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Author SHA1 Message Date
John Ericson
a7c841f704 Make store setting and store flags use StoreReference 2024-05-22 18:06:07 -04:00
976 changed files with 21906 additions and 24129 deletions

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@@ -31,3 +31,4 @@ AlwaysBreakBeforeMultilineStrings: true
IndentPPDirectives: AfterHash
PPIndentWidth: 2
BinPackArguments: false
BinPackParameters: false

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@@ -4,20 +4,20 @@
# Top-most EditorConfig file
root = true
# Unix-style newlines with a newline ending every file, UTF-8 charset
# Unix-style newlines with a newline ending every file, utf-8 charset
[*]
end_of_line = lf
insert_final_newline = true
trim_trailing_whitespace = true
charset = utf-8
# Match Nix files, set indent to spaces with width of two
# Match nix files, set indent to spaces with width of two
[*.nix]
indent_style = space
indent_size = 2
# Match C++/C/shell/Perl, set indent to spaces with width of four
[*.{hpp,cc,hh,c,h,sh,pl,xs}]
# Match c++/shell/perl, set indent to spaces with width of four
[*.{hpp,cc,hh,sh,pl,xs}]
indent_style = space
indent_size = 4

13
.github/CODEOWNERS vendored
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@@ -11,16 +11,7 @@
.github/CODEOWNERS @edolstra
# Documentation of built-in functions
src/libexpr/primops.cc @roberth @fricklerhandwerk
# Documentation of settings
src/libexpr/eval-settings.hh @fricklerhandwerk
src/libstore/globals.hh @fricklerhandwerk
# Documentation
doc/manual @fricklerhandwerk
maintainers/*.md @fricklerhandwerk
src/**/*.md @fricklerhandwerk
src/libexpr/primops.cc @roberth
# Libstore layer
/src/libstore @ericson2314
/src/libstore @thufschmitt @ericson2314

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@@ -21,7 +21,7 @@ jobs:
fetch-depth: 0
- name: Create backport PRs
# should be kept in sync with `version`
uses: zeebe-io/backport-action@v3.0.2
uses: zeebe-io/backport-action@v2.5.0
with:
# Config README: https://github.com/zeebe-io/backport-action#backport-action
github_token: ${{ secrets.GITHUB_TOKEN }}

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@@ -31,34 +31,8 @@ jobs:
name: '${{ env.CACHIX_NAME }}'
signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
- if: matrix.os == 'ubuntu-latest'
run: |
free -h
swapon --show
swap=$(swapon --show --noheadings | head -n 1 | awk '{print $1}')
echo "Found swap: $swap"
sudo swapoff $swap
# resize it (fallocate)
sudo fallocate -l 10G $swap
sudo mkswap $swap
sudo swapon $swap
free -h
(
while sleep 60; do
free -h
done
) &
- run: nix --experimental-features 'nix-command flakes' flake check -L
# Steps to test CI automation in your own fork.
# Cachix:
# 1. Sign-up for https://www.cachix.org/
# 2. Create a cache for $githubuser-nix-install-tests
# 3. Create a cachix auth token and save it in https://github.com/$githubuser/nix/settings/secrets/actions in "Repository secrets" as CACHIX_AUTH_TOKEN
# Dockerhub:
# 1. Sign-up for https://hub.docker.com/
# 2. Store your dockerhub username as DOCKERHUB_USERNAME in "Repository secrets" of your fork repository settings (https://github.com/$githubuser/nix/settings/secrets/actions)
# 3. Create an access token in https://hub.docker.com/settings/security and store it as DOCKERHUB_TOKEN in "Repository secrets" of your fork
check_secrets:
permissions:
contents: none
@@ -96,7 +70,6 @@ jobs:
name: '${{ env.CACHIX_NAME }}'
signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
cachixArgs: '-v'
- id: prepare-installer
run: scripts/prepare-installer-for-github-actions
@@ -154,8 +127,8 @@ jobs:
authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
- run: nix --experimental-features 'nix-command flakes' build .#dockerImage -L
- run: docker load -i ./result/image.tar.gz
- run: docker tag nix:$NIX_VERSION ${{ secrets.DOCKERHUB_USERNAME }}/nix:$NIX_VERSION
- run: docker tag nix:$NIX_VERSION ${{ secrets.DOCKERHUB_USERNAME }}/nix:master
- run: docker tag nix:$NIX_VERSION nixos/nix:$NIX_VERSION
- run: docker tag nix:$NIX_VERSION nixos/nix:master
# We'll deploy the newly built image to both Docker Hub and Github Container Registry.
#
# Push to Docker Hub first
@@ -164,8 +137,8 @@ jobs:
with:
username: ${{ secrets.DOCKERHUB_USERNAME }}
password: ${{ secrets.DOCKERHUB_TOKEN }}
- run: docker push ${{ secrets.DOCKERHUB_USERNAME }}/nix:$NIX_VERSION
- run: docker push ${{ secrets.DOCKERHUB_USERNAME }}/nix:master
- run: docker push nixos/nix:$NIX_VERSION
- run: docker push nixos/nix:master
# Push to GitHub Container Registry as well
- name: Login to GitHub Container Registry
uses: docker/login-action@v3
@@ -193,38 +166,4 @@ jobs:
- uses: actions/checkout@v4
- uses: DeterminateSystems/nix-installer-action@main
- uses: DeterminateSystems/magic-nix-cache-action@main
- run: nix build -L .#hydraJobs.tests.githubFlakes .#hydraJobs.tests.tarballFlakes .#hydraJobs.tests.functional_user
meson_build:
strategy:
fail-fast: false
matrix:
os: [ubuntu-latest, macos-latest]
runs-on: ${{ matrix.os }}
steps:
- uses: actions/checkout@v4
- uses: DeterminateSystems/nix-installer-action@main
- uses: DeterminateSystems/magic-nix-cache-action@main
# Only meson packages that don't have a tests.run derivation.
# Those that have it are already built and tested as part of nix flake check.
- run: nix build -L .#hydraJobs.build.{nix-cmd,nix-main}.$(nix-instantiate --eval --expr builtins.currentSystem | sed -e 's/"//g')
flake_regressions:
needs: vm_tests
runs-on: ubuntu-22.04
steps:
- name: Checkout nix
uses: actions/checkout@v4
- name: Checkout flake-regressions
uses: actions/checkout@v4
with:
repository: NixOS/flake-regressions
path: flake-regressions
- name: Checkout flake-regressions-data
uses: actions/checkout@v4
with:
repository: NixOS/flake-regressions-data
path: flake-regressions/tests
- uses: DeterminateSystems/nix-installer-action@main
- uses: DeterminateSystems/magic-nix-cache-action@main
- run: nix build --out-link ./new-nix && PATH=$(pwd)/new-nix/bin:$PATH scripts/flake-regressions.sh
- run: nix build -L .#hydraJobs.tests.githubFlakes .#hydraJobs.tests.tarballFlakes

20
.github/workflows/hydra_status.yml vendored Normal file
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@@ -0,0 +1,20 @@
name: Hydra status
permissions: read-all
on:
schedule:
- cron: "12,42 * * * *"
workflow_dispatch:
jobs:
check_hydra_status:
name: Check Hydra status
if: github.repository_owner == 'NixOS'
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
with:
fetch-depth: 0
- run: bash scripts/check-hydra-status.sh

7
.gitignore vendored
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@@ -11,8 +11,6 @@ perl/Makefile.config
/svn-revision
/libtool
/config/config.*
# Default meson build dir
/build
# /doc/manual/
/doc/manual/*.1
@@ -54,9 +52,6 @@ perl/Makefile.config
# /src/libfetchers
/tests/unit/libfetchers/libnixfetchers-tests
# /src/libflake
/tests/unit/libflake/libnixflake-tests
# /src/libstore/
*.gen.*
/src/libstore/tests
@@ -97,7 +92,7 @@ perl/Makefile.config
# /tests/functional/
/tests/functional/test-tmp
/tests/functional/common/subst-vars.sh
/tests/functional/common/vars-and-functions.sh
/tests/functional/result*
/tests/functional/restricted-innocent
/tests/functional/shell

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@@ -1,4 +0,0 @@
external-sources=true
source-path=SCRIPTDIR
# Hack for scripts in e.g. tests/functional/ca
source-path=SCRIPTDIR/..

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@@ -1 +1 @@
2.24.0
2.23.0

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@@ -41,9 +41,9 @@ Check out the [security policy](https://github.com/NixOS/nix/security/policy).
There are many open pull requests that might already do what you intend to work on.
You can use [labels](https://github.com/NixOS/nix/labels) to filter for relevant topics.
3. Check the [Nix reference manual](https://nix.dev/manual/nix/development/development/building.html) for information on building Nix and running its tests.
3. Check the [Nix reference manual](https://nixos.org/manual/nix/unstable/contributing/hacking.html) for information on building Nix and running its tests.
For contributions to the command line interface, please check the [CLI guidelines](https://nix.dev/manual/nix/development/development/cli-guideline.html).
For contributions to the command line interface, please check the [CLI guidelines](https://nixos.org/manual/nix/unstable/contributing/cli-guideline.html).
4. Make your change!
@@ -69,7 +69,7 @@ Check out the [security policy](https://github.com/NixOS/nix/security/policy).
- [ ] API documentation in header files
- [ ] Code and comments are self-explanatory
- [ ] Commit message explains **why** the change was made
- [ ] New feature or incompatible change: [add a release note](https://nix.dev/manual/nix/development/development/contributing.html#add-a-release-note)
- [ ] New feature or incompatible change: [add a release note](https://nixos.org/manual/nix/stable/contributing/hacking#add-a-release-note)
7. If you need additional feedback or help to getting pull request into shape, ask other contributors using [@mentions](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#mentioning-people-and-teams).
@@ -78,7 +78,7 @@ Check out the [security policy](https://github.com/NixOS/nix/security/policy).
The Nix reference manual is hosted on https://nixos.org/manual/nix.
The underlying source files are located in [`doc/manual/src`](./doc/manual/src).
For small changes you can [use GitHub to edit these files](https://docs.github.com/en/repositories/working-with-files/managing-files/editing-files)
For larger changes see the [Nix reference manual](https://nix.dev/manual/nix/development/development/contributing.html).
For larger changes see the [Nix reference manual](https://nixos.org/manual/nix/unstable/contributing/hacking.html).
## Getting help

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@@ -18,7 +18,6 @@ makefiles = \
src/libfetchers/local.mk \
src/libmain/local.mk \
src/libexpr/local.mk \
src/libflake/local.mk \
src/libcmd/local.mk \
src/nix/local.mk \
src/libutil-c/local.mk \
@@ -46,15 +45,13 @@ makefiles += \
tests/unit/libstore-support/local.mk \
tests/unit/libfetchers/local.mk \
tests/unit/libexpr/local.mk \
tests/unit/libexpr-support/local.mk \
tests/unit/libflake/local.mk
tests/unit/libexpr-support/local.mk
endif
ifeq ($(ENABLE_FUNCTIONAL_TESTS), yes)
ifdef HOST_UNIX
makefiles += \
tests/functional/local.mk \
tests/functional/flakes/local.mk \
tests/functional/ca/local.mk \
tests/functional/git-hashing/local.mk \
tests/functional/dyn-drv/local.mk \
@@ -71,6 +68,14 @@ ifeq ($(ENABLE_DOC_GEN), yes)
makefiles-late += doc/manual/local.mk
endif
ifeq ($(ENABLE_INTERNAL_API_DOCS), yes)
makefiles-late += doc/internal-api/local.mk
endif
ifeq ($(ENABLE_EXTERNAL_API_DOCS), yes)
makefiles-late += doc/external-api/local.mk
endif
# Miscellaneous global Flags
OPTIMIZE = 1
@@ -93,7 +98,7 @@ ifdef HOST_WINDOWS
GLOBAL_LDFLAGS += -Wl,--export-all-symbols
endif
GLOBAL_CXXFLAGS += -g -Wall -Wdeprecated-copy -Wignored-qualifiers -Wimplicit-fallthrough -Werror=unused-result -Werror=suggest-override -include $(buildprefix)config.h -std=c++2a -I src
GLOBAL_CXXFLAGS += -g -Wall -Wdeprecated-copy -Wignored-qualifiers -Wimplicit-fallthrough -include $(buildprefix)config.h -std=c++2a -I src
# Include the main lib, causing rules to be defined
@@ -126,3 +131,17 @@ manual-html manpages:
@echo "Generated docs are disabled. Configure without '--disable-doc-gen', or avoid calling 'make manpages' and 'make manual-html'."
@exit 1
endif
ifneq ($(ENABLE_INTERNAL_API_DOCS), yes)
.PHONY: internal-api-html
internal-api-html:
@echo "Internal API docs are disabled. Configure with '--enable-internal-api-docs', or avoid calling 'make internal-api-html'."
@exit 1
endif
ifneq ($(ENABLE_EXTERNAL_API_DOCS), yes)
.PHONY: external-api-html
external-api-html:
@echo "External API docs are disabled. Configure with '--enable-external-api-docs', or avoid calling 'make external-api-html'."
@exit 1
endif

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@@ -11,6 +11,8 @@ EDITLINE_LIBS = @EDITLINE_LIBS@
ENABLE_BUILD = @ENABLE_BUILD@
ENABLE_DOC_GEN = @ENABLE_DOC_GEN@
ENABLE_FUNCTIONAL_TESTS = @ENABLE_FUNCTIONAL_TESTS@
ENABLE_INTERNAL_API_DOCS = @ENABLE_INTERNAL_API_DOCS@
ENABLE_EXTERNAL_API_DOCS = @ENABLE_EXTERNAL_API_DOCS@
ENABLE_S3 = @ENABLE_S3@
ENABLE_UNIT_TESTS = @ENABLE_UNIT_TESTS@
GTEST_LIBS = @GTEST_LIBS@

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@@ -4,34 +4,30 @@
[![Test](https://github.com/NixOS/nix/workflows/Test/badge.svg)](https://github.com/NixOS/nix/actions)
Nix is a powerful package manager for Linux and other Unix systems that makes package
management reliable and reproducible. Please refer to the [Nix manual](https://nix.dev/reference/nix-manual)
management reliable and reproducible. Please refer to the [Nix manual](https://nixos.org/nix/manual)
for more details.
## Installation and first steps
Visit [nix.dev](https://nix.dev) for [installation instructions](https://nix.dev/tutorials/install-nix) and [beginner tutorials](https://nix.dev/tutorials/first-steps).
Full reference documentation can be found in the [Nix manual](https://nix.dev/reference/nix-manual).
Full reference documentation can be found in the [Nix manual](https://nixos.org/nix/manual).
## Building and developing
## Building And Developing
Follow instructions in the Nix reference manual to [set up a development environment and build Nix from source](https://nix.dev/manual/nix/development/building.html).
See our [Hacking guide](https://nixos.org/manual/nix/unstable/contributing/hacking.html) in our manual for instruction on how to
set up a development environment and build Nix from source.
## Contributing
Check the [contributing guide](./CONTRIBUTING.md) if you want to get involved with developing Nix.
## Additional resources
## Additional Resources
Nix was created by Eelco Dolstra and developed as the subject of his PhD thesis [The Purely Functional Software Deployment Model](https://edolstra.github.io/pubs/phd-thesis.pdf), published 2006.
Today, a world-wide developer community contributes to Nix and the ecosystem that has grown around it.
- [The Nix, Nixpkgs, NixOS Community on nixos.org](https://nixos.org/)
- [Official documentation on nix.dev](https://nix.dev)
- [Nixpkgs](https://github.com/NixOS/nixpkgs) is [the largest, most up-to-date free software repository in the world](https://repology.org/repositories/graphs)
- [NixOS](https://github.com/NixOS/nixpkgs/tree/master/nixos) is a Linux distribution that can be configured fully declaratively
- [Discourse](https://discourse.nixos.org/)
- [Matrix](https://matrix.to/#/#nix:nixos.org)
- [Nix manual](https://nixos.org/nix/manual)
- [Nix jobsets on hydra.nixos.org](https://hydra.nixos.org/project/nix)
- [NixOS Discourse](https://discourse.nixos.org/)
- [Matrix - #nix:nixos.org](https://matrix.to/#/#nix:nixos.org)
## License

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@@ -1,36 +0,0 @@
# These are private dependencies with pkg-config files. What private
# means is that the dependencies are used by the library but they are
# *not* used (e.g. `#include`-ed) in any installed header file, and only
# in regular source code (`*.cc`) or private, uninstalled headers. They
# are thus part of the *implementation* of the library, but not its
# *interface*.
#
# See `man pkg-config` for some details.
deps_private = [ ]
# These are public dependencies with pkg-config files. Public is the
# opposite of private: these dependencies are used in installed header
# files. They are part of the interface (and implementation) of the
# library.
#
# N.B. This concept is mostly unrelated to our own concept of a public
# (stable) API, for consumption outside of the Nix repository.
# `libnixutil` is an unstable C++ library, whose public interface is
# likewise unstable. `libutilc` conversely is a hopefully-soon stable
# C library, whose public interface --- including public but not private
# dependencies --- will also likewise soon be stable.
#
# N.B. For distributions that care about "ABI" stability and not just
# "API" stability, the private dependencies also matter as they can
# potentially affect the public ABI.
deps_public = [ ]
# These are subproject deps (type == "internal"). They are other
# packages in `/src` in this repo. The private vs public distinction is
# the same as above.
deps_private_subproject = [ ]
deps_public_subproject = [ ]
# These are dependencencies without pkg-config files. Ideally they are
# just private, but they may also be public (e.g. boost).
deps_other = [ ]

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@@ -1,11 +0,0 @@
add_project_arguments(
'-Wdeprecated-copy',
'-Werror=suggest-override',
'-Werror=switch',
'-Werror=switch-enum',
'-Werror=unused-result',
'-Wignored-qualifiers',
'-Wimplicit-fallthrough',
'-Wno-deprecated-declarations',
language : 'cpp',
)

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@@ -1,11 +0,0 @@
if host_machine.system() == 'cygwin' or host_machine.system() == 'windows'
# Windows DLLs are stricter about symbol visibility than Unix shared
# objects --- see https://gcc.gnu.org/wiki/Visibility for details.
# This is a temporary sledgehammer to export everything like on Unix,
# and not detail with this yet.
#
# TODO do not do this, and instead do fine-grained export annotations.
linker_export_flags = ['-Wl,--export-all-symbols']
else
linker_export_flags = []
endif

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@@ -1,30 +0,0 @@
requires_private = []
foreach dep : deps_private_subproject
requires_private += dep.name()
endforeach
requires_private += deps_private
requires_public = []
foreach dep : deps_public_subproject
requires_public += dep.name()
endforeach
requires_public += deps_public
import('pkgconfig').generate(
this_library,
filebase : meson.project_name(),
name : 'Nix',
description : 'Nix Package Manager',
subdirs : ['nix'],
extra_cflags : ['-std=c++2a'],
requires : requires_public,
requires_private : requires_private,
libraries_private : libraries_private,
)
meson.override_dependency(meson.project_name(), declare_dependency(
include_directories : include_dirs,
link_with : this_library,
compile_args : ['-std=c++2a'],
dependencies : deps_public_subproject + deps_public,
))

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@@ -1,7 +0,0 @@
bash = find_program('bash', native: true)
gen_header = generator(
bash,
arguments : [ '-c', '{ echo \'R"__NIX_STR(\' && cat @INPUT@ && echo \')__NIX_STR"\'; } > "$1"', '_ignored_argv0', '@OUTPUT@' ],
output : '@PLAINNAME@.gen.hh',
)

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@@ -1,19 +0,0 @@
foreach maybe_subproject_dep : deps_private_maybe_subproject
if maybe_subproject_dep.type_name() == 'internal'
deps_private_subproject += maybe_subproject_dep
# subproject sadly no good for pkg-config module
deps_other += maybe_subproject_dep
else
deps_private += maybe_subproject_dep
endif
endforeach
foreach maybe_subproject_dep : deps_public_maybe_subproject
if maybe_subproject_dep.type_name() == 'internal'
deps_public_subproject += maybe_subproject_dep
# subproject sadly no good for pkg-config module
deps_other += maybe_subproject_dep
else
deps_public += maybe_subproject_dep
endif
endforeach

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@@ -1,6 +0,0 @@
# This is only conditional to work around
# https://github.com/mesonbuild/meson/issues/13293. It should be
# unconditional.
if not (host_machine.system() == 'windows' and cxx.get_id() == 'gcc')
deps_private += dependency('threads')
endif

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@@ -149,6 +149,11 @@ AC_ARG_ENABLE(unit-tests, AS_HELP_STRING([--disable-unit-tests],[Do not build th
ENABLE_UNIT_TESTS=$enableval, ENABLE_UNIT_TESTS=$ENABLE_BUILD)
AC_SUBST(ENABLE_UNIT_TESTS)
# Build external API docs by default
AC_ARG_ENABLE(external_api_docs, AS_HELP_STRING([--enable-external-api-docs],[Build API docs for Nix's C interface]),
external_api_docs=$enableval, external_api_docs=yes)
AC_SUBST(external_api_docs)
AS_IF(
[test "$ENABLE_BUILD" == "no" && test "$ENABLE_UNIT_TESTS" == "yes"],
[AC_MSG_ERROR([Cannot enable unit tests when building overall is disabled. Please do not pass '--enable-unit-tests' or do not pass '--disable-build'.])])
@@ -166,6 +171,15 @@ AS_IF(
[test "$ENABLE_BUILD" == "no" && test "$ENABLE_DOC_GEN" == "yes"],
[AC_MSG_ERROR([Cannot enable generated docs when building overall is disabled. Please do not pass '--enable-doc-gen' or do not pass '--disable-build'.])])
# Building without API docs is the default as Nix' C++ interfaces are internal and unstable.
AC_ARG_ENABLE(internal-api-docs, AS_HELP_STRING([--enable-internal-api-docs],[Build API docs for Nix's internal unstable C++ interfaces]),
ENABLE_INTERNAL_API_DOCS=$enableval, ENABLE_INTERNAL_API_DOCS=no)
AC_SUBST(ENABLE_INTERNAL_API_DOCS)
AC_ARG_ENABLE(external-api-docs, AS_HELP_STRING([--enable-external-api-docs],[Build API docs for Nix's external unstable C interfaces]),
ENABLE_EXTERNAL_API_DOCS=$enableval, ENABLE_EXTERNAL_API_DOCS=no)
AC_SUBST(ENABLE_EXTERNAL_API_DOCS)
AS_IF(
[test "$ENABLE_FUNCTIONAL_TESTS" == "yes" || test "$ENABLE_DOC_GEN" == "yes"],
[NEED_PROG(jq, jq)])
@@ -340,6 +354,13 @@ AC_CHECK_HEADERS([aws/s3/S3Client.h],
AC_SUBST(ENABLE_S3, [$enable_s3])
AC_LANG_POP(C++)
if test -n "$enable_s3"; then
declare -a aws_version_tokens=($(printf '#include <aws/core/VersionConfig.h>\nAWS_SDK_VERSION_STRING' | $CPP $CPPFLAGS - | grep -v '^#.*' | sed 's/"//g' | tr '.' ' '))
AC_DEFINE_UNQUOTED([AWS_VERSION_MAJOR], ${aws_version_tokens@<:@0@:>@}, [Major version of aws-sdk-cpp.])
AC_DEFINE_UNQUOTED([AWS_VERSION_MINOR], ${aws_version_tokens@<:@1@:>@}, [Minor version of aws-sdk-cpp.])
AC_DEFINE_UNQUOTED([AWS_VERSION_PATCH], ${aws_version_tokens@<:@2@:>@}, [Patch version of aws-sdk-cpp.])
fi
# Whether to use the Boehm garbage collector.
AC_ARG_ENABLE(gc, AS_HELP_STRING([--enable-gc],[enable garbage collection in the Nix expression evaluator (requires Boehm GC) [default=yes]]),
@@ -348,14 +369,6 @@ if test "$gc" = yes; then
PKG_CHECK_MODULES([BDW_GC], [bdw-gc])
CXXFLAGS="$BDW_GC_CFLAGS $CXXFLAGS"
AC_DEFINE(HAVE_BOEHMGC, 1, [Whether to use the Boehm garbage collector.])
# See `fixupBoehmStackPointer`, for the integration between Boehm GC
# and Boost coroutines.
old_CFLAGS="$CFLAGS"
# Temporary set `-pthread` just for the next check
CFLAGS="$CFLAGS -pthread"
AC_CHECK_FUNCS([pthread_attr_get_np pthread_getattr_np])
CFLAGS="$old_CFLAGS"
fi
AS_IF([test "$ENABLE_UNIT_TESTS" == "yes"],[
@@ -393,11 +406,6 @@ AS_CASE(["$enable_markdown"],
PKG_CHECK_MODULES([LIBGIT2], [libgit2])
# Look for toml11, a required dependency.
AC_LANG_PUSH(C++)
AC_CHECK_HEADER([toml.hpp], [], [AC_MSG_ERROR([toml11 is not found.])])
AC_LANG_POP(C++)
# Setuid installations.
AC_CHECK_FUNCS([setresuid setreuid lchown])

