104,7 @@ struct NarAccessor : public FSAccessor
        }
    };

-    NarAccessor(std::string && _nar) : nar(_nar)
+    NarAccessor(ref<const std::string> nar) : nar(nar)
    {
        StringSource source(*nar);
        NarIndexer indexer(*this, source);
@@ -224,9 +224,9 @@ struct NarAccessor : public FSAccessor
    }
 };

-ref<FSAccessor> makeNarAccessor(std::string && nar)
+ref<FSAccessor> makeNarAccessor(ref<const std::string> nar)
 {
-    return make_ref<NarAccessor>(std::move(nar));
+    return make_ref<NarAccessor>(nar);
 }

 ref<FSAccessor> makeNarAccessor(Source & source)
@@ -10,7 +10,7 @@ struct Source;

 /* Return an object that provides access to the contents of a NAR
   file. */
-ref<FSAccessor> makeNarAccessor(std::string && nar);
+ref<FSAccessor> makeNarAccessor(ref<const std::string> nar);

 ref<FSAccessor> makeNarAccessor(Source & source);

@@ -88,7 +88,7 @@ Strings LocalStore::readDirectoryIgnoringInodes(const Path & path, const InodeHa


 void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
-    const Path & path, InodeHash & inodeHash, RepairFlag repair)
+    const Path & path, InodeHash & inodeHash)
 {
    checkInterrupt();

@@ -110,7 +110,7 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
    if (S_ISDIR(st.st_mode)) {
        Strings names = readDirectoryIgnoringInodes(path, inodeHash);
        for (auto & i : names)
-            optimisePath_(act, stats, path + "/" + i, inodeHash, repair);
+            optimisePath_(act, stats, path + "/" + i, inodeHash);
        return;
    }

@@ -151,20 +151,7 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
    /* Check if this is a known hash. */
    Path linkPath = linksDir + "/" + hash.to_string(Base32, false);

-    /* Maybe delete the link, if it has been corrupted. */
-    if (pathExists(linkPath)) {
-        auto stLink = lstat(linkPath);
-        if (st.st_size != stLink.st_size
-            || (repair && hash != hashPath(htSHA256, linkPath).first))
-        {
-            // XXX: Consider overwriting linkPath with our valid version.
-            warn("removing corrupted link '%s'", linkPath);
-            warn("There may be more corrupted paths."
-                 "\nYou should run `nix-store --verify --check-contents --repair` to fix them all");
-            unlink(linkPath.c_str());
-        }
-    }
-
+ retry:
    if (!pathExists(linkPath)) {
        /* Nope, create a hard link in the links directory. */
        if (link(path.c_str(), linkPath.c_str()) == 0) {
@@ -200,6 +187,12 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
        return;
    }

+    if (st.st_size != stLink.st_size) {
+        warn("removing corrupted link '%s'", linkPath);
+        unlink(linkPath.c_str());
+        goto retry;
+    }
+
    printMsg(lvlTalkative, format("linking '%1%' to '%2%'") % path % linkPath);

    /* Make the containing directory writable, but only if it's not
@@ -267,7 +260,7 @@ void LocalStore::optimiseStore(OptimiseStats & stats)
        if (!isValidPath(i)) continue; /* path was GC'ed, probably */
        {
            Activity act(*logger, lvlTalkative, actUnknown, fmt("optimising path '%s'", printStorePath(i)));
-            optimisePath_(&act, stats, realStoreDir + "/" + std::string(i.to_string()), inodeHash, NoRepair);
+            optimisePath_(&act, stats, realStoreDir + "/" + std::string(i.to_string()), inodeHash);
        }
        done++;
        act.progress(done, paths.size());
@@ -285,12 +278,12 @@ void LocalStore::optimiseStore()
        stats.filesLinked);
 }

-void LocalStore::optimisePath(const Path & path, RepairFlag repair)
+void LocalStore::optimisePath(const Path & path)
 {
    OptimiseStats stats;
    InodeHash inodeHash;