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@@ -0,0 +1,99 @@
diff --git a/darwin_stop_world.c b/darwin_stop_world.c
index 0468aaec..b348d869 100644
--- a/darwin_stop_world.c
+++ b/darwin_stop_world.c
@@ -356,6 +356,7 @@ GC_INNER void GC_push_all_stacks(void)
int nthreads = 0;
word total_size = 0;
mach_msg_type_number_t listcount = (mach_msg_type_number_t)THREAD_TABLE_SZ;
+ size_t stack_limit;
if (!EXPECT(GC_thr_initialized, TRUE))
GC_thr_init();
@@ -411,6 +412,19 @@ GC_INNER void GC_push_all_stacks(void)
GC_push_all_stack_sections(lo, hi, p->traced_stack_sect);
}
if (altstack_lo) {
+ // When a thread goes into a coroutine, we lose its original sp until
+ // control flow returns to the thread.
+ // While in the coroutine, the sp points outside the thread stack,
+ // so we can detect this and push the entire thread stack instead,
+ // as an approximation.
+ // We assume that the coroutine has similarly added its entire stack.
+ // This could be made accurate by cooperating with the application
+ // via new functions and/or callbacks.
+ stack_limit = pthread_get_stacksize_np(p->id);
+ if (altstack_lo >= altstack_hi || altstack_lo < altstack_hi - stack_limit) { // sp outside stack
+ altstack_lo = altstack_hi - stack_limit;
+ }
+
total_size += altstack_hi - altstack_lo;
GC_push_all_stack(altstack_lo, altstack_hi);
}
diff --git a/include/gc.h b/include/gc.h
index edab6c22..f2c61282 100644
--- a/include/gc.h
+++ b/include/gc.h
@@ -2172,6 +2172,11 @@ GC_API void GC_CALL GC_win32_free_heap(void);
(*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_ignore_off_page)
#endif /* _AMIGA && !GC_AMIGA_MAKINGLIB */
+#if !__APPLE__
+/* Patch doesn't work on apple */
+#define NIX_BOEHM_PATCH_VERSION 1
+#endif
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/pthread_stop_world.c b/pthread_stop_world.c
index b5d71e62..aed7b0bf 100644
--- a/pthread_stop_world.c
+++ b/pthread_stop_world.c
@@ -768,6 +768,8 @@ STATIC void GC_restart_handler(int sig)
/* world is stopped. Should not fail if it isn't. */
GC_INNER void GC_push_all_stacks(void)
{
+ size_t stack_limit;
+ pthread_attr_t pattr;
GC_bool found_me = FALSE;
size_t nthreads = 0;
int i;
@@ -851,6 +853,37 @@ GC_INNER void GC_push_all_stacks(void)
hi = p->altstack + p->altstack_size;
/* FIXME: Need to scan the normal stack too, but how ? */
/* FIXME: Assume stack grows down */
+ } else {
+#ifdef HAVE_PTHREAD_ATTR_GET_NP
+ if (!pthread_attr_init(&pattr)
+ || !pthread_attr_get_np(p->id, &pattr))
+#else /* HAVE_PTHREAD_GETATTR_NP */
+ if (pthread_getattr_np(p->id, &pattr))
+#endif
+ {
+ ABORT("GC_push_all_stacks: pthread_getattr_np failed!");
+ }
+ if (pthread_attr_getstacksize(&pattr, &stack_limit)) {
+ ABORT("GC_push_all_stacks: pthread_attr_getstacksize failed!");
+ }
+ if (pthread_attr_destroy(&pattr)) {
+ ABORT("GC_push_all_stacks: pthread_attr_destroy failed!");
+ }
+ // When a thread goes into a coroutine, we lose its original sp until
+ // control flow returns to the thread.
+ // While in the coroutine, the sp points outside the thread stack,
+ // so we can detect this and push the entire thread stack instead,
+ // as an approximation.
+ // We assume that the coroutine has similarly added its entire stack.
+ // This could be made accurate by cooperating with the application
+ // via new functions and/or callbacks.
+ #ifndef STACK_GROWS_UP
+ if (lo >= hi || lo < hi - stack_limit) { // sp outside stack
+ lo = hi - stack_limit;
+ }
+ #else
+ #error "STACK_GROWS_UP not supported in boost_coroutine2 (as of june 2021), so we don't support it in Nix."
+ #endif
}
GC_push_all_stack_sections(lo, hi, traced_stack_sect);
# ifdef STACK_GROWS_UP

View File

@@ -0,0 +1,12 @@
diff --git a/include/gc_allocator.h b/include/gc_allocator.h
index 597c7f13..587286be 100644
--- a/include/gc_allocator.h
+++ b/include/gc_allocator.h
@@ -312,6 +312,7 @@ public:
template<>
class traceable_allocator<void> {
+public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef void* pointer;

View File

@@ -12,9 +12,7 @@ PROJECT_NAME = "Nix"
# could be handy for archiving the generated documentation or if some version
# control system is used.
PROJECT_NUMBER = @PROJECT_NUMBER@
OUTPUT_DIRECTORY = @OUTPUT_DIRECTORY@
PROJECT_NUMBER = @PACKAGE_VERSION@
# Using the PROJECT_BRIEF tag one can provide an optional one line description
# for a project that appears at the top of each page and should give viewer a
@@ -38,10 +36,10 @@ GENERATE_LATEX = NO
# so they can expand variables despite configure variables.
INPUT = \
@src@/src/libutil-c \
@src@/src/libexpr-c \
@src@/src/libstore-c \
@src@/doc/external-api/README.md
src/libutil-c \
src/libexpr-c \
src/libstore-c \
doc/external-api/README.md
FILE_PATTERNS = nix_api_*.h *.md
@@ -51,6 +49,7 @@ FILE_PATTERNS = nix_api_*.h *.md
# RECURSIVE has no effect here.
# This tag requires that the tag SEARCH_INCLUDES is set to YES.
INCLUDE_PATH = @RAPIDCHECK_HEADERS@
EXCLUDE_PATTERNS = *_internal.h
GENERATE_TREEVIEW = YES
OPTIMIZE_OUTPUT_FOR_C = YES

View File

@@ -0,0 +1,7 @@
$(docdir)/external-api/html/index.html $(docdir)/external-api/latex: $(d)/doxygen.cfg src/lib*-c/*.h
mkdir -p $(docdir)/external-api
{ cat $< ; echo "OUTPUT_DIRECTORY=$(docdir)/external-api" ; } | doxygen -
# Generate the HTML API docs for Nix's unstable C bindings
.PHONY: external-api-html
external-api-html: $(docdir)/external-api/html/index.html

View File

@@ -12,9 +12,7 @@ PROJECT_NAME = "Nix"
# could be handy for archiving the generated documentation or if some version
# control system is used.
PROJECT_NUMBER = @PROJECT_NUMBER@
OUTPUT_DIRECTORY = @OUTPUT_DIRECTORY@
PROJECT_NUMBER = @PACKAGE_VERSION@
# Using the PROJECT_BRIEF tag one can provide an optional one line description
# for a project that appears at the top of each page and should give viewer a
@@ -38,27 +36,27 @@ GENERATE_LATEX = NO
# so they can expand variables despite configure variables.
INPUT = \
@src@/libcmd \
@src@/libexpr \
@src@/libexpr/flake \
@src@/nix-expr-tests \
@src@/nix-expr-tests/value \
@src@/nix-expr-test-support/test \
@src@/nix-expr-test-support/test/value \
@src@/libexpr/value \
@src@/libfetchers \
@src@/libmain \
@src@/libstore \
@src@/libstore/build \
@src@/libstore/builtins \
@src@/nix-store-tests \
@src@/nix-store-test-support/test \
@src@/libutil \
@src@/nix-util-tests \
@src@/nix-util-test-support/test \
@src@/nix \
@src@/nix-env \
@src@/nix-store
src/libcmd \
src/libexpr \
src/libexpr/flake \
tests/unit/libexpr \
tests/unit/libexpr/value \
tests/unit/libexpr/test \
tests/unit/libexpr/test/value \
src/libexpr/value \
src/libfetchers \
src/libmain \
src/libstore \
src/libstore/build \
src/libstore/builtins \
tests/unit/libstore \
tests/unit/libstore/test \
src/libutil \
tests/unit/libutil \
tests/unit/libutil/test \
src/nix \
src/nix-env \
src/nix-store
# If the MACRO_EXPANSION tag is set to YES, doxygen will expand all macro names
# in the source code. If set to NO, only conditional compilation will be

View File

@@ -0,0 +1,7 @@
$(docdir)/internal-api/html/index.html $(docdir)/internal-api/latex: $(d)/doxygen.cfg src/**/*.hh
mkdir -p $(docdir)/internal-api
{ cat $< ; echo "OUTPUT_DIRECTORY=$(docdir)/internal-api" ; } | doxygen -
# Generate the HTML API docs for Nix's unstable internal interfaces.
.PHONY: internal-api-html
internal-api-html: $(docdir)/internal-api/html/index.html

View File

@@ -0,0 +1,31 @@
let
inherit (builtins) concatStringsSep attrValues mapAttrs;
inherit (import <nix/utils.nix>) optionalString squash;
in
builtinsInfo:
let
showBuiltin = name: { doc, type, impure-only }:
let
type' = optionalString (type != null) " (${type})";
impureNotice = optionalString impure-only ''
> **Note**
>
> Not available in [pure evaluation mode](@docroot@/command-ref/conf-file.md#conf-pure-eval).
'';
in
squash ''
<dt id="builtins-${name}">
<a href="#builtins-${name}"><code>${name}</code></a>${type'}
</dt>
<dd>
${doc}
${impureNotice}
</dd>
'';
in
concatStringsSep "\n" (attrValues (mapAttrs showBuiltin builtinsInfo))

View File

@@ -5,14 +5,12 @@ in
builtinsInfo:
let
showBuiltin = name: { doc, type ? null, args ? [ ], experimental-feature ? null, impure-only ? false }:
showBuiltin = name: { doc, args, arity, experimental-feature }:
let
type' = optionalString (type != null) " (${type})";
experimentalNotice = optionalString (experimental-feature != null) ''
> **Note**
>
> This function is only available if the [`${experimental-feature}` experimental feature](@docroot@/development/experimental-features.md#xp-feature-${experimental-feature}) is enabled.
> This function is only available if the [`${experimental-feature}` experimental feature](@docroot@/contributing/experimental-features.md#xp-feature-${experimental-feature}) is enabled.
>
> For example, include the following in [`nix.conf`](@docroot@/command-ref/conf-file.md):
>
@@ -20,26 +18,18 @@ let
> extra-experimental-features = ${experimental-feature}
> ```
'';
impureNotice = optionalString impure-only ''
> **Note**
>
> Not available in [pure evaluation mode](@docroot@/command-ref/conf-file.md#conf-pure-eval).
'';
in
squash ''
<dt id="builtins-${name}">
<a href="#builtins-${name}"><code>${name}${listArgs args}</code></a>${type'}
<a href="#builtins-${name}"><code>${name} ${listArgs args}</code></a>
</dt>
<dd>
${experimentalNotice}
${doc}
${impureNotice}
</dd>
'';
listArgs = args: concatStringsSep "" (map (s: " <var>${s}</var>") args);
listArgs = args: concatStringsSep " " (map (s: "<var>${s}</var>") args);
in
concatStringsSep "\n" (attrValues (mapAttrs showBuiltin builtinsInfo))

View File

@@ -38,7 +38,7 @@ let
result = ''
> **Warning** \
> This program is
> [**experimental**](@docroot@/development/experimental-features.md#xp-feature-nix-command)
> [**experimental**](@docroot@/contributing/experimental-features.md#xp-feature-nix-command)
> and its interface is subject to change.
# Name
@@ -116,12 +116,9 @@ let
storeInfo = commandInfo.stores;
inherit inlineHTML;
};
hasInfix = infix: content:
builtins.stringLength content != builtins.stringLength (replaceStrings [ infix ] [ "" ] content);
in
optionalString (details ? doc) (
# An alternate implementation with builtins.match stack overflowed on some systems.
if hasInfix "@store-types@" details.doc
if match ".*@store-types@.*" details.doc != null
then help-stores
else details.doc
);

View File

@@ -33,10 +33,10 @@ let
> **Warning**
>
> This setting is part of an
> [experimental feature](@docroot@/development/experimental-features.md).
> [experimental feature](@docroot@/contributing/experimental-features.md).
>
> To change this setting, make sure the
> [`${experimentalFeature}` experimental feature](@docroot@/development/experimental-features.md#xp-feature-${experimentalFeature})
> [`${experimentalFeature}` experimental feature](@docroot@/contributing/experimental-features.md#xp-feature-${experimentalFeature})
> is enabled.
> For example, include the following in [`nix.conf`](@docroot@/command-ref/conf-file.md):
>

View File

@@ -32,10 +32,10 @@ let
> **Warning**
>
> This store is part of an
> [experimental feature](@docroot@/development/experimental-features.md).
> [experimental feature](@docroot@/contributing/experimental-features.md).
>
> To use this store, make sure the
> [`${experimentalFeature}` experimental feature](@docroot@/development/experimental-features.md#xp-feature-${experimentalFeature})
> [`${experimentalFeature}` experimental feature](@docroot@/contributing/experimental-features.md#xp-feature-${experimentalFeature})
> is enabled.
> For example, include the following in [`nix.conf`](@docroot@/command-ref/conf-file.md):
>

View File

@@ -4,6 +4,6 @@ with import <nix/utils.nix>;
let
showExperimentalFeature = name: doc:
''
- [`${name}`](@docroot@/development/experimental-features.md#xp-feature-${name})
- [`${name}`](@docroot@/contributing/experimental-features.md#xp-feature-${name})
'';
in xps: indent " " (concatStrings (attrValues (mapAttrs showExperimentalFeature xps)))

View File

@@ -95,7 +95,7 @@ $(d)/nix-profiles.5: $(d)/src/command-ref/files/profiles.md
$(trace-gen) lowdown -sT man --nroff-nolinks -M section=5 $^.tmp -o $@
@rm $^.tmp
$(d)/src/SUMMARY.md: $(d)/src/SUMMARY.md.in $(d)/src/SUMMARY-rl-next.md $(d)/src/store/types $(d)/src/command-ref/new-cli $(d)/src/development/experimental-feature-descriptions.md
$(d)/src/SUMMARY.md: $(d)/src/SUMMARY.md.in $(d)/src/SUMMARY-rl-next.md $(d)/src/store/types $(d)/src/command-ref/new-cli $(d)/src/contributing/experimental-feature-descriptions.md
@cp $< $@
@$(call process-includes,$@,$@)
@@ -124,7 +124,7 @@ $(d)/conf-file.json: $(doc_nix)
$(trace-gen) $(dummy-env) $(doc_nix) config show --json --experimental-features nix-command > $@.tmp
@mv $@.tmp $@
$(d)/src/development/experimental-feature-descriptions.md: $(d)/xp-features.json $(d)/utils.nix $(d)/generate-xp-features.nix $(doc_nix)
$(d)/src/contributing/experimental-feature-descriptions.md: $(d)/xp-features.json $(d)/utils.nix $(d)/generate-xp-features.nix $(doc_nix)
@rm -rf $@ $@.tmp
$(trace-gen) $(nix-eval) --write-to $@.tmp --expr 'import doc/manual/generate-xp-features.nix (builtins.fromJSON (builtins.readFile $<))'
@mv $@.tmp $@
@@ -140,10 +140,16 @@ $(d)/xp-features.json: $(doc_nix)
$(d)/src/language/builtins.md: $(d)/language.json $(d)/generate-builtins.nix $(d)/src/language/builtins-prefix.md $(doc_nix)
@cat doc/manual/src/language/builtins-prefix.md > $@.tmp
$(trace-gen) $(nix-eval) --expr 'import doc/manual/generate-builtins.nix (builtins.fromJSON (builtins.readFile $<))' >> $@.tmp;
$(trace-gen) $(nix-eval) --expr 'import doc/manual/generate-builtins.nix (builtins.fromJSON (builtins.readFile $<)).builtins' >> $@.tmp;
@cat doc/manual/src/language/builtins-suffix.md >> $@.tmp
@mv $@.tmp $@
$(d)/src/language/builtin-constants.md: $(d)/language.json $(d)/generate-builtin-constants.nix $(d)/src/language/builtin-constants-prefix.md $(doc_nix)
@cat doc/manual/src/language/builtin-constants-prefix.md > $@.tmp
$(trace-gen) $(nix-eval) --expr 'import doc/manual/generate-builtin-constants.nix (builtins.fromJSON (builtins.readFile $<)).constants' >> $@.tmp;
@cat doc/manual/src/language/builtin-constants-suffix.md >> $@.tmp
@mv $@.tmp $@
$(d)/language.json: $(doc_nix)
$(trace-gen) $(dummy-env) $(doc_nix) __dump-language > $@.tmp
@mv $@.tmp $@
@@ -207,11 +213,11 @@ doc/manual/generated/man1/nix3-manpages: $(d)/src/command-ref/new-cli
done
@touch $@
# the `! -name 'documentation.md'` filter excludes the one place where
# the `! -name 'contributing.md'` filter excludes the one place where
# `@docroot@` is to be preserved for documenting the mechanism
# FIXME: maybe contributing guides should live right next to the code
# instead of in the manual
$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/anchors.jq $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/store/types $(d)/src/command-ref/new-cli $(d)/src/development/experimental-feature-descriptions.md $(d)/src/command-ref/conf-file.md $(d)/src/language/builtins.md $(d)/src/release-notes/rl-next.md $(d)/src/figures $(d)/src/favicon.png $(d)/src/favicon.svg
$(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/anchors.jq $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/store/types $(d)/src/command-ref/new-cli $(d)/src/contributing/experimental-feature-descriptions.md $(d)/src/command-ref/conf-file.md $(d)/src/language/builtins.md $(d)/src/language/builtin-constants.md $(d)/src/release-notes/rl-next.md $(d)/src/figures $(d)/src/favicon.png $(d)/src/favicon.svg
$(trace-gen) \
tmp="$$(mktemp -d)"; \
cp -r doc/manual "$$tmp"; \

View File

@@ -1,7 +1,7 @@
// redirect rules for URL fragments (client-side) to prevent link rot.
// this must be done on the client side, as web servers do not see the fragment part of the URL.
// it will only work with JavaScript enabled in the browser, but this is the best we can do here.
// see src/_redirects for path redirects (server-side)
// see ./_redirects for path redirects (client-side)
// redirects are declared as follows:
// each entry has as its key a path matching the requested URL path, relative to the mdBook document root.
@@ -143,7 +143,7 @@ const redirects = {
"opt-timeout": "command-ref/opt-common.html#opt-timeout",
"sec-common-options": "command-ref/opt-common.html",
"ch-utilities": "command-ref/utilities.html",
"chap-hacking": "development/building.html",
"chap-hacking": "contributing/hacking.html",
"adv-attr-allowSubstitutes": "language/advanced-attributes.html#adv-attr-allowSubstitutes",
"adv-attr-allowedReferences": "language/advanced-attributes.html#adv-attr-allowedReferences",
"adv-attr-allowedRequisites": "language/advanced-attributes.html#adv-attr-allowedRequisites",
@@ -238,12 +238,12 @@ const redirects = {
"attr-system": "language/derivations.html#attr-system",
"ssec-derivation": "language/derivations.html",
"ch-expression-language": "language/index.html",
"sec-constructs": "language/syntax.html",
"sect-let-language": "language/syntax.html#let-expressions",
"ss-functions": "language/syntax.html#functions",
"sec-constructs": "language/constructs.html",
"sect-let-language": "language/constructs.html#let-language",
"ss-functions": "language/constructs.html#functions",
"sec-language-operators": "language/operators.html",
"table-operators": "language/operators.html",
"ssec-values": "language/types.html",
"ssec-values": "language/values.html",
"gloss-closure": "glossary.html#gloss-closure",
"gloss-derivation": "glossary.html#gloss-derivation",
"gloss-deriver": "glossary.html#gloss-deriver",
@@ -335,22 +335,18 @@ const redirects = {
"ssec-relnotes-2.2": "release-notes/rl-2.2.html",
"ssec-relnotes-2.3": "release-notes/rl-2.3.html",
},
"language/types.html": {
"language/values.html": {
"simple-values": "#primitives",
"lists": "#list",
"strings": "#string",
"attribute-sets": "#attribute-set",
"type-number": "#type-int",
},
"language/syntax.html": {
"scoping-rules": "scoping.html",
},
"installation/installing-binary.html": {
"linux": "uninstall.html#linux",
"macos": "uninstall.html#macos",
"uninstalling": "uninstall.html",
},
"development/building.html": {
"contributing/hacking.html": {
"nix-with-flakes": "#building-nix-with-flakes",
"classic-nix": "#building-nix",
"running-tests": "testing.html#running-tests",
@@ -361,12 +357,7 @@ const redirects = {
"installer-tests": "testing.html#installer-tests",
"one-time-setup": "testing.html#one-time-setup",
"using-the-ci-generated-installer-for-manual-testing": "testing.html#using-the-ci-generated-installer-for-manual-testing",
"characterization-testing": "testing.html#characterisation-testing-unit",
"add-a-release-note": "contributing.html#add-a-release-note",
"add-an-entry": "contributing.html#add-an-entry",
"build-process": "contributing.html#build-process",
"reverting": "contributing.html#reverting",
"branches": "contributing.html#branches",
"characterization-testing": "#characterisation-testing-unit",
},
"glossary.html": {
"gloss-local-store": "store/types/local-store.html",

View File

@@ -0,0 +1,6 @@
---
synopsis: Show all FOD errors with `nix build --keep-going`
---
`nix build --keep-going` now behaves consistently with `nix-build --keep-going`. This means
that if e.g. multiple FODs fail to build, all hash mismatches are displayed.

View File

@@ -0,0 +1,12 @@
---
synopsis: Modify `nix derivation {add,show}` JSON format
issues: 9866
prs: 10722
---
The JSON format for derivations has been slightly revised to better conform to our [JSON guidelines](@docroot@contributing/cli-guideline#returning-future-proof-json).
In particular, the hash algorithm and content addressing method of content-addresed derivation outputs is now separated into two fields `hashAlgo` and `method`,
rather than one field with an arcane `:`-separated format.
This JSON format is only used by the experimental `nix derivation` family of commands, at this time.
Future revisions are expected as the JSON format is still not entirely in compliance even after these changes.

View File

@@ -0,0 +1,28 @@
---
synopsis: Warn on unknown settings anywhere in the command line
prs: 10701
---
All `nix` commands will now properly warn when an unknown option is specified anywhere in the command line.
Before:
```console
$ nix-instantiate --option foobar baz --expr '{}'
warning: unknown setting 'foobar'
$ nix-instantiate '{}' --option foobar baz --expr
$ nix eval --expr '{}' --option foobar baz
{ }
```
After:
```console
$ nix-instantiate --option foobar baz --expr '{}'
warning: unknown setting 'foobar'
$ nix-instantiate '{}' --option foobar baz --expr
warning: unknown setting 'foobar'
$ nix eval --expr '{}' --option foobar baz
warning: unknown setting 'foobar'
{ }
```

View File

@@ -25,18 +25,17 @@
- [Store Types](store/types/index.md)
{{#include ./store/types/SUMMARY.md}}
- [Nix Language](language/index.md)
- [Data Types](language/types.md)
- [String context](language/string-context.md)
- [Syntax and semantics](language/syntax.md)
- [Identifiers](language/identifiers.md)
- [Scoping rules](language/scope.md)
- [Data Types](language/values.md)
- [Language Constructs](language/constructs.md)
- [String interpolation](language/string-interpolation.md)
- [Lookup path](language/constructs/lookup-path.md)
- [String context](language/string-context.md)
- [Operators](language/operators.md)
- [Built-ins](language/builtins.md)
- [Derivations](language/derivations.md)
- [Advanced Attributes](language/advanced-attributes.md)
- [Import From Derivation](language/import-from-derivation.md)
- [Derivations](language/derivations.md)
- [Advanced Attributes](language/advanced-attributes.md)
- [Import From Derivation](language/import-from-derivation.md)
- [Built-in Constants](language/builtin-constants.md)
- [Built-in Functions](language/builtins.md)
- [Package Management](package-management/index.md)
- [Profiles](package-management/profiles.md)
- [Garbage Collection](package-management/garbage-collection.md)
@@ -116,19 +115,15 @@
- [Derivation "ATerm" file format](protocols/derivation-aterm.md)
- [C API](c-api.md)
- [Glossary](glossary.md)
- [Development](development/index.md)
- [Building](development/building.md)
- [Testing](development/testing.md)
- [Documentation](development/documentation.md)
- [CLI guideline](development/cli-guideline.md)
- [JSON guideline](development/json-guideline.md)
- [C++ style guide](development/cxx.md)
- [Experimental Features](development/experimental-features.md)
- [Contributing](development/contributing.md)
- [Contributing](contributing/index.md)
- [Hacking](contributing/hacking.md)
- [Testing](contributing/testing.md)
- [Documentation](contributing/documentation.md)
- [Experimental Features](contributing/experimental-features.md)
- [CLI guideline](contributing/cli-guideline.md)
- [C++ style guide](contributing/cxx.md)
- [Releases](release-notes/index.md)
{{#include ./SUMMARY-rl-next.md}}
- [Release 2.24 (2024-07-31)](release-notes/rl-2.24.md)
- [Release 2.23 (2024-06-03)](release-notes/rl-2.23.md)
- [Release 2.22 (2024-04-23)](release-notes/rl-2.22.md)
- [Release 2.21 (2024-03-11)](release-notes/rl-2.21.md)
- [Release 2.20 (2024-01-29)](release-notes/rl-2.20.md)

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@@ -1,5 +1,5 @@
# redirect rules for paths (server-side) to prevent link rot.
# see ../redirects.js for redirects based on URL fragments (client-side)
# see ./redirects.js for redirects based on URL fragments (client-side)
#
# concrete user story this supports:
# - user finds URL to the manual for Nix x.y
@@ -20,24 +20,13 @@
/command-ref/command-ref /command-ref 301!
/contributing/contributing /development 301!
/contributing /development 301!
/contributing/hacking /development/building 301!
/contributing/testing /development/testing 301!
/contributing/documentation /development/documentation 301!
/contributing/experimental-features /development/experimental-features 301!
/contributing/cli-guideline /development/cli-guideline 301!
/contributing/json-guideline /development/json-guideline 301!
/contributing/cxx /development/cxx 301!
/contributing/contributing /contributing 301!
/expressions/expression-language /language/ 301!
/expressions/language-constructs /language/constructs 301!
/expressions/language-operators /language/operators 301!
/expressions/language-values /language/values 301!
/expressions/* /language/:splat 301!
/language/values /language/types 301!
/language/constructs /language/syntax 301!
/language/builtin-constants /language/builtins 301!
/installation/installation /installation 301!

View File

@@ -10,7 +10,7 @@ See:
- [Matrix Room *Nix Bindings*](https://matrix.to/#/#nix-bindings:nixos.org) for discussion and questions.
- [Stabilisation Milestone](https://github.com/NixOS/nix/milestone/52)
- [Other C API PRs and issues](https://github.com/NixOS/nix/labels/c%20api)
- [Contributing C API Documentation](development/documentation.md#c-api-documentation), including how to build it locally.
- [Contributing C API Documentation](contributing/documentation.md#c-api-documentation), including how to build it locally.
[Getting Started]: https://hydra.nixos.org/job/nix/master/external-api-docs/latest/download-by-type/doc/external-api-docs
[Index]: https://hydra.nixos.org/job/nix/master/external-api-docs/latest/download-by-type/doc/external-api-docs/globals.html

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@@ -9,26 +9,22 @@ Most Nix commands interpret the following environment variables:
- <span id="env-NIX_PATH">[`NIX_PATH`](#env-NIX_PATH)</span>
A colon-separated list of search path entries used to resolve [lookup paths](@docroot@/language/constructs/lookup-path.md).
A colon-separated list of directories used to look up the location of Nix
expressions using [paths](@docroot@/language/values.md#type-path)
enclosed in angle brackets (i.e., `<path>`),
e.g. `/home/eelco/Dev:/etc/nixos`. It can be extended using the
[`-I` option](@docroot@/command-ref/opt-common.md#opt-I).
This environment variable overrides the value of the [`nix-path` configuration setting](@docroot@/command-ref/conf-file.md#conf-nix-path).
If `NIX_PATH` is not set at all, Nix will fall back to the following list in [impure](@docroot@/command-ref/conf-file.md#conf-pure-eval) and [unrestricted](@docroot@/command-ref/conf-file.md#conf-restrict-eval) evaluation mode:
It can be extended using the [`-I` option](@docroot@/command-ref/opt-common.md#opt-I).
> **Example**
>
> ```bash
> $ export NIX_PATH=`/home/eelco/Dev:nixos-config=/etc/nixos
> ```
1. `$HOME/.nix-defexpr/channels`
2. `nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixpkgs`
3. `/nix/var/nix/profiles/per-user/root/channels`
If `NIX_PATH` is set to an empty string, resolving search paths will always fail.
For example, attempting to use `<nixpkgs>` will produce:
> **Example**
>
> ```bash
> $ NIX_PATH= nix-instantiate --eval '<nixpkgs>'
> error: file 'nixpkgs' was not found in the Nix search path (add it using $NIX_PATH or -I)
> ```
error: file 'nixpkgs' was not found in the Nix search path
- <span id="env-NIX_IGNORE_SYMLINK_STORE">[`NIX_IGNORE_SYMLINK_STORE`](#env-NIX_IGNORE_SYMLINK_STORE)</span>

View File

@@ -1,6 +1,6 @@
# Experimental Commands
This section lists [experimental commands](@docroot@/development/experimental-features.md#xp-feature-nix-command).
This section lists [experimental commands](@docroot@/contributing/experimental-features.md#xp-feature-nix-command).
> **Warning**
>

View File

@@ -55,20 +55,20 @@ All options not listed here are passed to
[`nix-store --realise`](nix-store/realise.md),
except for `--arg` and `--attr` / `-A` which are passed to [`nix-instantiate`](nix-instantiate.md).
- <span id="opt-no-out-link">[`--no-out-link`](#opt-no-out-link)<span>
- <span id="opt-no-out-link">[`--no-out-link`](#opt-no-out-link)<span>
Do not create a symlink to the output path. Note that as a result
the output does not become a root of the garbage collector, and so
might be deleted by `nix-store --gc`.
Do not create a symlink to the output path. Note that as a result
the output does not become a root of the garbage collector, and so
might be deleted by `nix-store --gc`.
- <span id="opt-dry-run">[`--dry-run`](#opt-dry-run)</span>
- <span id="opt-dry-run">[`--dry-run`](#opt-dry-run)</span>
Show what store paths would be built or downloaded.
Show what store paths would be built or downloaded.
- <span id="opt-out-link">[`--out-link`](#opt-out-link)</span> / `-o` *outlink*
- <span id="opt-out-link">[`--out-link`](#opt-out-link)</span> / `-o` *outlink*
Change the name of the symlink to the output path created from
`result` to *outlink*.
Change the name of the symlink to the output path created from
`result` to *outlink*.
{{#include ./status-build-failure.md}}

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@@ -27,46 +27,40 @@ The moving parts of channels are:
This command has the following operations:
- `--add` *url* \[*name*\]
- `--add` *url* \[*name*\]\
Add a channel *name* located at *url* to the list of subscribed channels.
If *name* is omitted, default to the last component of *url*, with the suffixes `-stable` or `-unstable` removed.
Add a channel *name* located at *url* to the list of subscribed channels.
If *name* is omitted, default to the last component of *url*, with the suffixes `-stable` or `-unstable` removed.
> **Note**
>
> `--add` does not automatically perform an update.
> Use `--update` explicitly.
> **Note**
>
> `--add` does not automatically perform an update.
> Use `--update` explicitly.
A channel URL must point to a directory containing a file `nixexprs.tar.gz`.
At the top level, that tarball must contain a single directory with a `default.nix` file that serves as the channels entry point.
A channel URL must point to a directory containing a file `nixexprs.tar.gz`.
At the top level, that tarball must contain a single directory with a `default.nix` file that serves as the channels entry point.
- `--remove` *name*\
Remove the channel *name* from the list of subscribed channels.
- `--remove` *name*
- `--list`\
Print the names and URLs of all subscribed channels on standard output.
Remove the channel *name* from the list of subscribed channels.
- `--update` \[*names*…\]\
Download the Nix expressions of subscribed channels and create a new generation.
Update all channels if none is specified, and only those included in *names* otherwise.
- `--list`
- `--list-generations`\
Prints a list of all the current existing generations for the
channel profile.
Print the names and URLs of all subscribed channels on standard output.
Works the same way as
```
nix-env --profile /nix/var/nix/profiles/per-user/$USER/channels --list-generations
```
- `--update` \[*names*…\]
Download the Nix expressions of subscribed channels and create a new generation.
Update all channels if none is specified, and only those included in *names* otherwise.
- `--list-generations`
Prints a list of all the current existing generations for the
channel profile.
Works the same way as
```
nix-env --profile /nix/var/nix/profiles/per-user/$USER/channels --list-generations
```
- `--rollback` \[*generation*\]
Revert channels to the state before the last call to `nix-channel --update`.
Optionally, you can specify a specific channel *generation* number to restore.
- `--rollback` \[*generation*\]\
Revert channels to the state before the last call to `nix-channel --update`.
Optionally, you can specify a specific channel *generation* number to restore.
{{#include ./opt-common.md}}

View File

@@ -48,14 +48,12 @@ Instead, it looks in a few locations, and acts on all profiles it finds there:
These options are for deleting old [profiles] prior to deleting unreachable [store objects].
- <span id="opt-delete-old">[`--delete-old`](#opt-delete-old)</span> / `-d`
- <span id="opt-delete-old">[`--delete-old`](#opt-delete-old)</span> / `-d`\
Delete all old generations of profiles.
This is the equivalent of invoking [`nix-env --delete-generations old`](@docroot@/command-ref/nix-env/delete-generations.md#generations-old) on each found profile.
- <span id="opt-delete-older-than">[`--delete-older-than`](#opt-delete-older-than)</span> *period*
- <span id="opt-delete-older-than">[`--delete-older-than`](#opt-delete-older-than)</span> *period*\
Delete all generations of profiles older than the specified amount (except for the generations that were active at that point in time).
*period* is a value such as `30d`, which would mean 30 days.

View File

@@ -27,38 +27,38 @@ When using public key authentication, you can avoid typing the passphrase with `
# Options
- `--to`
- `--to`
Copy the closure of _paths_ from a Nix store accessible from the local machine to the Nix store on the remote _machine_.
This is the default behavior.
Copy the closure of _paths_ from a Nix store accessible from the local machine to the Nix store on the remote _machine_.
This is the default behavior.
- `--from`
- `--from`
Copy the closure of _paths_ from the Nix store on the remote _machine_ to the local machine's specified Nix store.
Copy the closure of _paths_ from the Nix store on the remote _machine_ to the local machine's specified Nix store.
- `--gzip`
- `--gzip`
Enable compression of the SSH connection.
Enable compression of the SSH connection.
- `--include-outputs`
- `--include-outputs`
Also copy the outputs of [store derivation]s included in the closure.
Also copy the outputs of [store derivation]s included in the closure.
[store derivation]: @docroot@/glossary.md#gloss-store-derivation
[store derivation]: @docroot@/glossary.md#gloss-store-derivation
- `--use-substitutes` / `-s`
- `--use-substitutes` / `-s`
Attempt to download missing store objects on the target from [substituters](@docroot@/command-ref/conf-file.md#conf-substituters).
Any store objects that cannot be substituted on the target are still copied normally from the source.
This is useful, for instance, if the connection between the source and target machine is slow, but the connection between the target machine and `cache.nixos.org` (the default binary cache server) is fast.
Attempt to download missing store objects on the target from [substituters](@docroot@/command-ref/conf-file.md#conf-substituters).
Any store objects that cannot be substituted on the target are still copied normally from the source.
This is useful, for instance, if the connection between the source and target machine is slow, but the connection between the target machine and `cache.nixos.org` (the default binary cache server) is fast.
{{#include ./opt-common.md}}
# Environment variables
- `NIX_SSHOPTS`
- `NIX_SSHOPTS`
Additional options to be passed to `ssh` on the command line.
Additional options to be passed to `ssh` on the command line.
{{#include ./env-common.md}}

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@@ -12,8 +12,7 @@ This operation deletes the specified generations of the current profile.
*generations* can be a one of the following:
- <span id="generations-list">[`<number>...`](#generations-list)</span>
- <span id="generations-list">[`<number>...`](#generations-list)</span>:\
A list of generation numbers, each one a separate command-line argument.
Delete exactly the profile generations given by their generation number.
@@ -31,8 +30,7 @@ This operation deletes the specified generations of the current profile.
> Because one can roll back to a previous generation, it is possible to have generations newer than the current one.
> They will also be deleted.
- <span id="generations-time">[`<number>d`](#generations-time)</span>
- <span id="generations-time">[`<number>d`](#generations-time)</span>:\
The last *number* days
*Example*: `30d`
@@ -40,8 +38,7 @@ This operation deletes the specified generations of the current profile.
Delete all generations created more than *number* days ago, except the most recent one of them.
This allows rolling back to generations that were available within the specified period.
- <span id="generations-count">[`+<number>`](#generations-count)</span>
- <span id="generations-count">[`+<number>`](#generations-count)</span>:\
The last *number* generations up to the present
*Example*: `+5`

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@@ -1,7 +1,6 @@
# Environment variables
- `NIX_PROFILE`
- `NIX_PROFILE`\
Location of the Nix profile. Defaults to the target of the symlink
`~/.nix-profile`, if it exists, or `/nix/var/nix/profiles/default`
otherwise.

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@@ -21,125 +21,125 @@ It is based on the current generation of the active [profile](@docroot@/command-
The arguments *args* map to store paths in a number of possible ways:
- By default, *args* is a set of [derivation] names denoting derivations in the [default Nix expression].
These are [realised], and the resulting output paths are installed.
Currently installed derivations with a name equal to the name of a derivation being added are removed unless the option `--preserve-installed` is specified.
- By default, *args* is a set of [derivation] names denoting derivations in the [default Nix expression].
These are [realised], and the resulting output paths are installed.
Currently installed derivations with a name equal to the name of a derivation being added are removed unless the option `--preserve-installed` is specified.
[derivation]: @docroot@/glossary.md#gloss-derivation
[default Nix expression]: @docroot@/command-ref/files/default-nix-expression.md
[realised]: @docroot@/glossary.md#gloss-realise
[derivation]: @docroot@/glossary.md#gloss-derivation
[default Nix expression]: @docroot@/command-ref/files/default-nix-expression.md
[realised]: @docroot@/glossary.md#gloss-realise
If there are multiple derivations matching a name in *args* that
have the same name (e.g., `gcc-3.3.6` and `gcc-4.1.1`), then the
derivation with the highest *priority* is used. A derivation can
define a priority by declaring the `meta.priority` attribute. This
attribute should be a number, with a higher value denoting a lower
priority. The default priority is `5`.
If there are multiple derivations matching a name in *args* that
have the same name (e.g., `gcc-3.3.6` and `gcc-4.1.1`), then the
derivation with the highest *priority* is used. A derivation can
define a priority by declaring the `meta.priority` attribute. This
attribute should be a number, with a higher value denoting a lower
priority. The default priority is `5`.
If there are multiple matching derivations with the same priority,
then the derivation with the highest version will be installed.
If there are multiple matching derivations with the same priority,
then the derivation with the highest version will be installed.
You can force the installation of multiple derivations with the same
name by being specific about the versions. For instance, `nix-env --install
gcc-3.3.6 gcc-4.1.1` will install both version of GCC (and will
probably cause a user environment conflict\!).
You can force the installation of multiple derivations with the same
name by being specific about the versions. For instance, `nix-env --install
gcc-3.3.6 gcc-4.1.1` will install both version of GCC (and will
probably cause a user environment conflict\!).
- If [`--attr`](#opt-attr) / `-A` is specified, the arguments are *attribute paths* that select attributes from the [default Nix expression].
This is faster than using derivation names and unambiguous.
Show the attribute paths of available packages with [`nix-env --query`](./query.md):
- If [`--attr`](#opt-attr) / `-A` is specified, the arguments are *attribute paths* that select attributes from the [default Nix expression].
This is faster than using derivation names and unambiguous.
Show the attribute paths of available packages with [`nix-env --query`](./query.md):
```console
nix-env --query --available --attr-path
```
```console
nix-env --query --available --attr-path
```
- If `--from-profile` *path* is given, *args* is a set of names
denoting installed [store paths] in the profile *path*. This is an
easy way to copy user environment elements from one profile to
another.
- If `--from-profile` *path* is given, *args* is a set of names
denoting installed [store paths] in the profile *path*. This is an
easy way to copy user environment elements from one profile to
another.
- If `--from-expression` is given, *args* are [Nix language functions](@docroot@/language/syntax.md#functions) that are called with the [default Nix expression] as their single argument.
The derivations returned by those function calls are installed.
This allows derivations to be specified in an unambiguous way, which is necessary if there are multiple derivations with the same name.
- If `--from-expression` is given, *args* are [Nix language functions](@docroot@/language/constructs.md#functions) that are called with the [default Nix expression] as their single argument.
The derivations returned by those function calls are installed.
This allows derivations to be specified in an unambiguous way, which is necessary if there are multiple derivations with the same name.
- If *args* are [store derivations](@docroot@/glossary.md#gloss-store-derivation), then these are [realised], and the resulting output paths are installed.
- If *args* are [store derivations](@docroot@/glossary.md#gloss-store-derivation), then these are [realised], and the resulting output paths are installed.
- If *args* are [store paths] that are not store derivations, then these are [realised] and installed.
- If *args* are [store paths] that are not store derivations, then these are [realised] and installed.
- By default all [outputs](@docroot@/language/derivations.md#attr-outputs) are installed for each [derivation].
This can be overridden by adding a `meta.outputsToInstall` attribute on the derivation listing a subset of the output names.
- By default all [outputs](@docroot@/language/derivations.md#attr-outputs) are installed for each [derivation].
This can be overridden by adding a `meta.outputsToInstall` attribute on the derivation listing a subset of the output names.
Example:
Example:
The file `example.nix` defines a derivation with two outputs `foo` and `bar`, each containing a file.
The file `example.nix` defines a derivation with two outputs `foo` and `bar`, each containing a file.
```nix
# example.nix
let
pkgs = import <nixpkgs> {};
command = ''
${pkgs.coreutils}/bin/mkdir -p $foo $bar
echo foo > $foo/foo-file
echo bar > $bar/bar-file
'';
in
derivation {
name = "example";
builder = "${pkgs.bash}/bin/bash";
args = [ "-c" command ];
outputs = [ "foo" "bar" ];
system = builtins.currentSystem;
}
```
```nix
# example.nix
let
pkgs = import <nixpkgs> {};
command = ''
${pkgs.coreutils}/bin/mkdir -p $foo $bar
echo foo > $foo/foo-file
echo bar > $bar/bar-file
'';
in
derivation {
name = "example";
builder = "${pkgs.bash}/bin/bash";
args = [ "-c" command ];
outputs = [ "foo" "bar" ];
system = builtins.currentSystem;
}
```
Installing from this Nix expression will make files from both outputs appear in the current profile.
Installing from this Nix expression will make files from both outputs appear in the current profile.
```console
$ nix-env --install --file example.nix
installing 'example'
$ ls ~/.nix-profile
foo-file
bar-file
manifest.nix
```
```console
$ nix-env --install --file example.nix
installing 'example'
$ ls ~/.nix-profile
foo-file
bar-file
manifest.nix
```
Adding `meta.outputsToInstall` to that derivation will make `nix-env` only install files from the specified outputs.
Adding `meta.outputsToInstall` to that derivation will make `nix-env` only install files from the specified outputs.
```nix
# example-outputs.nix
import ./example.nix // { meta.outputsToInstall = [ "bar" ]; }
```
```nix
# example-outputs.nix
import ./example.nix // { meta.outputsToInstall = [ "bar" ]; }
```
```console
$ nix-env --install --file example-outputs.nix
installing 'example'
$ ls ~/.nix-profile
bar-file
manifest.nix
```
```console
$ nix-env --install --file example-outputs.nix
installing 'example'
$ ls ~/.nix-profile
bar-file
manifest.nix
```
# Options
- `--prebuilt-only` / `-b`
- `--prebuilt-only` / `-b`
Use only derivations for which a substitute is registered, i.e.,
there is a pre-built binary available that can be downloaded in lieu
of building the derivation. Thus, no packages will be built from
source.
Use only derivations for which a substitute is registered, i.e.,
there is a pre-built binary available that can be downloaded in lieu
of building the derivation. Thus, no packages will be built from
source.
- `--preserve-installed` / `-P`
- `--preserve-installed` / `-P`
Do not remove derivations with a name matching one of the
derivations being installed. Usually, trying to have two versions of
the same package installed in the same generation of a profile will
lead to an error in building the generation, due to file name
clashes between the two versions. However, this is not the case for
all packages.
Do not remove derivations with a name matching one of the
derivations being installed. Usually, trying to have two versions of
the same package installed in the same generation of a profile will
lead to an error in building the generation, due to file name
clashes between the two versions. However, this is not the case for
all packages.
- `--remove-all` / `-r`
- `--remove-all` / `-r`
Remove all previously installed packages first. This is equivalent
to running `nix-env --uninstall '.*'` first, except that everything happens
in a single transaction.
Remove all previously installed packages first. This is equivalent
to running `nix-env --uninstall '.*'` first, except that everything happens
in a single transaction.
{{#include ./opt-common.md}}