-    if (settings.autoOptimiseStore) optimisePath_(nullptr, stats, path, inodeHash, repair);
+    if (settings.autoOptimiseStore) optimisePath_(nullptr, stats, path, inodeHash);
 }


@@ -78,7 +78,7 @@ Realisation Realisation::fromJSON(
        auto fieldIterator = json.find(fieldName);
        if (fieldIterator == json.end())
            return std::nullopt;
-        return {*fieldIterator};
+        return *fieldIterator;
    };
    auto getField = [&](std::string fieldName) -> std::string {
        if (auto field = getOptionalField(fieldName))
@@ -22,18 +22,9 @@ Path RemoteFSAccessor::makeCacheFile(std::string_view hashPart, const std::strin
    return fmt("%s/%s.%s", cacheDir, hashPart, ext);
 }

-ref<FSAccessor> RemoteFSAccessor::addToCache(std::string_view hashPart, std::string && nar)
+void RemoteFSAccessor::addToCache(std::string_view hashPart, const std::string & nar,
+    ref<FSAccessor> narAccessor)
 {
-    if (cacheDir != "") {
-        try {
-            /* FIXME: do this asynchronously. */
-            writeFile(makeCacheFile(hashPart, "nar"), nar);
-        } catch (...) {
-            ignoreException();
-        }
-    }
-
-    auto narAccessor = makeNarAccessor(std::move(nar));
    nars.emplace(hashPart, narAccessor);

    if (cacheDir != "") {
@@ -42,12 +33,14 @@ ref<FSAccessor> RemoteFSAccessor::addToCache(std::string_view hashPart, std::str
            JSONPlaceholder jsonRoot(str);
            listNar(jsonRoot, narAccessor, "", true);
            writeFile(makeCacheFile(hashPart, "ls"), str.str());
+
+            /* FIXME: do this asynchronously. */
+            writeFile(makeCacheFile(hashPart, "nar"), nar);
+
        } catch (...) {
            ignoreException();
        }
    }
-
-    return narAccessor;
 }

 std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path & path_, bool requireValidPath)
@@ -62,6 +55,7 @@ std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path & path_, boo
    auto i = nars.find(std::string(storePath.hashPart()));
    if (i != nars.end()) return {i->second, restPath};

+    StringSink sink;
    std::string listing;
    Path cacheFile;

@@ -92,15 +86,19 @@ std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path & path_, boo
        } catch (SysError &) { }

        try {
-            auto narAccessor = makeNarAccessor(nix::readFile(cacheFile));
+            *sink.s = nix::readFile(cacheFile);
+
+            auto narAccessor = makeNarAccessor(sink.s);
            nars.emplace(storePath.hashPart(), narAccessor);
            return {narAccessor, restPath};
+
        } catch (SysError &) { }
    }

-    StringSink sink;
    store->narFromPath(storePath, sink);
-    return {addToCache(storePath.hashPart(), std::move(sink.s)), restPath};
+    auto narAccessor = makeNarAccessor(sink.s);
+    addToCache(storePath.hashPart(), *sink.s, narAccessor);
+    return {narAccessor, restPath};
 }

 FSAccessor::Stat RemoteFSAccessor::stat(const Path & path)
@@ -20,7 +20,8 @@ class RemoteFSAccessor : public FSAccessor

    Path makeCacheFile(std::string_view hashPart, const std::string & ext);

-    ref<FSAccessor> addToCache(std::string_view hashPart, std::string && nar);
+    void addToCache(std::string_view hashPart, const std::string & nar,
+        ref<FSAccessor> narAccessor);

 public:
Author	SHA1	Message	Date
regnat	cc711c6956	Add aliases for the old flake commands Requires reworking a bit the existing alias mechanism to allow aliases to be composite commands themselves	2021-11-25 21:42:55 +01:00
regnat	401b09b7fe	Move `nix flake {new,init}` at toplevel Fix #4502	2021-11-25 21:42:55 +01:00
@@ -1 +1 @@
 .6.1
 .5