View File

@@ -2,37 +2,34 @@
The following options are allowed for all `nix-env` operations, but may not always have an effect.
- `--file` / `-f` *path*
- `--file` / `-f` *path*\
Specifies the Nix expression (designated below as the *active Nix
expression*) used by the `--install`, `--upgrade`, and `--query
--available` operations to obtain derivations. The default is
`~/.nix-defexpr`.
Specifies the Nix expression (designated below as the *active Nix
expression*) used by the `--install`, `--upgrade`, and `--query
--available` operations to obtain derivations. The default is
`~/.nix-defexpr`.
If the argument starts with `http://` or `https://`, it is
interpreted as the URL of a tarball that will be downloaded and
unpacked to a temporary location. The tarball must include a single
top-level directory containing at least a file named `default.nix`.
If the argument starts with `http://` or `https://`, it is
interpreted as the URL of a tarball that will be downloaded and
unpacked to a temporary location. The tarball must include a single
top-level directory containing at least a file named `default.nix`.
- `--profile` / `-p` *path*\
Specifies the profile to be used by those operations that operate on
a profile (designated below as the *active profile*). A profile is a
sequence of user environments called *generations*, one of which is
the *current generation*.
- `--profile` / `-p` *path*
- `--dry-run`\
For the `--install`, `--upgrade`, `--uninstall`,
`--switch-generation`, `--delete-generations` and `--rollback`
operations, this flag will cause `nix-env` to print what *would* be
done if this flag had not been specified, without actually doing it.
Specifies the profile to be used by those operations that operate on
a profile (designated below as the *active profile*). A profile is a
sequence of user environments called *generations*, one of which is
the *current generation*.
`--dry-run` also prints out which paths will be
[substituted](@docroot@/glossary.md) (i.e., downloaded) and which paths
will be built from source (because no substitute is available).
- `--dry-run`
For the `--install`, `--upgrade`, `--uninstall`,
`--switch-generation`, `--delete-generations` and `--rollback`
operations, this flag will cause `nix-env` to print what *would* be
done if this flag had not been specified, without actually doing it.
`--dry-run` also prints out which paths will be
[substituted](@docroot@/glossary.md) (i.e., downloaded) and which paths
will be built from source (because no substitute is available).
- `--system-filter` *system*
By default, operations such as `--query --available` show derivations matching any platform. This option
allows you to use derivations for the specified platform *system*.
- `--system-filter` *system*\
By default, operations such as `--query
--available` show derivations matching any platform. This option
allows you to use derivations for the specified platform *system*.

View File

@@ -35,13 +35,11 @@ The derivations are sorted by their `name` attributes.
The following flags specify the set of things on which the query
operates.
- `--installed`
- `--installed`\
The query operates on the store paths that are installed in the
current generation of the active profile. This is the default.
- `--available` / `-a`
- `--available`; `-a`\
The query operates on the derivations that are available in the
active Nix expression.
@@ -52,28 +50,24 @@ selected derivations. Multiple flags may be specified, in which case the
information is shown in the order given here. Note that the name of the
derivation is shown unless `--no-name` is specified.
- `--xml`
- `--xml`\
Print the result in an XML representation suitable for automatic
processing by other tools. The root element is called `items`, which
contains a `item` element for each available or installed
derivation. The fields discussed below are all stored in attributes
of the `item` elements.
- `--json`
- `--json`\
Print the result in a JSON representation suitable for automatic
processing by other tools.
- `--prebuilt-only` / `-b`
- `--prebuilt-only` / `-b`\
Show only derivations for which a substitute is registered, i.e.,
there is a pre-built binary available that can be downloaded in lieu
of building the derivation. Thus, this shows all packages that
probably can be installed quickly.
- `--status` / `-s`
- `--status`; `-s`\
Print the *status* of the derivation. The status consists of three
characters. The first is `I` or `-`, indicating whether the
derivation is currently installed in the current generation of the
@@ -84,61 +78,49 @@ derivation is shown unless `--no-name` is specified.
derivation to be built. The third is `S` or `-`, indicating whether
a substitute is available for the derivation.
- `--attr-path` / `-P`
- `--attr-path`; `-P`\
Print the *attribute path* of the derivation, which can be used to
unambiguously select it using the `--attr` option available in
commands that install derivations like `nix-env --install`. This
option only works together with `--available`
- `--no-name`
- `--no-name`\
Suppress printing of the `name` attribute of each derivation.
- `--compare-versions` / `-c`
- `--compare-versions` / `-c`\
Compare installed versions to available versions, or vice versa (if
`--available` is given). This is useful for quickly seeing whether
upgrades for installed packages are available in a Nix expression. A
column is added with the following meaning:
- `<` *version*
- `<` *version*\
A newer version of the package is available or installed.
- `=` *version*
- `=` *version*\
At most the same version of the package is available or
installed.
- `>` *version*
- `>` *version*\
Only older versions of the package are available or installed.
- `- ?`
- `- ?`\
No version of the package is available or installed.
- `--system`
- `--system`\
Print the `system` attribute of the derivation.
- `--drv-path`
- `--drv-path`\
Print the path of the [store derivation](@docroot@/glossary.md#gloss-store-derivation).
- `--out-path`
- `--out-path`\
Print the output path of the derivation.
- `--description`
- `--description`\
Print a short (one-line) description of the derivation, if
available. The description is taken from the `meta.description`
attribute of the derivation.
- `--meta`
- `--meta`\
Print all of the meta-attributes of the derivation. This option is
only available with `--xml` or `--json`.

View File

@@ -13,24 +13,24 @@ to be modified. There are several attributes that can be usefully
modified, because they affect the behaviour of `nix-env` or the user
environment build script:
- `priority` can be changed to resolve filename clashes. The user
environment build script uses the `meta.priority` attribute of
derivations to resolve filename collisions between packages. Lower
priority values denote a higher priority. For instance, the GCC
wrapper package and the Binutils package in Nixpkgs both have a file
`bin/ld`, so previously if you tried to install both you would get a
collision. Now, on the other hand, the GCC wrapper declares a higher
priority than Binutils, so the formers `bin/ld` is symlinked in the
user environment.
- `priority` can be changed to resolve filename clashes. The user
environment build script uses the `meta.priority` attribute of
derivations to resolve filename collisions between packages. Lower
priority values denote a higher priority. For instance, the GCC
wrapper package and the Binutils package in Nixpkgs both have a file
`bin/ld`, so previously if you tried to install both you would get a
collision. Now, on the other hand, the GCC wrapper declares a higher
priority than Binutils, so the formers `bin/ld` is symlinked in the
user environment.
- `keep` can be set to `true` to prevent the package from being
upgraded or replaced. This is useful if you want to hang on to an
older version of a package.
- `keep` can be set to `true` to prevent the package from being
upgraded or replaced. This is useful if you want to hang on to an
older version of a package.
- `active` can be set to `false` to “disable” the package. That is, no
symlinks will be generated to the files of the package, but it
remains part of the profile (so it wont be garbage-collected). It
can be set back to `true` to re-enable the package.
- `active` can be set to `false` to “disable” the package. That is, no
symlinks will be generated to the files of the package, but it
remains part of the profile (so it wont be garbage-collected). It
can be set back to `true` to re-enable the package.
{{#include ./opt-common.md}}

View File

@@ -28,48 +28,42 @@ version is installed.
# Flags
- `--lt`
- `--lt`\
Only upgrade a derivation to newer versions. This is the default.
Only upgrade a derivation to newer versions. This is the default.
- `--leq`\
In addition to upgrading to newer versions, also “upgrade” to
derivations that have the same version. Version are not a unique
identification of a derivation, so there may be many derivations
that have the same version. This flag may be useful to force
“synchronisation” between the installed and available derivations.
- `--leq`
- `--eq`\
*Only* “upgrade” to derivations that have the same version. This may
not seem very useful, but it actually is, e.g., when there is a new
release of Nixpkgs and you want to replace installed applications
with the same versions built against newer dependencies (to reduce
the number of dependencies floating around on your system).
In addition to upgrading to newer versions, also “upgrade” to
derivations that have the same version. Version are not a unique
identification of a derivation, so there may be many derivations
that have the same version. This flag may be useful to force
“synchronisation” between the installed and available derivations.
- `--always`\
In addition to upgrading to newer versions, also “upgrade” to
derivations that have the same or a lower version. I.e., derivations
may actually be downgraded depending on what is available in the
active Nix expression.
- `--eq`
- `--prebuilt-only` / `-b`\
Use only derivations for which a substitute is registered, i.e.,
there is a pre-built binary available that can be downloaded in lieu
of building the derivation. Thus, no packages will be built from
source.
*Only* “upgrade” to derivations that have the same version. This may
not seem very useful, but it actually is, e.g., when there is a new
release of Nixpkgs and you want to replace installed applications
with the same versions built against newer dependencies (to reduce
the number of dependencies floating around on your system).
- `--always`
In addition to upgrading to newer versions, also “upgrade” to
derivations that have the same or a lower version. I.e., derivations
may actually be downgraded depending on what is available in the
active Nix expression.
- `--prebuilt-only` / `-b`
Use only derivations for which a substitute is registered, i.e.,
there is a pre-built binary available that can be downloaded in lieu
of building the derivation. Thus, no packages will be built from
source.
- `--preserve-installed` / `-P`
Do not remove derivations with a name matching one of the
derivations being installed. Usually, trying to have two versions of
the same package installed in the same generation of a profile will
lead to an error in building the generation, due to file name
clashes between the two versions. However, this is not the case for
all packages.
- `--preserve-installed` / `-P`\
Do not remove derivations with a name matching one of the
derivations being installed. Usually, trying to have two versions of
the same package installed in the same generation of a profile will
lead to an error in building the generation, due to file name
clashes between the two versions. However, this is not the case for
all packages.
{{#include ./opt-common.md}}

View File

@@ -29,65 +29,54 @@ md5sum`.
# Options
- `--flat`
- `--flat`\
Print the cryptographic hash of the contents of each regular file *path*.
That is, instead of computing
the hash of the [Nix Archive (NAR)](@docroot@/store/file-system-object/content-address.md#serial-nix-archive) of *path*,
just [directly hash]((@docroot@/store/file-system-object/content-address.md#serial-flat) *path* as is.
This requires *path* to resolve to a regular file rather than directory.
The result is identical to that produced by the GNU commands
`md5sum` and `sha1sum`.
Print the cryptographic hash of the contents of each regular file *path*.
That is, instead of computing
the hash of the [Nix Archive (NAR)](@docroot@/store/file-system-object/content-address.md#serial-nix-archive) of *path*,
just [directly hash]((@docroot@/store/file-system-object/content-address.md#serial-flat) *path* as is.
This requires *path* to resolve to a regular file rather than directory.
The result is identical to that produced by the GNU commands
`md5sum` and `sha1sum`.
- `--base16`\
Print the hash in a hexadecimal representation (default).
- `--base16`
- `--base32`\
Print the hash in a base-32 representation rather than hexadecimal.
This base-32 representation is more compact and can be used in Nix
expressions (such as in calls to `fetchurl`).
Print the hash in a hexadecimal representation (default).
- `--base64`\
Similar to --base32, but print the hash in a base-64 representation,
which is more compact than the base-32 one.
- `--base32`
- `--sri`\
Print the hash in SRI format with base-64 encoding.
The type of hash algorithm will be prepended to the hash string,
followed by a hyphen (-) and the base-64 hash body.
Print the hash in a base-32 representation rather than hexadecimal.
This base-32 representation is more compact and can be used in Nix
expressions (such as in calls to `fetchurl`).
- `--truncate`\
Truncate hashes longer than 160 bits (such as SHA-256) to 160 bits.
- `--base64`
- `--type` *hashAlgo*\
Use the specified cryptographic hash algorithm, which can be one of
`md5`, `sha1`, `sha256`, and `sha512`.
Similar to --base32, but print the hash in a base-64 representation,
which is more compact than the base-32 one.
- `--to-base16`\
Dont hash anything, but convert the base-32 hash representation
*hash* to hexadecimal.
- `--sri`
- `--to-base32`\
Dont hash anything, but convert the hexadecimal hash representation
*hash* to base-32.
Print the hash in SRI format with base-64 encoding.
The type of hash algorithm will be prepended to the hash string,
followed by a hyphen (-) and the base-64 hash body.
- `--to-base64`\
Dont hash anything, but convert the hexadecimal hash representation
*hash* to base-64.
- `--truncate`
Truncate hashes longer than 160 bits (such as SHA-256) to 160 bits.
- `--type` *hashAlgo*
Use the specified cryptographic hash algorithm, which can be one of
`md5`, `sha1`, `sha256`, and `sha512`.
- `--to-base16`
Dont hash anything, but convert the base-32 hash representation
*hash* to hexadecimal.
- `--to-base32`
Dont hash anything, but convert the hexadecimal hash representation
*hash* to base-32.
- `--to-base64`
Dont hash anything, but convert the hexadecimal hash representation
*hash* to base-64.
- `--to-sri`
Dont hash anything, but convert the hexadecimal hash representation
*hash* to SRI.
- `--to-sri`\
Dont hash anything, but convert the hexadecimal hash representation
*hash* to SRI.
# Examples

View File

@@ -30,97 +30,89 @@ standard input.
# Options
- `--add-root` *path*
- `--add-root` *path*\
See the [corresponding option](nix-store.md) in `nix-store`.
See the [corresponding option](nix-store.md) in `nix-store`.
- `--parse`\
Just parse the input files, and print their abstract syntax trees on
standard output as a Nix expression.
- `--parse`
- `--eval`\
Just parse and evaluate the input files, and print the resulting
values on standard output. No instantiation of store derivations
takes place.
Just parse the input files, and print their abstract syntax trees on
standard output as a Nix expression.
> **Warning**
>
> This option produces output which can be parsed as a Nix expression which
> will produce a different result than the input expression when evaluated.
> For example, these two Nix expressions print the same result despite
> having different meaning:
>
> ```console
> $ nix-instantiate --eval --expr '{ a = {}; }'
> { a = <CODE>; }
> $ nix-instantiate --eval --expr '{ a = <CODE>; }'
> { a = <CODE>; }
> ```
>
> For human-readable output, `nix eval` (experimental) is more informative:
>
> ```console
> $ nix-instantiate --eval --expr 'a: a'
> <LAMBDA>
> $ nix eval --expr 'a: a'
> «lambda @ «string»:1:1»
> ```
>
> For machine-readable output, the `--xml` option produces unambiguous
> output:
>
> ```console
> $ nix-instantiate --eval --xml --expr '{ foo = <CODE>; }'
> <?xml version='1.0' encoding='utf-8'?>
> <expr>
> <attrs>
> <attr column="3" line="1" name="foo">
> <unevaluated />
> </attr>
> </attrs>
> </expr>
> ```
- `--eval`
- `--find-file`\
Look up the given files in Nixs search path (as specified by the
`NIX_PATH` environment variable). If found, print the corresponding
absolute paths on standard output. For instance, if `NIX_PATH` is
`nixpkgs=/home/alice/nixpkgs`, then `nix-instantiate --find-file
nixpkgs/default.nix` will print `/home/alice/nixpkgs/default.nix`.
Just parse and evaluate the input files, and print the resulting
values on standard output. No instantiation of store derivations
takes place.
- `--strict`\
When used with `--eval`, recursively evaluate list elements and
attributes. Normally, such sub-expressions are left unevaluated
(since the Nix language is lazy).
> **Warning**
>
> This option produces output which can be parsed as a Nix expression which
> will produce a different result than the input expression when evaluated.
> For example, these two Nix expressions print the same result despite
> having different meaning:
>
> ```console
> $ nix-instantiate --eval --expr '{ a = {}; }'
> { a = <CODE>; }
> $ nix-instantiate --eval --expr '{ a = <CODE>; }'
> { a = <CODE>; }
> ```
>
> For human-readable output, `nix eval` (experimental) is more informative:
>
> ```console
> $ nix-instantiate --eval --expr 'a: a'
> <LAMBDA>
> $ nix eval --expr 'a: a'
> «lambda @ «string»:1:1»
> ```
>
> For machine-readable output, the `--xml` option produces unambiguous
> output:
>
> ```console
> $ nix-instantiate --eval --xml --expr '{ foo = <CODE>; }'
> <?xml version='1.0' encoding='utf-8'?>
> <expr>
> <attrs>
> <attr column="3" line="1" name="foo">
> <unevaluated />
> </attr>
> </attrs>
> </expr>
> ```
> **Warning**
>
> This option can cause non-termination, because lazy data
> structures can be infinitely large.
- `--find-file`
- `--json`\
When used with `--eval`, print the resulting value as an JSON
representation of the abstract syntax tree rather than as a Nix expression.
Look up the given files in Nixs search path (as specified by the
`NIX_PATH` environment variable). If found, print the corresponding
absolute paths on standard output. For instance, if `NIX_PATH` is
`nixpkgs=/home/alice/nixpkgs`, then `nix-instantiate --find-file
nixpkgs/default.nix` will print `/home/alice/nixpkgs/default.nix`.
- `--xml`\
When used with `--eval`, print the resulting value as an XML
representation of the abstract syntax tree rather than as a Nix expression.
The schema is the same as that used by the [`toXML`
built-in](../language/builtins.md).
- `--strict`
When used with `--eval`, recursively evaluate list elements and
attributes. Normally, such sub-expressions are left unevaluated
(since the Nix language is lazy).
> **Warning**
>
> This option can cause non-termination, because lazy data
> structures can be infinitely large.
- `--json`
When used with `--eval`, print the resulting value as an JSON
representation of the abstract syntax tree rather than as a Nix expression.
- `--xml`
When used with `--eval`, print the resulting value as an XML
representation of the abstract syntax tree rather than as a Nix expression.
The schema is the same as that used by the [`toXML`
built-in](../language/builtins.md).
- `--read-write-mode`
When used with `--eval`, perform evaluation in read/write mode so
nix language features that require it will still work (at the cost
of needing to do instantiation of every evaluated derivation). If
this option is not enabled, there may be uninstantiated store paths
in the final output.
- `--read-write-mode`\
When used with `--eval`, perform evaluation in read/write mode so
nix language features that require it will still work (at the cost
of needing to do instantiation of every evaluated derivation). If
this option is not enabled, there may be uninstantiated store paths
in the final output.
{{#include ./opt-common.md}}

View File

@@ -39,32 +39,27 @@ the path of the downloaded file in the Nix store is also printed.
# Options
- `--type` *hashAlgo*
- `--type` *hashAlgo*\
Use the specified cryptographic hash algorithm,
which can be one of `md5`, `sha1`, `sha256`, and `sha512`.
The default is `sha256`.
Use the specified cryptographic hash algorithm,
which can be one of `md5`, `sha1`, `sha256`, and `sha512`.
The default is `sha256`.
- `--print-path`\
Print the store path of the downloaded file on standard output.
- `--print-path`
- `--unpack`\
Unpack the archive (which must be a tarball or zip file) and add the
result to the Nix store. The resulting hash can be used with
functions such as Nixpkgss `fetchzip` or `fetchFromGitHub`.
Print the store path of the downloaded file on standard output.
- `--executable`\
Set the executable bit on the downloaded file.
- `--unpack`
Unpack the archive (which must be a tarball or zip file) and add the
result to the Nix store. The resulting hash can be used with
functions such as Nixpkgss `fetchzip` or `fetchFromGitHub`.
- `--executable`
Set the executable bit on the downloaded file.
- `--name` *name*
Override the name of the file in the Nix store. By default, this is
`hash-basename`, where *basename* is the last component of *url*.
Overriding the name is necessary when *basename* contains characters
that are not allowed in Nix store paths.
- `--name` *name*\
Override the name of the file in the Nix store. By default, this is
`hash-basename`, where *basename* is the last component of *url*.
Overriding the name is necessary when *basename* contains characters
that are not allowed in Nix store paths.
# Examples

View File

@@ -60,63 +60,55 @@ All options not listed here are passed to `nix-store
--realise`, except for `--arg` and `--attr` / `-A` which are passed to
`nix-instantiate`.
- `--command` *cmd*
- `--command` *cmd*\
In the environment of the derivation, run the shell command *cmd*.
This command is executed in an interactive shell. (Use `--run` to
use a non-interactive shell instead.) However, a call to `exit` is
implicitly added to the command, so the shell will exit after
running the command. To prevent this, add `return` at the end;
e.g. `--command "echo Hello; return"` will print `Hello` and then
drop you into the interactive shell. This can be useful for doing
any additional initialisation.
In the environment of the derivation, run the shell command *cmd*.
This command is executed in an interactive shell. (Use `--run` to
use a non-interactive shell instead.) However, a call to `exit` is
implicitly added to the command, so the shell will exit after
running the command. To prevent this, add `return` at the end;
e.g. `--command "echo Hello; return"` will print `Hello` and then
drop you into the interactive shell. This can be useful for doing
any additional initialisation.
- `--run` *cmd*\
Like `--command`, but executes the command in a non-interactive
shell. This means (among other things) that if you hit Ctrl-C while
the command is running, the shell exits.
- `--run` *cmd*
- `--exclude` *regexp*\
Do not build any dependencies whose store path matches the regular
expression *regexp*. This option may be specified multiple times.
Like `--command`, but executes the command in a non-interactive
shell. This means (among other things) that if you hit Ctrl-C while
the command is running, the shell exits.
- `--pure`\
If this flag is specified, the environment is almost entirely
cleared before the interactive shell is started, so you get an
environment that more closely corresponds to the “real” Nix build. A
few variables, in particular `HOME`, `USER` and `DISPLAY`, are
retained.
- `--exclude` *regexp*
- `--packages` / `-p` *packages*…\
Set up an environment in which the specified packages are present.
The command line arguments are interpreted as attribute names inside
the Nix Packages collection. Thus, `nix-shell --packages libjpeg openjdk`
will start a shell in which the packages denoted by the attribute
names `libjpeg` and `openjdk` are present.
Do not build any dependencies whose store path matches the regular
expression *regexp*. This option may be specified multiple times.
- `-i` *interpreter*\
The chained script interpreter to be invoked by `nix-shell`. Only
applicable in `#!`-scripts (described below).
- `--pure`
If this flag is specified, the environment is almost entirely
cleared before the interactive shell is started, so you get an
environment that more closely corresponds to the “real” Nix build. A
few variables, in particular `HOME`, `USER` and `DISPLAY`, are
retained.
- `--packages` / `-p` *packages*
Set up an environment in which the specified packages are present.
The command line arguments are interpreted as attribute names inside
the Nix Packages collection. Thus, `nix-shell --packages libjpeg openjdk`
will start a shell in which the packages denoted by the attribute
names `libjpeg` and `openjdk` are present.
- `-i` *interpreter*
The chained script interpreter to be invoked by `nix-shell`. Only
applicable in `#!`-scripts (described below).
- `--keep` *name*
When a `--pure` shell is started, keep the listed environment
variables.
- `--keep` *name*\
When a `--pure` shell is started, keep the listed environment
variables.
{{#include ./opt-common.md}}
# Environment variables
- `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.
- `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.
{{#include ./env-common.md}}
@@ -210,14 +202,14 @@ For example, here is a Python script that depends on Python and the
```python
#! /usr/bin/env nix-shell
#! nix-shell -i python3 --packages python3 python3Packages.prettytable
#! nix-shell -i python --packages python pythonPackages.prettytable
import prettytable
# Print a simple table.
t = prettytable.PrettyTable(["N", "N^2"])
for n in range(1, 10): t.add_row([n, n * n])
print(t)
print t
```
Similarly, the following is a Perl script that specifies that it
@@ -297,8 +289,3 @@ with import <nixpkgs> {};
runCommand "dummy" { buildInputs = [ python pythonPackages.prettytable ]; } ""
```
The script's file name is passed as the first argument to the interpreter specified by the `-i` flag.
Aside from the very first line, which is a directive to the operating system, the additional `#! nix-shell` lines do not need to be at the beginning of the file.
This allows wrapping them in block comments for languages where `#` does not start a comment, such as ECMAScript, Erlang, PHP, or Ruby.

View File

@@ -16,10 +16,9 @@ public url or broke since the download expression was written.
This operation has the following options:
- `--recursive`
Use recursive instead of flat hashing mode, used when adding
directories to the store.
- `--recursive`\
Use recursive instead of flat hashing mode, used when adding
directories to the store.
{{#include ./opt-common.md}}

View File

@@ -14,34 +14,30 @@ reachable via file system references from a set of “roots”, are deleted.
The following suboperations may be specified:
- `--print-roots`
- `--print-roots`\
This operation prints on standard output the set of roots used by
the garbage collector.
This operation prints on standard output the set of roots used by
the garbage collector.
- `--print-live`\
This operation prints on standard output the set of “live” store
paths, which are all the store paths reachable from the roots. Live
paths should never be deleted, since that would break consistency —
it would become possible that applications are installed that
reference things that are no longer present in the store.
- `--print-live`
This operation prints on standard output the set of live” store
paths, which are all the store paths reachable from the roots. Live
paths should never be deleted, since that would break consistency —
it would become possible that applications are installed that
reference things that are no longer present in the store.
- `--print-dead`
This operation prints out on standard output the set of “dead” store
paths, which is just the opposite of the set of live paths: any path
in the store that is not live (with respect to the roots) is dead.
- `--print-dead`\
This operation prints out on standard output the set of “dead” store
paths, which is just the opposite of the set of live paths: any path
in the store that is not live (with respect to the roots) is dead.
By default, all unreachable paths are deleted. The following options
control what gets deleted and in what order:
- `--max-freed` *bytes*
Keep deleting paths until at least *bytes* bytes have been deleted,
then stop. The argument *bytes* can be followed by the
multiplicative suffix `K`, `M`, `G` or `T`, denoting KiB, MiB, GiB
or TiB units.
- `--max-freed` *bytes*\
Keep deleting paths until at least *bytes* bytes have been deleted,
then stop. The argument *bytes* can be followed by the
multiplicative suffix `K`, `M`, `G` or `T`, denoting KiB, MiB, GiB
or TiB units.
The behaviour of the collector is also influenced by the
`keep-outputs` and `keep-derivations` settings in the Nix

View File

@@ -24,138 +24,122 @@ symlink.
# Common query options
- `--use-output` / `-u`
- `--use-output`; `-u`\
For each argument to the query that is a [store derivation], apply the
query to the output path of the derivation instead.
For each argument to the query that is a [store derivation], apply the
query to the output path of the derivation instead.
- `--force-realise` / `-f`
Realise each argument to the query first (see [`nix-store --realise`](./realise.md)).
- `--force-realise`; `-f`\
Realise each argument to the query first (see [`nix-store --realise`](./realise.md)).
[store derivation]: @docroot@/glossary.md#gloss-store-derivation
# Queries
- `--outputs`
- `--outputs`\
Prints out the [output paths] of the store
derivations *paths*. These are the paths that will be produced when
the derivation is built.
Prints out the [output paths] of the store
derivations *paths*. These are the paths that will be produced when
the derivation is built.
[output paths]: @docroot@/glossary.md#gloss-output-path
[output paths]: @docroot@/glossary.md#gloss-output-path
- `--requisites`; `-R`\
Prints out the [closure] of the store path *paths*.
- `--requisites` / `-R`
[closure]: @docroot@/glossary.md#gloss-closure
Prints out the [closure] of the store path *paths*.
This query has one option:
[closure]: @docroot@/glossary.md#gloss-closure
- `--include-outputs`
Also include the existing output paths of [store derivation]s,
and their closures.
This query has one option:
This query can be used to implement various kinds of deployment. A
*source deployment* is obtained by distributing the closure of a
store derivation. A *binary deployment* is obtained by distributing
the closure of an output path. A *cache deployment* (combined
source/binary deployment, including binaries of build-time-only
dependencies) is obtained by distributing the closure of a store
derivation and specifying the option `--include-outputs`.
- `--include-outputs`
Also include the existing output paths of [store derivation]s,
and their closures.
- `--references`\
Prints the set of [references] of the store paths
*paths*, that is, their immediate dependencies. (For *all*
dependencies, use `--requisites`.)
This query can be used to implement various kinds of deployment. A
*source deployment* is obtained by distributing the closure of a
store derivation. A *binary deployment* is obtained by distributing
the closure of an output path. A *cache deployment* (combined
source/binary deployment, including binaries of build-time-only
dependencies) is obtained by distributing the closure of a store
derivation and specifying the option `--include-outputs`.
[references]: @docroot@/glossary.md#gloss-reference
- `--references`
- `--referrers`\
Prints the set of *referrers* of the store paths *paths*, that is,
the store paths currently existing in the Nix store that refer to
one of *paths*. Note that contrary to the references, the set of
referrers is not constant; it can change as store paths are added or
removed.
Prints the set of [references] of the store paths
*paths*, that is, their immediate dependencies. (For *all*
dependencies, use `--requisites`.)
- `--referrers-closure`\
Prints the closure of the set of store paths *paths* under the
referrers relation; that is, all store paths that directly or
indirectly refer to one of *paths*. These are all the path currently
in the Nix store that are dependent on *paths*.
[references]: @docroot@/glossary.md#gloss-reference
- `--deriver`; `-d`\
Prints the [deriver] that was used to build the store paths *paths*. If
the path has no deriver (e.g., if it is a source file), or if the
deriver is not known (e.g., in the case of a binary-only
deployment), the string `unknown-deriver` is printed.
The returned deriver is not guaranteed to exist in the local store, for
example when *paths* were substituted from a binary cache.
Use `--valid-derivers` instead to obtain valid paths only.
- `--referrers`
[deriver]: @docroot@/glossary.md#gloss-deriver
Prints the set of *referrers* of the store paths *paths*, that is,
the store paths currently existing in the Nix store that refer to
one of *paths*. Note that contrary to the references, the set of
referrers is not constant; it can change as store paths are added or
removed.
- `--valid-derivers`\
Prints a set of derivation files (`.drv`) which are supposed produce
said paths when realized. Might print nothing, for example for source paths
or paths subsituted from a binary cache.
- `--referrers-closure`
- `--graph`\
Prints the references graph of the store paths *paths* in the format
of the `dot` tool of AT\&T's [Graphviz
package](http://www.graphviz.org/). This can be used to visualise
dependency graphs. To obtain a build-time dependency graph, apply
this to a store derivation. To obtain a runtime dependency graph,
apply it to an output path.
Prints the closure of the set of store paths *paths* under the
referrers relation; that is, all store paths that directly or
indirectly refer to one of *paths*. These are all the path currently
in the Nix store that are dependent on *paths*.
- `--tree`\
Prints the references graph of the store paths *paths* as a nested
ASCII tree. References are ordered by descending closure size; this
tends to flatten the tree, making it more readable. The query only
recurses into a store path when it is first encountered; this
prevents a blowup of the tree representation of the graph.
- `--deriver` / `-d`
- `--graphml`\
Prints the references graph of the store paths *paths* in the
[GraphML](http://graphml.graphdrawing.org/) file format. This can be
used to visualise dependency graphs. To obtain a build-time
dependency graph, apply this to a [store derivation]. To obtain a
runtime dependency graph, apply it to an output path.
Prints the [deriver] that was used to build the store paths *paths*. If
the path has no deriver (e.g., if it is a source file), or if the
deriver is not known (e.g., in the case of a binary-only
deployment), the string `unknown-deriver` is printed.
The returned deriver is not guaranteed to exist in the local store, for
example when *paths* were substituted from a binary cache.
Use `--valid-derivers` instead to obtain valid paths only.
- `--binding` *name*; `-b` *name*\
Prints the value of the attribute *name* (i.e., environment
variable) of the [store derivation]s *paths*. It is an error for a
derivation to not have the specified attribute.
[deriver]: @docroot@/glossary.md#gloss-deriver
- `--hash`\
Prints the SHA-256 hash of the contents of the store paths *paths*
(that is, the hash of the output of `nix-store --dump` on the given
paths). Since the hash is stored in the Nix database, this is a fast
operation.
- `--valid-derivers`
- `--size`\
Prints the size in bytes of the contents of the store paths *paths*
— to be precise, the size of the output of `nix-store --dump` on
the given paths. Note that the actual disk space required by the
store paths may be higher, especially on filesystems with large
cluster sizes.
Prints a set of derivation files (`.drv`) which are supposed produce
said paths when realized. Might print nothing, for example for source paths
or paths subsituted from a binary cache.
- `--graph`
Prints the references graph of the store paths *paths* in the format
of the `dot` tool of AT\&T's [Graphviz
package](http://www.graphviz.org/). This can be used to visualise
dependency graphs. To obtain a build-time dependency graph, apply
this to a store derivation. To obtain a runtime dependency graph,
apply it to an output path.
- `--tree`
Prints the references graph of the store paths *paths* as a nested
ASCII tree. References are ordered by descending closure size; this
tends to flatten the tree, making it more readable. The query only
recurses into a store path when it is first encountered; this
prevents a blowup of the tree representation of the graph.
- `--graphml`
Prints the references graph of the store paths *paths* in the
[GraphML](http://graphml.graphdrawing.org/) file format. This can be
used to visualise dependency graphs. To obtain a build-time
dependency graph, apply this to a [store derivation]. To obtain a
runtime dependency graph, apply it to an output path.
- `--binding` *name* / `-b` *name*
Prints the value of the attribute *name* (i.e., environment
variable) of the [store derivation]s *paths*. It is an error for a
derivation to not have the specified attribute.
- `--hash`
Prints the SHA-256 hash of the contents of the store paths *paths*
(that is, the hash of the output of `nix-store --dump` on the given
paths). Since the hash is stored in the Nix database, this is a fast
operation.
- `--size`
Prints the size in bytes of the contents of the store paths *paths*
— to be precise, the size of the output of `nix-store --dump` on
the given paths. Note that the actual disk space required by the
store paths may be higher, especially on filesystems with large
cluster sizes.
- `--roots`
Prints the garbage collector roots that point, directly or
indirectly, at the store paths *paths*.
- `--roots`\
Prints the garbage collector roots that point, directly or
indirectly, at the store paths *paths*.
{{#include ./opt-common.md}}

View File

@@ -32,7 +32,7 @@ If no substitutes are available and no store derivation is given, realisation fa
[store objects]: @docroot@/store/store-object.md
[closure]: @docroot@/glossary.md#gloss-closure
[substituters]: @docroot@/command-ref/conf-file.md#conf-substituters
[content-addressed derivations]: @docroot@/development/experimental-features.md#xp-feature-ca-derivations
[content-addressed derivations]: @docroot@/contributing/experimental-features.md#xp-feature-ca-derivations
[Nix database]: @docroot@/glossary.md#gloss-nix-database
The resulting paths are printed on standard output.
@@ -42,26 +42,23 @@ For non-derivation arguments, the argument itself is printed.
# Options
- `--dry-run`
- `--dry-run`\
Print on standard error a description of what packages would be
built or downloaded, without actually performing the operation.
Print on standard error a description of what packages would be
built or downloaded, without actually performing the operation.
- `--ignore-unknown`\
If a non-derivation path does not have a substitute, then silently
ignore it.
- `--ignore-unknown`
If a non-derivation path does not have a substitute, then silently
ignore it.
- `--check`
This option allows you to check whether a derivation is
deterministic. It rebuilds the specified derivation and checks
whether the result is bitwise-identical with the existing outputs,
printing an error if thats not the case. The outputs of the
specified derivation must already exist. When used with `-K`, if an
output path is not identical to the corresponding output from the
previous build, the new output path is left in
`/nix/store/name.check.`
- `--check`\
This option allows you to check whether a derivation is
deterministic. It rebuilds the specified derivation and checks
whether the result is bitwise-identical with the existing outputs,
printing an error if thats not the case. The outputs of the
specified derivation must already exist. When used with `-K`, if an
output path is not identical to the corresponding output from the
previous build, the new output path is left in
`/nix/store/name.check.`
{{#include ./opt-common.md}}

View File

@@ -14,11 +14,10 @@ access to a restricted ssh user.
The following flags are available:
- `--write`
Allow the connected client to request the realization of
derivations. In effect, this can be used to make the host act as a
remote builder.
- `--write`\
Allow the connected client to request the realization of
derivations. In effect, this can be used to make the host act as a
remote builder.
{{#include ./opt-common.md}}

View File

@@ -16,20 +16,18 @@ being modified by non-Nix tools, or of bugs in Nix itself.
This operation has the following options:
- `--check-contents`
- `--check-contents`\
Checks that the contents of every valid store path has not been
altered by computing a SHA-256 hash of the contents and comparing it
with the hash stored in the Nix database at build time. Paths that
have been modified are printed out. For large stores,
`--check-contents` is obviously quite slow.
Checks that the contents of every valid store path has not been
altered by computing a SHA-256 hash of the contents and comparing it
with the hash stored in the Nix database at build time. Paths that
have been modified are printed out. For large stores,
`--check-contents` is obviously quite slow.
- `--repair`
If any valid path is missing from the store, or (if
`--check-contents` is given) the contents of a valid path has been
modified, then try to repair the path by redownloading it. See
`nix-store --repair-path` for details.
- `--repair`\
If any valid path is missing from the store, or (if
`--check-contents` is given) the contents of a valid path has been
modified, then try to repair the path by redownloading it. See
`nix-store --repair-path` for details.
{{#include ./opt-common.md}}

View File

@@ -37,7 +37,7 @@ Most Nix commands accept the following command-line options:
Print even more informational messages.
- `4` “Debug”
Print debug information.
- `5` “Vomit”
@@ -143,7 +143,7 @@ Most Nix commands accept the following command-line options:
This option is accepted by `nix-env`, `nix-instantiate`, `nix-shell` and `nix-build`.
When evaluating Nix expressions, the expression evaluator will automatically try to call functions that it encounters.
It can automatically call functions for which every argument has a [default value](@docroot@/language/syntax.md#functions) (e.g., `{ argName ? defaultValue }: ...`).
It can automatically call functions for which every argument has a [default value](@docroot@/language/constructs.md#functions) (e.g., `{ argName ? defaultValue }: ...`).
With `--arg`, you can also call functions that have arguments without a default value (or override a default value).
That is, if the evaluator encounters a function with an argument named *name*, it will call it with value *value*.
@@ -187,12 +187,11 @@ Most Nix commands accept the following command-line options:
For `nix-shell`, this option is commonly used to give you a shell in which you can build the packages returned by the expression.
If you want to get a shell which contain the *built* packages ready for use, give your expression to the `nix-shell --packages ` convenience flag instead.
- <span id="opt-I">[`-I` / `--include`](#opt-I)</span> *path*
- <span id="opt-I">[`-I`](#opt-I)</span> *path*
Add an entry to the list of search paths used to resolve [lookup paths](@docroot@/language/constructs/lookup-path.md).
Add an entry to the [Nix expression search path](@docroot@/command-ref/conf-file.md#conf-nix-path).
This option may be given multiple times.
Paths added through `-I` take precedence over the [`nix-path` configuration setting](@docroot@/command-ref/conf-file.md#conf-nix-path) and the [`NIX_PATH` environment variable](@docroot@/command-ref/env-common.md#env-NIX_PATH).
Paths added through `-I` take precedence over [`NIX_PATH`](@docroot@/command-ref/env-common.md#env-NIX_PATH).
- <span id="opt-option">[`--option`](#opt-option)</span> *name* *value*

View File

@@ -389,6 +389,88 @@ colors, no emojis and using ASCII instead of Unicode symbols). The same should
happen when TTY is not detected on STDERR. We should not display progress /
status section, but only print warnings and errors.
## Returning future proof JSON
The schema of JSON output should allow for backwards compatible extension. This section explains how to achieve this.
Two definitions are helpful here, because while JSON only defines one "key-value"
object type, we use it to cover two use cases:
- **dictionary**: a map from names to value that all have the same type. In
C++ this would be a `std::map` with string keys.
- **record**: a fixed set of attributes each with their own type. In C++, this
would be represented by a `struct`.
It is best not to mix these use cases, as that may lead to incompatibilities when the schema changes. For example, adding a record field to a dictionary breaks consumers that assume all JSON object fields to have the same meaning and type.
This leads to the following guidelines:
- The top-level (root) value must be a record.
Otherwise, one can not change the structure of a command's output.
- The value of a dictionary item must be a record.
Otherwise, the item type can not be extended.
- List items should be records.
Otherwise, one can not change the structure of the list items.
If the order of the items does not matter, and each item has a unique key that is a string, consider representing the list as a dictionary instead. If the order of the items needs to be preserved, return a list of records.
- Streaming JSON should return records.
An example of a streaming JSON format is [JSON lines](https://jsonlines.org/), where each line represents a JSON value. These JSON values can be considered top-level values or list items, and they must be records.
### Examples
This is bad, because all keys must be assumed to be store types:
```json
{
"local": { ... },
"remote": { ... },
"http": { ... }
}
```
This is good, because the it is extensible at the root, and is somewhat self-documenting:
```json
{
"storeTypes": { "local": { ... }, ... },
"pluginSupport": true
}
```
While the dictionary of store types seems like a very complete response at first, a use case may arise that warrants returning additional information.
For example, the presence of plugin support may be crucial information for a client to proceed when their desired store type is missing.
The following representation is bad because it is not extensible:
```json
{ "outputs": [ "out" "bin" ] }
```
However, simply converting everything to records is not enough, because the order of outputs must be preserved:
```json
{ "outputs": { "bin": {}, "out": {} } }
```
The first item is the default output. Deriving this information from the outputs ordering is not great, but this is how Nix currently happens to work.
While it is possible for a JSON parser to preserve the order of fields, we can not rely on this capability to be present in all JSON libraries.
This representation is extensible and preserves the ordering:
```json
{ "outputs": [ { "outputName": "out" }, { "outputName": "bin" } ] }
```
## Dialog with the user
CLIs don't always make it clear when an action has taken place. For every

View File

@@ -24,7 +24,7 @@ nix build .#^doc
and open `./result-doc/share/doc/nix/manual/index.html`.
To build the manual incrementally, [enter the development shell](./building.md) and run:
To build the manual incrementally, [enter the development shell](./hacking.md) and run:
```console
make manual-html-open -j $NIX_BUILD_CORES
@@ -196,16 +196,15 @@ You can also build and view it yourself:
[Doxygen API documentation]: https://hydra.nixos.org/job/nix/master/internal-api-docs/latest/download-by-type/doc/internal-api-docs
```console
$ nix build .#hydraJobs.internal-api-docs
$ xdg-open ./result/share/doc/nix/internal-api/html/index.html
# nix build .#hydraJobs.internal-api-docs
# xdg-open ./result/share/doc/nix/internal-api/html/index.html
```
or inside `nix-shell` or `nix develop`:
```console
$ mesonConfigurePhase
$ ninja src/internal-api-docs/html
$ xdg-open src/internal-api-docs/html/index.html
```
# make internal-api-html
# xdg-open ./outputs/doc/share/doc/nix/internal-api/html/index.html
```
## C API documentation
@@ -217,14 +216,13 @@ You can also build and view it yourself:
[C API documentation]: https://hydra.nixos.org/job/nix/master/external-api-docs/latest/download-by-type/doc/external-api-docs
```console
$ nix build .#hydraJobs.external-api-docs
$ xdg-open ./result/share/doc/nix/external-api/html/index.html
# nix build .#hydraJobs.external-api-docs
# xdg-open ./result/share/doc/nix/external-api/html/index.html
```
or inside `nix-shell` or `nix develop`:
```
$ mesonConfigurePhase
$ ninja src/external-api-docs/html
$ xdg-open src/external-api-docs/html/index.html
# make external-api-html
# xdg-open ./outputs/doc/share/doc/nix/external-api/html/index.html
```

View File

@@ -1,67 +1,24 @@
# Building Nix
# Hacking
This section provides some notes on how to start hacking on Nix.
To get the latest version of Nix from GitHub:
This section provides some notes on how to hack on Nix. To get the
latest version of Nix from GitHub:
```console
$ git clone https://github.com/NixOS/nix.git
$ cd nix
```
> **Note**
>
> The following instructions assume you already have some version of Nix installed locally, so that you can use it to set up the development environment.
> If you don't have it installed, follow the [installation instructions](../installation/index.md).
The following instructions assume you already have some version of Nix installed locally, so that you can use it to set up the development environment. If you don't have it installed, follow the [installation instructions].
To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
```console
$ nix-shell
```
To get a shell with one of the other [supported compilation environments](#compilation-environments):
```console
$ nix-shell --attr devShells.x86_64-linux.native-clangStdenvPackages
```
> **Note**
>
> You can use `native-ccacheStdenvPackages` to drastically improve rebuild time.
> By default, [ccache](https://ccache.dev) keeps artifacts in `~/.cache/ccache/`.
To build Nix itself in this shell:
```console
[nix-shell]$ autoreconfPhase
[nix-shell]$ ./configure $configureFlags --prefix=$(pwd)/outputs/out
[nix-shell]$ make -j $NIX_BUILD_CORES
```
To install it in `$(pwd)/outputs` and test it:
```console
[nix-shell]$ make install
[nix-shell]$ make installcheck -j $NIX_BUILD_CORES
[nix-shell]$ ./outputs/out/bin/nix --version
nix (Nix) 2.12
```
To build a release version of Nix for the current operating system and CPU architecture:
```console
$ nix-build
```
You can also build Nix for one of the [supported platforms](#platforms).
[installation instructions]: ../installation/index.md
## Building Nix with flakes
This section assumes you are using Nix with the [`flakes`] and [`nix-command`] experimental features enabled.
See the [Building Nix](#building-nix) section for equivalent instructions using stable Nix interfaces.
[`flakes`]: @docroot@/development/experimental-features.md#xp-feature-flakes
[`nix-command`]: @docroot@/development/experimental-features.md#xp-nix-command
[`flakes`]: @docroot@/contributing/experimental-features.md#xp-feature-flakes
[`nix-command`]: @docroot@/contributing/experimental-features.md#xp-nix-command
To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
@@ -110,6 +67,50 @@ $ nix build
You can also build Nix for one of the [supported platforms](#platforms).
## Building Nix
To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
```console
$ nix-shell
```
To get a shell with one of the other [supported compilation environments](#compilation-environments):
```console
$ nix-shell --attr devShells.x86_64-linux.native-clangStdenvPackages
```
> **Note**
>
> You can use `native-ccacheStdenvPackages` to drastically improve rebuild time.
> By default, [ccache](https://ccache.dev) keeps artifacts in `~/.cache/ccache/`.
To build Nix itself in this shell:
```console
[nix-shell]$ autoreconfPhase
[nix-shell]$ ./configure $configureFlags --prefix=$(pwd)/outputs/out
[nix-shell]$ make -j $NIX_BUILD_CORES
```
To install it in `$(pwd)/outputs` and test it:
```console
[nix-shell]$ make install
[nix-shell]$ make installcheck -j $NIX_BUILD_CORES
[nix-shell]$ ./outputs/out/bin/nix --version
nix (Nix) 2.12
```
To build a release version of Nix for the current operating system and CPU architecture:
```console
$ nix-build
```
You can also build Nix for one of the [supported platforms](#platforms).
## Makefile variables
You may need `profiledir=$out/etc/profile.d` and `sysconfdir=$out/etc` to run `make install`.
@@ -121,6 +122,7 @@ Run `make` with [`-e` / `--environment-overrides`](https://www.gnu.org/software/
The docs can take a while to build, so you may want to disable this for local development.
- `ENABLE_FUNCTIONAL_TESTS=yes` to enable building the functional tests.
- `ENABLE_UNIT_TESTS=yes` to enable building the unit tests.
- `OPTIMIZE=1` to enable optimizations.
- `libraries=libutil programs=` to only build a specific library.
@@ -293,3 +295,81 @@ If it fails, run `git add --patch` to approve the suggestions _and commit again_
To refresh pre-commit hook's config file, do the following:
1. Exit the development shell and start it again by running `nix develop`.
2. If you also use the pre-commit hook, also run `pre-commit-hooks-install` again.
## Add a release note
`doc/manual/rl-next` contains release notes entries for all unreleased changes.
User-visible changes should come with a release note.
### Add an entry
Here's what a complete entry looks like. The file name is not incorporated in the document.
```
---
synopsis: Basically a title
issues: 1234
prs: 1238
---
Here's one or more paragraphs that describe the change.
- It's markdown
- Add references to the manual using @docroot@
```
Significant changes should add the following header, which moves them to the top.
```
significance: significant
```
<!-- Keep an eye on https://codeberg.org/fgaz/changelog-d/issues/1 -->
See also the [format documentation](https://github.com/haskell/cabal/blob/master/CONTRIBUTING.md#changelog).
### Build process
Releases have a precomputed `rl-MAJOR.MINOR.md`, and no `rl-next.md`.
## Branches
- [`master`](https://github.com/NixOS/nix/commits/master)
The main development branch. All changes are approved and merged here.
When developing a change, create a branch based on the latest `master`.
Maintainers try to [keep it in a release-worthy state](#reverting).
- [`maintenance-*.*`](https://github.com/NixOS/nix/branches/all?query=maintenance)
These branches are the subject of backports only, and are
also [kept](#reverting) in a release-worthy state.
See [`maintainers/backporting.md`](https://github.com/NixOS/nix/blob/master/maintainers/backporting.md)
- [`latest-release`](https://github.com/NixOS/nix/tree/latest-release)
The latest patch release of the latest minor version.
See [`maintainers/release-process.md`](https://github.com/NixOS/nix/blob/master/maintainers/release-process.md)
- [`backport-*-to-*`](https://github.com/NixOS/nix/branches/all?query=backport)
Generally branches created by the backport action.
See [`maintainers/backporting.md`](https://github.com/NixOS/nix/blob/master/maintainers/backporting.md)
- [_other_](https://github.com/NixOS/nix/branches/all)
Branches that do not conform to the above patterns should be feature branches.
## Reverting
If a change turns out to be merged by mistake, or contain a regression, it may be reverted.
A revert is not a rejection of the contribution, but merely part of an effective development process.
It makes sure that development keeps running smoothly, with minimal uncertainty, and less overhead.
If maintainers have to worry too much about avoiding reverts, they would not be able to merge as much.
By embracing reverts as a good part of the development process, everyone wins.
However, taking a step back may be frustrating, so maintainers will be extra supportive on the next try.

View File

@@ -5,4 +5,4 @@ Check the [contributing guide](https://github.com/NixOS/nix/blob/master/CONTRIBU
This chapter is a collection of guides for making changes to the code and documentation.
If you're not sure where to start, try to [compile Nix from source](./building.md) and consider [making improvements to documentation](./documentation.md).
If you're not sure where to start, try to [compile Nix from source](./hacking.md) and consider [making improvements to documentation](./documentation.md).

View File

@@ -59,15 +59,15 @@ The unit tests are defined using the [googletest] and [rapidcheck] frameworks.
> …
> ```
The tests for each Nix library (`libnixexpr`, `libnixstore`, etc..) live inside a directory `src/${library_name_without-nix}-test`.
Given an interface (header) and implementation pair in the original library, say, `src/libexpr/value/context.{hh,cc}`, we write tests for it in `src/nix-expr-tests/value/context.cc`, and (possibly) declare/define additional interfaces for testing purposes in `src/nix-expr-test-support/tests/value/context.{hh,cc}`.
The tests for each Nix library (`libnixexpr`, `libnixstore`, etc..) live inside a directory `tests/unit/${library_name_without-nix}`.
Given an interface (header) and implementation pair in the original library, say, `src/libexpr/value/context.{hh,cc}`, we write tests for it in `tests/unit/libexpr/tests/value/context.cc`, and (possibly) declare/define additional interfaces for testing purposes in `tests/unit/libexpr-support/tests/value/context.{hh,cc}`.
Data for unit tests is stored in a `data` subdir of the directory for each unit test executable.
For example, `libnixstore` code is in `src/libstore`, and its test data is in `src/nix-store-tests/data`.
The path to the `src/${library_name_without-nix}-test/data` directory is passed to the unit test executable with the environment variable `_NIX_TEST_UNIT_DATA`.
For example, `libnixstore` code is in `src/libstore`, and its test data is in `tests/unit/libstore/data`.
The path to the `tests/unit/data` directory is passed to the unit test executable with the environment variable `_NIX_TEST_UNIT_DATA`.
Note that each executable only gets the data for its tests.
The unit test libraries are in `src/${library_name_without-nix}-test-support`.
The unit test libraries are in `tests/unit/${library_name_without-nix}-lib`.
All headers are in a `tests` subdirectory so they are included with `#include "tests/"`.
The use of all these separate directories for the unit tests might seem inconvenient, as for example the tests are not "right next to" the part of the code they are testing.
@@ -76,25 +76,8 @@ there is no risk of any build-system wildcards for the library accidentally pick
### Running tests
You can run the whole testsuite with `meson test` from the Meson build directory, or the tests for a specific component with `meson test nix-store-tests`.
A environment variables that Google Test accepts are also worth knowing:
1. [`GTEST_FILTER`](https://google.github.io/googletest/advanced.html#running-a-subset-of-the-tests)
This is used for finer-grained filtering of which tests to run.
2. [`GTEST_BRIEF`](https://google.github.io/googletest/advanced.html#suppressing-test-passes)
This is used to avoid logging passing tests.
Putting the two together, one might run
```bash
GTEST_BRIEF=1 GTEST_FILTER='ErrorTraceTest.*' meson test nix-expr-tests -v
```
for short but comprensive output.
You can run the whole testsuite with `make check`, or the tests for a specific component with `make libfoo-tests_RUN`.
Finer-grained filtering is also possible using the [--gtest_filter](https://google.github.io/googletest/advanced.html#running-a-subset-of-the-tests) command-line option, or the `GTEST_FILTER` environment variable, e.g. `GTEST_FILTER='ErrorTraceTest.*' make check`.
### Characterisation testing { #characaterisation-testing-unit }
@@ -103,7 +86,7 @@ See [functional characterisation testing](#characterisation-testing-functional)
Like with the functional characterisation, `_NIX_TEST_ACCEPT=1` is also used.
For example:
```shell-session
$ _NIX_TEST_ACCEPT=1 meson test nix-store-tests -v
$ _NIX_TEST_ACCEPT=1 make libstore-tests_RUN
...
[ SKIPPED ] WorkerProtoTest.string_read
[ SKIPPED ] WorkerProtoTest.string_write
@@ -131,8 +114,6 @@ On other platforms they wouldn't be run at all.
The functional tests reside under the `tests/functional` directory and are listed in `tests/functional/local.mk`.
Each test is a bash script.
Functional tests are run during `installCheck` in the `nix` package build, as well as separately from the build, in VM tests.
### Running the whole test suite
The whole test suite can be run with:
@@ -271,30 +252,13 @@ Regressions are caught, and improvements always show up in code review.
To ensure that characterisation testing doesn't make it harder to intentionally change these interfaces, there always must be an easy way to regenerate the expected output, as we do with `_NIX_TEST_ACCEPT=1`.
### Running functional tests on NixOS
We run the functional tests not just in the build, but also in VM tests.
This helps us ensure that Nix works correctly on NixOS, and environments that have similar characteristics that are hard to reproduce in a build environment.
The recommended way to run these tests during development is:
```shell
nix build .#hydraJobs.tests.functional_user.quickBuild
```
The `quickBuild` attribute configures the test to use a `nix` package that's built without integration tests, so that you can iterate on the tests without performing recompilations due to the changed sources for `installCheck`.
Generally, this build is sufficient, but in nightly or CI we also test the attributes `functional_root` and `functional_trusted`, in which the test suite is run with different levels of authorization.
## Integration tests
The integration tests are defined in the Nix flake under the `hydraJobs.tests` attribute.
These tests include everything that needs to interact with external services or run Nix in a non-trivial distributed setup.
Because these tests are expensive and require more than what the standard github-actions setup provides, they only run on the master branch (on <https://hydra.nixos.org/jobset/nix/master>).
You can run them manually with `nix build .#hydraJobs.tests.{testName}` or `nix-build -A hydraJobs.tests.{testName}`.
If you are testing a build of `nix` that you haven't compiled yet, you may iterate faster by appending the `quickBuild` attribute: `nix build .#hydraJobs.tests.{testName}.quickBuild`.
You can run them manually with `nix build .#hydraJobs.tests.{testName}` or `nix-build -A hydraJobs.tests.{testName}`
## Installer tests

View File

@@ -1,79 +0,0 @@
# Contributing
## Add a release note
`doc/manual/rl-next` contains release notes entries for all unreleased changes.
User-visible changes should come with a release note.
### Add an entry
Here's what a complete entry looks like. The file name is not incorporated in the document.
```
---
synopsis: Basically a title
issues: 1234
prs: 1238
---
Here's one or more paragraphs that describe the change.
- It's markdown
- Add references to the manual using @docroot@
```
Significant changes should add the following header, which moves them to the top.
```
significance: significant
```
<!-- Keep an eye on https://codeberg.org/fgaz/changelog-d/issues/1 -->
See also the [format documentation](https://github.com/haskell/cabal/blob/master/CONTRIBUTING.md#changelog).
### Build process
Releases have a precomputed `rl-MAJOR.MINOR.md`, and no `rl-next.md`.
## Branches
- [`master`](https://github.com/NixOS/nix/commits/master)
The main development branch. All changes are approved and merged here.
When developing a change, create a branch based on the latest `master`.
Maintainers try to [keep it in a release-worthy state](#reverting).
- [`maintenance-*.*`](https://github.com/NixOS/nix/branches/all?query=maintenance)
These branches are the subject of backports only, and are
also [kept](#reverting) in a release-worthy state.
See [`maintainers/backporting.md`](https://github.com/NixOS/nix/blob/master/maintainers/backporting.md)
- [`latest-release`](https://github.com/NixOS/nix/tree/latest-release)
The latest patch release of the latest minor version.
See [`maintainers/release-process.md`](https://github.com/NixOS/nix/blob/master/maintainers/release-process.md)
- [`backport-*-to-*`](https://github.com/NixOS/nix/branches/all?query=backport)
Generally branches created by the backport action.
See [`maintainers/backporting.md`](https://github.com/NixOS/nix/blob/master/maintainers/backporting.md)
- [_other_](https://github.com/NixOS/nix/branches/all)
Branches that do not conform to the above patterns should be feature branches.
## Reverting
If a change turns out to be merged by mistake, or contain a regression, it may be reverted.
A revert is not a rejection of the contribution, but merely part of an effective development process.
It makes sure that development keeps running smoothly, with minimal uncertainty, and less overhead.
If maintainers have to worry too much about avoiding reverts, they would not be able to merge as much.
By embracing reverts as a good part of the development process, everyone wins.
However, taking a step back may be frustrating, so maintainers will be extra supportive on the next try.

View File

@@ -1,128 +0,0 @@
# JSON guideline
Nix consumes and produces JSON in a variety of contexts.
These guidelines ensure consistent practices for all our JSON interfaces, for ease of use, and so that experience in one part carries over to another.
## Extensibility
The schema of JSON input and output should allow for backwards compatible extension.
This section explains how to achieve this.
Two definitions are helpful here, because while JSON only defines one "key-value" object type, we use it to cover two use cases:
- **dictionary**: a map from names to value that all have the same type.
In C++ this would be a `std::map` with string keys.
- **record**: a fixed set of attributes each with their own type.
In C++, this would be represented by a `struct`.
It is best not to mix these use cases, as that may lead to incompatibilities when the schema changes.
For example, adding a record field to a dictionary breaks consumers that assume all JSON object fields to have the same meaning and type, and dictionary items with a colliding name can not be represented anymore.
This leads to the following guidelines:
- The top-level (root) value must be a record.
Otherwise, one can not change the structure of a command's output.
- The value of a dictionary item must be a record.
Otherwise, the item type can not be extended.
- List items should be records.
Otherwise, one can not change the structure of the list items.
If the order of the items does not matter, and each item has a unique key that is a string, consider representing the list as a dictionary instead.
If the order of the items needs to be preserved, return a list of records.
- Streaming JSON should return records.
An example of a streaming JSON format is [JSON lines](https://jsonlines.org/), where each line represents a JSON value.
These JSON values can be considered top-level values or list items, and they must be records.
### Examples
This is bad, because all keys must be assumed to be store types:
```json
{
"local": { ... },
"remote": { ... },
"http": { ... }
}
```
This is good, because the it is extensible at the root, and is somewhat self-documenting:
```json
{
"storeTypes": { "local": { ... }, ... },
"pluginSupport": true
}
```
While the dictionary of store types seems like a very complete response at first, a use case may arise that warrants returning additional information.
For example, the presence of plugin support may be crucial information for a client to proceed when their desired store type is missing.
The following representation is bad because it is not extensible:
```json
{ "outputs": [ "out" "bin" ] }
```
However, simply converting everything to records is not enough, because the order of outputs must be preserved:
```json
{ "outputs": { "bin": {}, "out": {} } }
```
The first item is the default output. Deriving this information from the outputs ordering is not great, but this is how Nix currently happens to work.
While it is possible for a JSON parser to preserve the order of fields, we can not rely on this capability to be present in all JSON libraries.
This representation is extensible and preserves the ordering:
```json
{ "outputs": [ { "outputName": "out" }, { "outputName": "bin" } ] }
```
## Self-describing values
As described in the previous section, it's crucial that schemas can be extended with with new fields without breaking compatibility.
However, that should *not* mean we use the presence/absence of fields to indicate optional information *within* a version of the schema.
Instead, always include the field, and use `null` to indicate the "nothing" case.
### Examples
Here are two JSON objects:
```json
{
"foo": {}
}
```
```json
{
"foo": {},
"bar": {}
}
```
Since they differ in which fields they contain, they should *not* both be valid values of the same schema.
At most, they can match two different schemas where the second (with `foo` and `bar`) is considered a newer version of the first (with just `foo`).
Within each version, all fields are mandatory (always `foo`, and always `foo` and `bar`).
Only *between* each version, `bar` gets added as a new mandatory field.
Here are another two JSON objects:
```json
{ "foo": null }
```
```json
{ "foo": { "bar": 1 } }
```
Since they both contain a `foo` field, they could be valid values of the same schema.
The schema would have `foo` has an optional field, which is either `null` or an object where `bar` is an integer.

View File

@@ -12,7 +12,7 @@
For how Nix uses content addresses, see:
- [Content-Addressing File System Objects](@docroot@/store/file-system-object/content-address.md)
- [Content-Addressing Store Objects](@docroot@/store/store-object/content-address.md)
- [content-addressed store object](#gloss-content-addressed-store-object)
- [content-addressed derivation](#gloss-content-addressed-derivation)
Software Heritage's writing on [*Intrinsic and Extrinsic identifiers*](https://www.softwareheritage.org/2020/07/09/intrinsic-vs-extrinsic-identifiers) is also a good introduction to the value of content-addressing over other referencing schemes.
@@ -71,9 +71,10 @@
[`__contentAddressed`](./language/advanced-attributes.md#adv-attr-__contentAddressed)
attribute set to `true`.
- [fixed-output derivation]{#gloss-fixed-output-derivation} (FOD)
- [fixed-output derivation]{#gloss-fixed-output-derivation}
A [derivation] where a cryptographic hash of the [output] is determined in advance using the [`outputHash`](./language/advanced-attributes.md#adv-attr-outputHash) attribute, and where the [`builder`](@docroot@/language/derivations.md#attr-builder) executable has access to the network.
A derivation which includes the
[`outputHash`](./language/advanced-attributes.md#adv-attr-outputHash) attribute.
- [store]{#gloss-store}
@@ -136,12 +137,9 @@
- [content-addressed store object]{#gloss-content-addressed-store-object}
A [store object] which is [content-addressed](#gloss-content-address),
i.e. whose [store path] is determined by its contents.
A [store object] whose [store path] is determined by its contents.
This includes derivations, the outputs of [content-addressed derivations](#gloss-content-addressed-derivation), and the outputs of [fixed-output derivations](#gloss-fixed-output-derivation).
See [Content-Addressing Store Objects](@docroot@/store/store-object/content-address.md) for details.
- [substitute]{#gloss-substitute}
A substitute is a command invocation stored in the [Nix database] that
@@ -168,7 +166,7 @@
- [impure derivation]{#gloss-impure-derivation}
[An experimental feature](#@docroot@/development/experimental-features.md#xp-feature-impure-derivations) that allows derivations to be explicitly marked as impure,
[An experimental feature](#@docroot@/contributing/experimental-features.md#xp-feature-impure-derivations) that allows derivations to be explicitly marked as impure,
so that they are always rebuilt, and their outputs not reused by subsequent calls to realise them.
- [Nix database]{#gloss-nix-database}
@@ -312,7 +310,7 @@
- [package attribute set]{#package-attribute-set}
An [attribute set](@docroot@/language/types.md#attribute-set) containing the attribute `type = "derivation";` (derivation for historical reasons), as well as other attributes, such as
An [attribute set](@docroot@/language/values.md#attribute-set) containing the attribute `type = "derivation";` (derivation for historical reasons), as well as other attributes, such as
- attributes that refer to the files of a [package], typically in the form of [derivation outputs](#output),
- attributes that declare something about how the package is supposed to be installed or used,
- other metadata or arbitrary attributes.
@@ -325,9 +323,9 @@
See [String interpolation](./language/string-interpolation.md) for details.
[string]: ./language/types.md#type-string
[path]: ./language/types.md#type-path
[attribute name]: ./language/types.md#attribute-set
[string]: ./language/values.md#type-string
[path]: ./language/values.md#type-path
[attribute name]: ./language/values.md#attribute-set
- [base directory]{#gloss-base-directory}
@@ -353,7 +351,7 @@
Not yet stabilized functionality guarded by named experimental feature flags.
These flags are enabled or disabled with the [`experimental-features`](./command-ref/conf-file.html#conf-experimental-features) setting.
See the contribution guide on the [purpose and lifecycle of experimental feaures](@docroot@/development/experimental-features.md).
See the contribution guide on the [purpose and lifecycle of experimental feaures](@docroot@/contributing/experimental-features.md).
[Nix language]: ./language/index.md

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@@ -77,7 +77,7 @@ $ su root
# Installing from a binary tarball
You can also download a binary tarball that contains Nix and all its dependencies:
- Choose a [version](https://releases.nixos.org/?prefix=nix/) and [system type](../development/building.md#platforms)
- Choose a [version](https://releases.nixos.org/?prefix=nix/) and [system type](../contributing/hacking.md#platforms)
- Download and unpack the tarball
- Run the installer

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@@ -113,18 +113,19 @@ Derivations can declare some infrequently used optional attributes.
> `nix-build`.
If the [`configurable-impure-env` experimental
feature](@docroot@/development/experimental-features.md#xp-feature-configurable-impure-env)
feature](@docroot@/contributing/experimental-features.md#xp-feature-configurable-impure-env)
is enabled, these environment variables can also be controlled
through the
[`impure-env`](@docroot@/command-ref/conf-file.md#conf-impure-env)
configuration setting.
- [`outputHash`]{#adv-attr-outputHash}; [`outputHashAlgo`]{#adv-attr-outputHashAlgo}; [`outputHashMode`]{#adv-attr-outputHashMode}\
These attributes declare that the derivation is a so-called *fixed-output derivation* (FOD), which means that a cryptographic hash of the output is already known in advance.
As opposed to regular derivations, the [`builder`] executable of a fixed-output derivation has access to the network.
Nix computes a cryptographic hash of its output and compares that to the hash declared with these attributes.
If there is a mismatch, the derivation fails.
These attributes declare that the derivation is a so-called
*fixed-output derivation*, which means that a cryptographic hash of
the output is already known in advance. When the build of a
fixed-output derivation finishes, Nix computes the cryptographic
hash of the output and compares it to the hash declared with these
attributes. If there is a mismatch, the build fails.
The rationale for fixed-output derivations is derivations such as
those produced by the `fetchurl` function. This function downloads a
@@ -226,7 +227,7 @@ Derivations can declare some infrequently used optional attributes.
- [`__contentAddressed`]{#adv-attr-__contentAddressed}
> **Warning**
> This attribute is part of an [experimental feature](@docroot@/development/experimental-features.md).
> This attribute is part of an [experimental feature](@docroot@/contributing/experimental-features.md).
>
> To use this attribute, you must enable the
> [`ca-derivations`][xp-feature-ca-derivations] experimental feature.
@@ -278,9 +279,7 @@ Derivations can declare some infrequently used optional attributes.
> **Note**
>
> If set to `false`, the [`builder`] should be able to run on the system type specified in the [`system` attribute](./derivations.md#attr-system), since the derivation cannot be substituted.
[`builder`]: ./derivations.md#attr-builder
> If set to `false`, the [`builder`](./derivations.md#attr-builder) should be able to run on the system type specified in the [`system` attribute](./derivations.md#attr-system), since the derivation cannot be substituted.
- [`__structuredAttrs`]{#adv-attr-structuredAttrs}\
If the special attribute `__structuredAttrs` is set to `true`, the other derivation
@@ -302,12 +301,6 @@ Derivations can declare some infrequently used optional attributes.
(associative) arrays. For example, the attribute `hardening.format = true`
ends up as the Bash associative array element `${hardening[format]}`.
> **Warning**
>
> If set to `true`, other advanced attributes such as [`allowedReferences`](#adv-attr-allowedReferences), [`allowedReferences`](#adv-attr-allowedReferences), [`allowedRequisites`](#adv-attr-allowedRequisites),
[`disallowedReferences`](#adv-attr-disallowedReferences) and [`disallowedRequisites`](#adv-attr-disallowedRequisites), maxSize, and maxClosureSize.
will have no effect.
- [`outputChecks`]{#adv-attr-outputChecks}\
When using [structured attributes](#adv-attr-structuredAttrs), the `outputChecks`
attribute allows defining checks per-output.
@@ -370,6 +363,6 @@ Derivations can declare some infrequently used optional attributes.
ensures that the derivation can only be built on a machine with the `kvm` feature.
[xp-feature-ca-derivations]: @docroot@/development/experimental-features.md#xp-feature-ca-derivations
[xp-feature-dynamic-derivations]: @docroot@/development/experimental-features.md#xp-feature-dynamic-derivations
[xp-feature-git-hashing]: @docroot@/development/experimental-features.md#xp-feature-git-hashing
[xp-feature-ca-derivations]: @docroot@/contributing/experimental-features.md#xp-feature-ca-derivations
[xp-feature-dynamic-derivations]: @docroot@/contributing/experimental-features.md#xp-feature-dynamic-derivations
[xp-feature-git-hashing]: @docroot@/contributing/experimental-features.md#xp-feature-git-hashing

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@@ -0,0 +1,5 @@
# Built-in Constants
These constants are built into the Nix language evaluator:
<dl>

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@@ -0,0 +1 @@
</dl>

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@@ -1,11 +1,9 @@
# Built-ins
# Built-in Functions
This section lists the values and functions built into the Nix language evaluator.
All built-ins are available through the global [`builtins`](#builtins-builtins) constant.
This section lists the functions built into the Nix language evaluator.
All built-in functions are available through the global [`builtins`](./builtin-constants.md#builtins-builtins) constant.
Some built-ins are also exposed directly in the global scope:
<!-- TODO(@rhendric, #10970): this list is incomplete -->
For convenience, some built-ins can be accessed directly:
- [`derivation`](#builtins-derivation)
- [`import`](#builtins-import)

View File

@@ -0,0 +1,486 @@
# Language Constructs
## Recursive sets
Recursive sets are like normal [attribute sets](./values.md#attribute-set), but the attributes can refer to each other.
> *rec-attrset* = `rec {` [ *name* `=` *expr* `;` `]`... `}`
Example:
```nix
rec {
x = y;
y = 123;
}.x
```
This evaluates to `123`.
Note that without `rec` the binding `x = y;` would
refer to the variable `y` in the surrounding scope, if one exists, and
would be invalid if no such variable exists. That is, in a normal
(non-recursive) set, attributes are not added to the lexical scope; in a
recursive set, they are.
Recursive sets of course introduce the danger of infinite recursion. For
example, the expression
```nix
rec {
x = y;
y = x;
}.x
```
will crash with an `infinite recursion encountered` error message.
## Let-expressions
A let-expression allows you to define local variables for an expression.
> *let-in* = `let` [ *identifier* = *expr* ]... `in` *expr*
Example:
```nix
let
x = "foo";
y = "bar";
in x + y
```
This evaluates to `"foobar"`.
## Inheriting attributes
When defining an [attribute set](./values.md#attribute-set) or in a [let-expression](#let-expressions) it is often convenient to copy variables from the surrounding lexical scope (e.g., when you want to propagate attributes).
This can be shortened using the `inherit` keyword.
Example:
```nix
let x = 123; in
{
inherit x;
y = 456;
}
```
is equivalent to
```nix
let x = 123; in
{
x = x;
y = 456;
}
```
and both evaluate to `{ x = 123; y = 456; }`.
> **Note**
>
> This works because `x` is added to the lexical scope by the `let` construct.
It is also possible to inherit attributes from another attribute set.
Example:
In this fragment from `all-packages.nix`,
```nix
graphviz = (import ../tools/graphics/graphviz) {
inherit fetchurl stdenv libpng libjpeg expat x11 yacc;
inherit (xorg) libXaw;
};
xorg = {
libX11 = ...;
libXaw = ...;
...
}
libpng = ...;
libjpg = ...;
...
```
the set used in the function call to the function defined in
`../tools/graphics/graphviz` inherits a number of variables from the
surrounding scope (`fetchurl` ... `yacc`), but also inherits `libXaw`
(the X Athena Widgets) from the `xorg` set.
Summarizing the fragment
```nix
...
inherit x y z;
inherit (src-set) a b c;
...
```
is equivalent to
```nix
...
x = x; y = y; z = z;
a = src-set.a; b = src-set.b; c = src-set.c;
...
```
when used while defining local variables in a let-expression or while
defining a set.
In a `let` expression, `inherit` can be used to selectively bring specific attributes of a set into scope. For example
```nix
let
x = { a = 1; b = 2; };
inherit (builtins) attrNames;
in
{
names = attrNames x;
}
```
is equivalent to
```nix
let
x = { a = 1; b = 2; };
in
{
names = builtins.attrNames x;
}
```
both evaluate to `{ names = [ "a" "b" ]; }`.
## Functions
Functions have the following form:
```nix
pattern: body
```
The pattern specifies what the argument of the function must look like,
and binds variables in the body to (parts of) the argument. There are
three kinds of patterns:
- If a pattern is a single identifier, then the function matches any
argument. Example:
```nix
let negate = x: !x;
concat = x: y: x + y;
in if negate true then concat "foo" "bar" else ""
```
Note that `concat` is a function that takes one argument and returns
a function that takes another argument. This allows partial
parameterisation (i.e., only filling some of the arguments of a
function); e.g.,
```nix
map (concat "foo") [ "bar" "bla" "abc" ]
```
evaluates to `[ "foobar" "foobla" "fooabc" ]`.
- A *set pattern* of the form `{ name1, name2, …, nameN }` matches a
set containing the listed attributes, and binds the values of those
attributes to variables in the function body. For example, the
function
```nix
{ x, y, z }: z + y + x
```
can only be called with a set containing exactly the attributes `x`,
`y` and `z`. No other attributes are allowed. If you want to allow
additional arguments, you can use an ellipsis (`...`):
```nix
{ x, y, z, ... }: z + y + x
```
This works on any set that contains at least the three named
attributes.
It is possible to provide *default values* for attributes, in
which case they are allowed to be missing. A default value is
specified by writing `name ? e`, where *e* is an arbitrary
expression. For example,
```nix
{ x, y ? "foo", z ? "bar" }: z + y + x
```
specifies a function that only requires an attribute named `x`, but
optionally accepts `y` and `z`.
- An `@`-pattern provides a means of referring to the whole value
being matched:
```nix
args@{ x, y, z, ... }: z + y + x + args.a
```
but can also be written as:
```nix
{ x, y, z, ... } @ args: z + y + x + args.a
```
Here `args` is bound to the argument *as passed*, which is further
matched against the pattern `{ x, y, z, ... }`.
The `@`-pattern makes mainly sense with an ellipsis(`...`) as
you can access attribute names as `a`, using `args.a`, which was
given as an additional attribute to the function.
> **Warning**
>
> `args@` binds the name `args` to the attribute set that is passed to the function.
> In particular, `args` does *not* include any default values specified with `?` in the function's set pattern.
>
> For instance
>
> ```nix
> let
> f = args@{ a ? 23, ... }: [ a args ];
> in
> f {}
> ```
>
> is equivalent to
>
> ```nix
> let
> f = args @ { ... }: [ (args.a or 23) args ];
> in
> f {}
> ```
>
> and both expressions will evaluate to:
>
> ```nix
> [ 23 {} ]
> ```
Note that functions do not have names. If you want to give them a name,
you can bind them to an attribute, e.g.,
```nix
let concat = { x, y }: x + y;
in concat { x = "foo"; y = "bar"; }
```
## Conditionals
Conditionals look like this:
```nix
if e1 then e2 else e3
```
where *e1* is an expression that should evaluate to a Boolean value
(`true` or `false`).
## Assertions
Assertions are generally used to check that certain requirements on or
between features and dependencies hold. They look like this:
```nix
assert e1; e2
```
where *e1* is an expression that should evaluate to a Boolean value. If
it evaluates to `true`, *e2* is returned; otherwise expression
evaluation is aborted and a backtrace is printed.
Here is a Nix expression for the Subversion package that shows how
assertions can be used:.
```nix
{ localServer ? false
, httpServer ? false
, sslSupport ? false
, pythonBindings ? false
, javaSwigBindings ? false
, javahlBindings ? false
, stdenv, fetchurl
, openssl ? null, httpd ? null, db4 ? null, expat, swig ? null, j2sdk ? null
}:
assert localServer -> db4 != null; ①
assert httpServer -> httpd != null && httpd.expat == expat; ②
assert sslSupport -> openssl != null && (httpServer -> httpd.openssl == openssl); ③
assert pythonBindings -> swig != null && swig.pythonSupport;
assert javaSwigBindings -> swig != null && swig.javaSupport;
assert javahlBindings -> j2sdk != null;
stdenv.mkDerivation {
name = "subversion-1.1.1";
...
openssl = if sslSupport then openssl else null; ④
...
}
```
The points of interest are:
1. This assertion states that if Subversion is to have support for
local repositories, then Berkeley DB is needed. So if the Subversion
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
because in this configuration Subversion code ends up being linked
with Apache code, and if the Expat libraries do not match, a build-
or runtime link error or incompatibility might occur.
3. This assertion says that in order for Subversion to have SSL support
(so that it can access `https` URLs), an OpenSSL library must be
passed. Additionally, it says that *if* Apache support is enabled,
then Apache's OpenSSL should match Subversion's. (Note that if
Apache support is not enabled, we don't care about Apache's
OpenSSL.)
4. The conditional here is not really related to assertions, but is
worth pointing out: it ensures that if SSL support is disabled, then
the Subversion derivation is not dependent on OpenSSL, even if a
non-`null` value was passed. This prevents an unnecessary rebuild of
Subversion if OpenSSL changes.
## With-expressions
A *with-expression*,
```nix
with e1; e2
```
introduces the set *e1* into the lexical scope of the expression *e2*.
For instance,
```nix
let as = { x = "foo"; y = "bar"; };
in with as; x + y
```
evaluates to `"foobar"` since the `with` adds the `x` and `y` attributes
of `as` to the lexical scope in the expression `x + y`. The most common
use of `with` is in conjunction with the `import` function. E.g.,
```nix
with (import ./definitions.nix); ...
```
makes all attributes defined in the file `definitions.nix` available as
if they were defined locally in a `let`-expression.
The bindings introduced by `with` do not shadow bindings introduced by
other means, e.g.
```nix
let a = 3; in with { a = 1; }; let a = 4; in with { a = 2; }; ...
```
establishes the same scope as
```nix
let a = 1; in let a = 2; in let a = 3; in let a = 4; in ...
```
Variables coming from outer `with` expressions *are* shadowed:
```nix
with { a = "outer"; };
with { a = "inner"; };
a
```
Does evaluate to `"inner"`.
## Comments
- Inline comments start with `#` and run until the end of the line.
> **Example**
>
> ```nix
> # A number
> 2 # Equals 1 + 1
> ```
>
> ```console
> 2
> ```
- Block comments start with `/*` and run until the next occurrence of `*/`.
> **Example**
>
> ```nix
> /*
> Block comments
> can span multiple lines.
> */ "hello"
> ```
>
> ```console
> "hello"
> ```
This means that block comments cannot be nested.
> **Example**
>
> ```nix
> /* /* nope */ */ 1
> ```
>
> ```console
> error: syntax error, unexpected '*'
>
> at «string»:1:15:
>
> 1| /* /* nope */ *
> | ^
> ```
Consider escaping nested comments and unescaping them in post-processing.
> **Example**
>
> ```nix
> /* /* nested *\/ */ 1
> ```
>
> ```console
> 1
> ```
## Scoping rules
Nix is [statically scoped](https://en.wikipedia.org/wiki/Scope_(computer_science)#Lexical_scope), but with multiple scopes and shadowing rules.
* primary scope --- explicitly-bound variables
* [`let`](#let-expressions)
* [`inherit`](#inheriting-attributes)
* function arguments
* secondary scope --- implicitly-bound variables
* [`with`](#with-expressions)
Primary scope takes precedence over secondary scope.
See [`with`](#with-expressions) for a detailed example.

View File

@@ -4,9 +4,9 @@
>
> *lookup-path* = `<` *identifier* [ `/` *identifier* ]... `>`
A lookup path is an identifier with an optional path suffix that resolves to a [path value](@docroot@/language/types.md#type-path) if the identifier matches a search path entry.
A lookup path is an identifier with an optional path suffix that resolves to a [path value](@docroot@/language/values.md#type-path) if the identifier matches a search path entry.
The value of a lookup path is determined by [`builtins.nixPath`](@docroot@/language/builtins.md#builtins-nixPath).
The value of a lookup path is determined by [`builtins.nixPath`](@docroot@/language/builtin-constants.md#builtins-nixPath).
See [`builtins.findFile`](@docroot@/language/builtins.md#builtins-findFile) for details on lookup path resolution.

View File

@@ -12,7 +12,7 @@ It outputs an attribute set, and produces a [store derivation] as a side effect
### Required
- [`name`]{#attr-name} ([String](@docroot@/language/types.md#type-string))
- [`name`]{#attr-name} ([String](@docroot@/language/values.md#type-string))
A symbolic name for the derivation.
It is added to the [store path] of the corresponding [store derivation] as well as to its [output paths](@docroot@/glossary.md#gloss-output-path).
@@ -31,7 +31,7 @@ It outputs an attribute set, and produces a [store derivation] as a side effect
> The store derivation's path will be `/nix/store/<hash>-hello.drv`.
> The [output](#attr-outputs) paths will be of the form `/nix/store/<hash>-hello[-<output>]`
- [`system`]{#attr-system} ([String](@docroot@/language/types.md#type-string))
- [`system`]{#attr-system} ([String](@docroot@/language/values.md#type-string))
The system type on which the [`builder`](#attr-builder) executable is meant to be run.
@@ -64,9 +64,9 @@ It outputs an attribute set, and produces a [store derivation] as a side effect
> }
> ```
>
> [`builtins.currentSystem`](@docroot@/language/builtins.md#builtins-currentSystem) has the value of the [`system` configuration option], and defaults to the system type of the current Nix installation.
> [`builtins.currentSystem`](@docroot@/language/builtin-constants.md#builtins-currentSystem) has the value of the [`system` configuration option], and defaults to the system type of the current Nix installation.
- [`builder`]{#attr-builder} ([Path](@docroot@/language/types.md#type-path) | [String](@docroot@/language/types.md#type-string))
- [`builder`]{#attr-builder} ([Path](@docroot@/language/values.md#type-path) | [String](@docroot@/language/values.md#type-string))
Path to an executable that will perform the build.
@@ -113,7 +113,7 @@ It outputs an attribute set, and produces a [store derivation] as a side effect
### Optional
- [`args`]{#attr-args} ([List](@docroot@/language/types.md#list) of [String](@docroot@/language/types.md#type-string))
- [`args`]{#attr-args} ([List](@docroot@/language/values.md#list) of [String](@docroot@/language/values.md#type-string))
Default: `[ ]`
@@ -132,7 +132,7 @@ It outputs an attribute set, and produces a [store derivation] as a side effect
> };
> ```
- [`outputs`]{#attr-outputs} ([List](@docroot@/language/types.md#list) of [String](@docroot@/language/types.md#type-string))
- [`outputs`]{#attr-outputs} ([List](@docroot@/language/values.md#list) of [String](@docroot@/language/values.md#type-string))
Default: `[ "out" ]`

View File

@@ -1,50 +0,0 @@
# Identifiers
An *identifier* is an [ASCII](https://en.wikipedia.org/wiki/ASCII) character sequence that:
- Starts with a letter (`a-z`, `A-Z`) or underscore (`_`)
- Can contain any number of:
- Letters (`a-z`, `A-Z`)
- Digits (`0-9`)
- Underscores (`_`)
- Apostrophes (`'`)
- Hyphens (`-`)
- Is not one of the [keywords](#keywords)
> **Syntax**
>
> *identifier* ~ `[A-Za-z_][A-Za-z0-9_'-]*`
# Names
A name can be an [identifier](#identifier) or a [string literal](./syntax.md#string-literal).
> **Syntax**
>
> *name* → *identifier* | *string*
Names are used in [attribute sets](./syntax.md#attrs-literal), [`let` bindings](./syntax.md#let-expressions), and [`inherit`](./syntax.md#inheriting attributes).
# Keywords
These keywords are reserved and cannot be used as [identifiers](#identifiers):
- [`assert`](./syntax.md#assertions)
- [`else`][if]
- [`if`][if]
- [`in`][let]
- [`inherit`](./syntax.md#inheriting-attributes)
- [`let`][let]
- [`or`](./operators.md#attribute-selection) (see note)
- [`rec`](./syntax.md#recursive-sets)
- [`then`][if]
- [`with`](./syntax.md#with-expressions)
[if]: ./syntax.md#conditionals
[let]: ./syntax.md#let-expressions
> **Note**
>
> The Nix language evaluator currently allows `or` to be used as a name in some contexts, for backwards compatibility reasons.
> Users are advised not to rely on this.
>
> There are long-standing issues with how `or` is parsed as a name, which can't be resolved without making a breaking change to the language.

View File

@@ -53,7 +53,7 @@ This is an incomplete overview of language features, by example.
<td>
*Basic values ([primitives](@docroot@/language/types.md#primitives))*
*Basic values ([primitives](@docroot@/language/values.md#primitives))*
</td>
@@ -71,7 +71,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [string](@docroot@/language/types.md#type-string)
A [string](@docroot@/language/values.md#type-string)
</td>
</tr>
@@ -102,7 +102,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [comment](@docroot@/language/syntax.md#comments).
A [comment](@docroot@/language/constructs.md#comments).
</td>
</tr>
@@ -130,7 +130,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Booleans](@docroot@/language/types.md#type-boolean)
[Booleans](@docroot@/language/values.md#type-boolean)
</td>
</tr>
@@ -142,7 +142,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Null](@docroot@/language/types.md#type-null) value
[Null](@docroot@/language/values.md#type-null) value
</td>
</tr>
@@ -154,7 +154,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
An [integer](@docroot@/language/types.md#type-int)
An [integer](@docroot@/language/values.md#type-number)
</td>
</tr>
@@ -166,7 +166,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [floating point number](@docroot@/language/types.md#type-float)
A [floating point number](@docroot@/language/values.md#type-number)
</td>
</tr>
@@ -178,7 +178,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
An absolute [path](@docroot@/language/types.md#type-path)
An absolute [path](@docroot@/language/values.md#type-path)
</td>
</tr>
@@ -190,7 +190,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [path](@docroot@/language/types.md#type-path) relative to the file containing this Nix expression
A [path](@docroot@/language/values.md#type-path) relative to the file containing this Nix expression
</td>
</tr>
@@ -202,7 +202,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A home [path](@docroot@/language/types.md#type-path). Evaluates to the `"<user's home directory>/.config"`.
A home [path](@docroot@/language/values.md#type-path). Evaluates to the `"<user's home directory>/.config"`.
</td>
</tr>
@@ -238,7 +238,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
An [attribute set](@docroot@/language/types.md#attribute-set) with attributes named `x` and `y`
An [attribute set](@docroot@/language/values.md#attribute-set) with attributes named `x` and `y`
</td>
</tr>
@@ -262,7 +262,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [recursive set](@docroot@/language/syntax.md#recursive-sets), equivalent to `{ x = "foo"; y = "foobar"; }`.
A [recursive set](@docroot@/language/constructs.md#recursive-sets), equivalent to `{ x = "foo"; y = "foobar"; }`.
</td>
</tr>
@@ -278,7 +278,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Lists](@docroot@/language/types.md#list) with three elements.
[Lists](@docroot@/language/values.md#list) with three elements.
</td>
</tr>
@@ -362,7 +362,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Attribute selection](@docroot@/language/types.md#attribute-set) (evaluates to `1`)
[Attribute selection](@docroot@/language/values.md#attribute-set) (evaluates to `1`)
</td>
</tr>
@@ -374,7 +374,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Attribute selection](@docroot@/language/types.md#attribute-set) with default (evaluates to `3`)
[Attribute selection](@docroot@/language/values.md#attribute-set) with default (evaluates to `3`)
</td>
</tr>
@@ -410,7 +410,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Conditional expression](@docroot@/language/syntax.md#conditionals).
[Conditional expression](@docroot@/language/constructs.md#conditionals).
</td>
</tr>
@@ -422,7 +422,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
[Assertion](@docroot@/language/syntax.md#assertions) check (evaluates to `"yes!"`).
[Assertion](@docroot@/language/constructs.md#assertions) check (evaluates to `"yes!"`).
</td>
</tr>
@@ -434,7 +434,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
Variable definition. See [`let`-expressions](@docroot@/language/syntax.md#let-expressions).
Variable definition. See [`let`-expressions](@docroot@/language/constructs.md#let-expressions).
</td>
</tr>
@@ -448,7 +448,7 @@ This is an incomplete overview of language features, by example.
Add all attributes from the given set to the scope (evaluates to `1`).
See [`with`-expressions](@docroot@/language/syntax.md#with-expressions) for details and shadowing caveats.
See [`with`-expressions](@docroot@/language/constructs.md#with-expressions) for details and shadowing caveats.
</td>
</tr>
@@ -462,7 +462,7 @@ This is an incomplete overview of language features, by example.
Adds the variables to the current scope (attribute set or `let` binding).
Desugars to `pkgs = pkgs; src = src;`.
See [Inheriting attributes](@docroot@/language/syntax.md#inheriting-attributes).
See [Inheriting attributes](@docroot@/language/constructs.md#inheriting-attributes).
</td>
</tr>
@@ -476,14 +476,14 @@ This is an incomplete overview of language features, by example.
Adds the attributes, from the attribute set in parentheses, to the current scope (attribute set or `let` binding).
Desugars to `lib = pkgs.lib; stdenv = pkgs.stdenv;`.
See [Inheriting attributes](@docroot@/language/syntax.md#inheriting-attributes).
See [Inheriting attributes](@docroot@/language/constructs.md#inheriting-attributes).
</td>
</tr>
<tr>
<td>
*[Functions](@docroot@/language/syntax.md#functions) (lambdas)*
*[Functions](@docroot@/language/constructs.md#functions) (lambdas)*
</td>
<td>
@@ -500,7 +500,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) that expects an integer and returns it increased by 1.
A [function](@docroot@/language/constructs.md#functions) that expects an integer and returns it increased by 1.
</td>
</tr>
@@ -512,7 +512,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
Curried [function](@docroot@/language/syntax.md#functions), equivalent to `x: (y: x + y)`. Can be used like a function that takes two arguments and returns their sum.
Curried [function](@docroot@/language/constructs.md#functions), equivalent to `x: (y: x + y)`. Can be used like a function that takes two arguments and returns their sum.
</td>
</tr>
@@ -524,7 +524,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) call (evaluates to 101)
A [function](@docroot@/language/constructs.md#functions) call (evaluates to 101)
</td>
</tr>
@@ -536,7 +536,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) bound to a variable and subsequently called by name (evaluates to 103)
A [function](@docroot@/language/constructs.md#functions) bound to a variable and subsequently called by name (evaluates to 103)
</td>
</tr>
@@ -548,7 +548,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) that expects a set with required attributes `x` and `y` and concatenates them
A [function](@docroot@/language/constructs.md#functions) that expects a set with required attributes `x` and `y` and concatenates them
</td>
</tr>
@@ -560,7 +560,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) that expects a set with required attribute `x` and optional `y`, using `"bar"` as default value for `y`
A [function](@docroot@/language/constructs.md#functions) that expects a set with required attribute `x` and optional `y`, using `"bar"` as default value for `y`
</td>
</tr>
@@ -572,7 +572,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) that expects a set with required attributes `x` and `y` and ignores any other attributes
A [function](@docroot@/language/constructs.md#functions) that expects a set with required attributes `x` and `y` and ignores any other attributes
</td>
</tr>
@@ -586,7 +586,7 @@ This is an incomplete overview of language features, by example.
</td>
<td>
A [function](@docroot@/language/syntax.md#functions) that expects a set with required attributes `x` and `y`, and binds the whole set to `args`
A [function](@docroot@/language/constructs.md#functions) that expects a set with required attributes `x` and `y`, and binds the whole set to `args`
</td>
</tr>

View File

@@ -26,16 +26,12 @@
| Logical conjunction (`AND`) | *bool* `&&` *bool* | left | 12 |
| Logical disjunction (`OR`) | *bool* <code>\|\|</code> *bool* | left | 13 |
| [Logical implication] | *bool* `->` *bool* | right | 14 |
| [Pipe operator] (experimental) | *expr* `\|>` *func* | left | 15 |
| [Pipe operator] (experimental) | *func* `<\|` *expr* | right | 15 |
[string]: ./types.md#type-string
[path]: ./types.md#type-path
[number]: ./types.md#type-float
[list]: ./types.md#list
[attribute set]: ./types.md#attribute-set
<!-- TODO(@rhendric, #10970): ^ rationalize number -> int/float -->
[string]: ./values.md#type-string
[path]: ./values.md#type-path
[number]: ./values.md#type-number
[list]: ./values.md#list
[attribute set]: ./values.md#attribute-set
## Attribute selection
@@ -46,6 +42,12 @@
Select the attribute denoted by attribute path *attrpath* from [attribute set] *attrset*.
If the attribute doesnt exist, return the *expr* after `or` if provided, otherwise abort evaluation.
An attribute path is a dot-separated list of [attribute names](./values.md#attribute-set).
> **Syntax**
>
> *attrpath* = *name* [ `.` *name* ]...
[Attribute selection]: #attribute-selection
## Has attribute
@@ -59,7 +61,7 @@ The result is a [Boolean] value.
See also: [`builtins.hasAttr`](@docroot@/language/builtins.md#builtins-hasAttr)
[Boolean]: ./types.md#type-boolean
[Boolean]: ./values.md#type-boolean
[Has attribute]: #has-attribute
@@ -139,7 +141,7 @@ The result is a string.
Update [attribute set] *attrset1* with names and values from *attrset2*.
The returned attribute set will have all of the attributes in *attrset1* and *attrset2*.
The returned attribute set will have of all the attributes in *attrset1* and *attrset2*.
If an attribute name is present in both, the attribute value from the latter is taken.
[Update]: #update
@@ -170,7 +172,7 @@ All comparison operators are implemented in terms of `<`, and the following equi
- Numbers are type-compatible, see [arithmetic] operators.
- Floating point numbers only differ up to a limited precision.
[function]: ./syntax.md#functions
[function]: ./constructs.md#functions
[Equality]: #equality
@@ -180,34 +182,3 @@ Equivalent to `!`*b1* `||` *b2*.
[Logical implication]: #logical-implication
## Pipe operators
- *a* `|>` *b* is equivalent to *b* *a*
- *a* `<|` *b* is equivalent to *a* *b*
> **Example**
>
> ```
> nix-repl> 1 |> builtins.add 2 |> builtins.mul 3
> 9
>
> nix-repl> builtins.add 1 <| builtins.mul 2 <| 3
> 7
> ```
> **Warning**
>
> This syntax is part of an
> [experimental feature](@docroot@/development/experimental-features.md)
> and may change in future releases.
>
> To use this syntax, make sure the
> [`pipe-operators` experimental feature](@docroot@/development/experimental-features.md#xp-feature-pipe-operators)
> is enabled.
> For example, include the following in [`nix.conf`](@docroot@/command-ref/conf-file.md):
>
> ```
> extra-experimental-features = pipe-operators
> ```
[Pipe operator]: #pipe-operators

View File

@@ -1,14 +0,0 @@
# Scoping rules
Nix is [statically scoped](https://en.wikipedia.org/wiki/Scope_(computer_science)#Lexical_scope), but with multiple scopes and shadowing rules.
* primary scope: explicitly-bound variables
* [`let`](./syntax.md#let-expressions)
* [`inherit`](./syntax.md#inheriting-attributes)
* [function](./syntax.md#functions) arguments
* secondary scope: implicitly-bound variables
* [`with`](./syntax.md#with-expressions)
Primary scope takes precedence over secondary scope.
See [`with`](./syntax.md#with-expressions) for a detailed example.

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@@ -111,7 +111,7 @@ It creates an [attribute set] representing the string context, which can be insp
[`builtins.hasContext`]: ./builtins.md#builtins-hasContext
[`builtins.getContext`]: ./builtins.md#builtins-getContext
[attribute set]: ./types.md#attribute-set
[attribute set]: ./values.md#attribute-set
## Clearing string contexts

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@@ -4,9 +4,9 @@ String interpolation is a language feature where a [string], [path], or [attribu
Such a construct is called *interpolated string*, and the expression inside is an [interpolated expression](#interpolated-expression).
[string]: ./types.md#type-string
[path]: ./types.md#type-path
[attribute set]: ./types.md#attribute-set
[string]: ./values.md#type-string
[path]: ./values.md#type-path
[attribute set]: ./values.md#attribute-set
## Examples
@@ -43,47 +43,6 @@ configureFlags = "
Note that Nix expressions and strings can be arbitrarily nested;
in this case the outer string contains various interpolated expressions that themselves contain strings (e.g., `"-thread"`), some of which in turn contain interpolated expressions (e.g., `${mesa}`).
To write a literal `${` in an regular string, escape it with a backslash (`\`).
> **Example**
>
> ```nix
> "echo \${PATH}"
> ```
>
> "echo ${PATH}"
To write a literal `${` in an indented string, escape it with two single quotes (`''`).
> **Example**
>
> ```nix
> ''
> echo ''${PATH}
> ''
> ```
>
> "echo ${PATH}\n"
`$${` can be written literally in any string.
> **Example**
>
> In Make, `$` in file names or recipes is represented as `$$`, see [GNU `make`: Basics of Variable Reference](https://www.gnu.org/software/make/manual/html_node/Reference.html#Basics-of-Variable-References).
> This can be expressed directly in the Nix language strings:
>
> ```nix
> ''
> MAKEVAR = Hello
> all:
> @export BASHVAR=world; echo $(MAKEVAR) $${BASHVAR}
> ''
> ```
>
> "MAKEVAR = Hello\nall:\n\t@export BASHVAR=world; echo $(MAKEVAR) $\${BASHVAR}\n"
See the [documentation on strings][string] for details.
### Path
Rather than writing

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@@ -1,866 +0,0 @@
# Language Constructs
This section covers syntax and semantics of the Nix language.
## Basic Literals
### String {#string-literal}
*Strings* can be written in three ways.
The most common way is to enclose the string between double quotes, e.g., `"foo bar"`.
Strings can span multiple lines.
The results of other expressions can be included into a string by enclosing them in `${ }`, a feature known as [string interpolation].
[string interpolation]: ./string-interpolation.md
The following must be escaped to represent them within a string, by prefixing with a backslash (`\`):
- Double quote (`"`)
> **Example**
>
> ```nix
> "\""
> ```
>
> "\""
- Backslash (`\`)
> **Example**
>
> ```nix
> "\\"
> ```
>
> "\\"
- Dollar sign followed by an opening curly bracket (`${`) "dollar-curly"
> **Example**
>
> ```nix
> "\${"
> ```
>
> "\${"
The newline, carriage return, and tab characters can be written as `\n`, `\r` and `\t`, respectively.
A "double-dollar-curly" (`$${`) can be written literally.
> **Example**
>
> ```nix
> "$${"
> ```
>
> "$\${"
String values are output on the terminal with Nix-specific escaping.
Strings written to files will contain the characters encoded by the escaping.
The second way to write string literals is as an *indented string*, which is enclosed between pairs of *double single-quotes* (`''`), like so:
```nix
''
This is the first line.
This is the second line.
This is the third line.
''
```
This kind of string literal intelligently strips indentation from
the start of each line. To be precise, it strips from each line a
number of spaces equal to the minimal indentation of the string as a
whole (disregarding the indentation of empty lines). For instance,
the first and second line are indented two spaces, while the third
line is indented four spaces. Thus, two spaces are stripped from
each line, so the resulting string is
```nix
"This is the first line.\nThis is the second line.\n This is the third line.\n"
```
> **Note**
>
> Whitespace and newline following the opening `''` is ignored if there is no non-whitespace text on the initial line.
> **Warning**
>
> Prefixed tab characters are not stripped.
>
> > **Example**
> >
> > The following indented string is prefixed with tabs:
> >
> > ''
> > all:
> > @echo hello
> > ''
> >
> > "\tall:\n\t\t@echo hello\n"
Indented strings support [string interpolation].
The following must be escaped to represent them in an indented string:
- `$` is escaped by prefixing it with two single quotes (`''`)
> **Example**
>
> ```nix
> ''
> ''$
> ''
> ```
>
> "$\n"
- `''` is escaped by prefixing it with one single quote (`'`)
> **Example**
>
> ```nix
> ''
> '''
> ''
> ```
>
> "''\n"
These special characters are escaped as follows:
- Linefeed (`\n`): `''\n`
- Carriage return (`\r`): `''\r`
- Tab (`\t`): `''\t`
`''\` escapes any other character.
A "double-dollar-curly" (`$${`) can be written literally.
> **Example**
>
> ```nix
> ''
> $${
> ''
> ```
>
> "$\${\n"
Indented strings are primarily useful in that they allow multi-line
string literals to follow the indentation of the enclosing Nix
expression, and that less escaping is typically necessary for
strings representing languages such as shell scripts and
configuration files because `''` is much less common than `"`.
Example:
```nix
stdenv.mkDerivation {
...
postInstall =
''
mkdir $out/bin $out/etc
cp foo $out/bin
echo "Hello World" > $out/etc/foo.conf
${if enableBar then "cp bar $out/bin" else ""}
'';
...
}
```
Finally, as a convenience, *URIs* as defined in appendix B of
[RFC 2396](http://www.ietf.org/rfc/rfc2396.txt) can be written *as
is*, without quotes. For instance, the string
`"http://example.org/foo.tar.bz2"` can also be written as
`http://example.org/foo.tar.bz2`.
### Number {#number-literal}
<!-- TODO(@rhendric, #10970): split this into int and float -->
Numbers, which can be *integers* (like `123`) or *floating point*
(like `123.43` or `.27e13`).
See [arithmetic] and [comparison] operators for semantics.
[arithmetic]: ./operators.md#arithmetic
[comparison]: ./operators.md#comparison
### Path {#path-literal}
*Paths* can be expressed by path literals such as `./builder.sh`.
A path literal must contain at least one slash to be recognised as such.
For instance, `builder.sh` is not a path:
it's parsed as an expression that selects the attribute `sh` from the variable `builder`.
Path literals are resolved relative to their [base directory](@docroot@/glossary.md#gloss-base-directory).
Path literals may also refer to absolute paths by starting with a slash.
> **Note**
>
> Absolute paths make expressions less portable.
> In the case where a function translates a path literal into an absolute path string for a configuration file, it is recommended to write a string literal instead.
> This avoids some confusion about whether files at that location will be used during evaluation.
> It also avoids unintentional situations where some function might try to copy everything at the location into the store.
If the first component of a path is a `~`, it is interpreted such that the rest of the path were relative to the user's home directory.
For example, `~/foo` would be equivalent to `/home/edolstra/foo` for a user whose home directory is `/home/edolstra`.
Path literals that start with `~` are not allowed in [pure](@docroot@/command-ref/conf-file.md#conf-pure-eval) evaluation.
Path literals can also include [string interpolation], besides being [interpolated into other expressions].
[interpolated into other expressions]: ./string-interpolation.md#interpolated-expressions
At least one slash (`/`) must appear *before* any interpolated expression for the result to be recognized as a path.
`a.${foo}/b.${bar}` is a syntactically valid number division operation.
`./a.${foo}/b.${bar}` is a path.
[Lookup path](./constructs/lookup-path.md) literals such as `<nixpkgs>` also resolve to path values.
## List {#list-literal}
Lists are formed by enclosing a whitespace-separated list of values
between square brackets. For example,
```nix
[ 123 ./foo.nix "abc" (f { x = y; }) ]
```
defines a list of four elements, the last being the result of a call to
the function `f`. Note that function calls have to be enclosed in
parentheses. If they had been omitted, e.g.,
```nix
[ 123 ./foo.nix "abc" f { x = y; } ]
```
the result would be a list of five elements, the fourth one being a
function and the fifth being a set.
Note that lists are only lazy in values, and they are strict in length.
Elements in a list can be accessed using [`builtins.elemAt`](./builtins.md#builtins-elemAt).
## Attribute Set {#attrs-literal}
An attribute set is a collection of name-value-pairs called *attributes*.
Attribute sets are written enclosed in curly brackets (`{ }`).
Attribute names and attribute values are separated by an equal sign (`=`).
Each value can be an arbitrary expression, terminated by a semicolon (`;`)
An attribute name is a string without context, and is denoted by a [name] (an [identifier](./identifiers.md#identifiers) or [string literal](#string-literal)).
[name]: ./identifiers.md#names
> **Syntax**
>
> *attrset* → `{` { *name* `=` *expr* `;` } `}`
Attributes can appear in any order.
An attribute name may only occur once in each attribute set.
> **Example**
>
> This defines an attribute set with attributes named:
> - `x` with the value `123`, an integer
> - `text` with the value `"Hello"`, a string
> - `y` where the value is the result of applying the function `f` to the attribute set `{ bla = 456; }`
>
> ```nix
> {
> x = 123;
> text = "Hello";
> y = f { bla = 456; };
> }
> ```
Attributes in nested attribute sets can be written using *attribute paths*.
> **Syntax**
>
> *attrset* → `{` { *attrpath* `=` *expr* `;` } `}`
An attribute path is a dot-separated list of [names][name].
> **Syntax**
>
> *attrpath* = *name* { `.` *name* }
<!-- -->
> **Example**
>
> ```nix
> { a.b.c = 1; a.b.d = 2; }
> ```
>
> {
> a = {
> b = {
> c = 1;
> d = 2;
> };
> };
> }
Attribute names can also be set implicitly by using the [`inherit` keyword](#inheriting-attributes).
> **Example**
>
> ```nix
> { inherit (builtins) true; }
> ```
>
> { true = true; }
Attributes can be accessed with the [`.` operator](./operators.md#attribute-selection).
Example:
```nix
{ a = "Foo"; b = "Bar"; }.a
```
This evaluates to `"Foo"`.
It is possible to provide a default value in an attribute selection using the `or` keyword.
Example:
```nix
{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"
```
```nix
{ a = "Foo"; b = "Bar"; }.c.d.e.f.g or "Xyzzy"
```
will both evaluate to `"Xyzzy"` because there is no `c` attribute in the set.
You can use arbitrary double-quoted strings as attribute names:
```nix
{ "$!@#?" = 123; }."$!@#?"
```
```nix
let bar = "bar"; in
{ "foo ${bar}" = 123; }."foo ${bar}"
```
Both will evaluate to `123`.
Attribute names support [string interpolation]:
```nix
let bar = "foo"; in
{ foo = 123; }.${bar}
```
```nix
let bar = "foo"; in
{ ${bar} = 123; }.foo
```
Both will evaluate to `123`.
In the special case where an attribute name inside of a set declaration
evaluates to `null` (which is normally an error, as `null` cannot be coerced to
a string), that attribute is simply not added to the set:
```nix
{ ${if foo then "bar" else null} = true; }
```
This will evaluate to `{}` if `foo` evaluates to `false`.
A set that has a `__functor` attribute whose value is callable (i.e. is
itself a function or a set with a `__functor` attribute whose value is
callable) can be applied as if it were a function, with the set itself
passed in first , e.g.,
```nix
let add = { __functor = self: x: x + self.x; };
inc = add // { x = 1; };
in inc 1
```
evaluates to `2`. This can be used to attach metadata to a function
without the caller needing to treat it specially, or to implement a form
of object-oriented programming, for example.
## Recursive sets
Recursive sets are like normal [attribute sets](./types.md#attribute-set), but the attributes can refer to each other.
> *rec-attrset* = `rec {` [ *name* `=` *expr* `;` `]`... `}`
Example:
```nix
rec {
x = y;
y = 123;
}.x
```
This evaluates to `123`.
Note that without `rec` the binding `x = y;` would
refer to the variable `y` in the surrounding scope, if one exists, and
would be invalid if no such variable exists. That is, in a normal
(non-recursive) set, attributes are not added to the lexical scope; in a
recursive set, they are.
Recursive sets of course introduce the danger of infinite recursion. For
example, the expression
```nix
rec {
x = y;
y = x;
}.x
```
will crash with an `infinite recursion encountered` error message.
## Let-expressions
A let-expression allows you to define local variables for an expression.
> *let-in* = `let` [ *identifier* = *expr* ]... `in` *expr*
Example:
```nix
let
x = "foo";
y = "bar";
in x + y
```
This evaluates to `"foobar"`.
## Inheriting attributes
When defining an [attribute set](./types.md#attribute-set) or in a [let-expression](#let-expressions) it is often convenient to copy variables from the surrounding lexical scope (e.g., when you want to propagate attributes).
This can be shortened using the `inherit` keyword.
Example:
```nix
let x = 123; in
{
inherit x;
y = 456;
}
```
is equivalent to
```nix
let x = 123; in
{
x = x;
y = 456;
}
```
and both evaluate to `{ x = 123; y = 456; }`.
> **Note**
>
> This works because `x` is added to the lexical scope by the `let` construct.
It is also possible to inherit attributes from another attribute set.
Example:
In this fragment from `all-packages.nix`,
```nix
graphviz = (import ../tools/graphics/graphviz) {
inherit fetchurl stdenv libpng libjpeg expat x11 yacc;
inherit (xorg) libXaw;
};
xorg = {
libX11 = ...;
libXaw = ...;
...
}
libpng = ...;
libjpg = ...;
...
```
the set used in the function call to the function defined in
`../tools/graphics/graphviz` inherits a number of variables from the
surrounding scope (`fetchurl` ... `yacc`), but also inherits `libXaw`
(the X Athena Widgets) from the `xorg` set.
Summarizing the fragment
```nix
...
inherit x y z;
inherit (src-set) a b c;
...
```
is equivalent to
```nix
...
x = x; y = y; z = z;
a = src-set.a; b = src-set.b; c = src-set.c;
...
```
when used while defining local variables in a let-expression or while
defining a set.
In a `let` expression, `inherit` can be used to selectively bring specific attributes of a set into scope. For example
```nix
let
x = { a = 1; b = 2; };
inherit (builtins) attrNames;
in
{
names = attrNames x;
}
```
is equivalent to
```nix
let
x = { a = 1; b = 2; };
in
{
names = builtins.attrNames x;
}
```
both evaluate to `{ names = [ "a" "b" ]; }`.
## Functions
Functions have the following form:
```nix
pattern: body
```
The pattern specifies what the argument of the function must look like,
and binds variables in the body to (parts of) the argument. There are
three kinds of patterns:
- If a pattern is a single identifier, then the function matches any
argument. Example:
```nix
let negate = x: !x;
concat = x: y: x + y;
in if negate true then concat "foo" "bar" else ""
```
Note that `concat` is a function that takes one argument and returns
a function that takes another argument. This allows partial
parameterisation (i.e., only filling some of the arguments of a
function); e.g.,
```nix
map (concat "foo") [ "bar" "bla" "abc" ]
```
evaluates to `[ "foobar" "foobla" "fooabc" ]`.
- A *set pattern* of the form `{ name1, name2, …, nameN }` matches a
set containing the listed attributes, and binds the values of those
attributes to variables in the function body. For example, the
function
```nix
{ x, y, z }: z + y + x
```
can only be called with a set containing exactly the attributes `x`,
`y` and `z`. No other attributes are allowed. If you want to allow
additional arguments, you can use an ellipsis (`...`):
```nix
{ x, y, z, ... }: z + y + x
```
This works on any set that contains at least the three named
attributes.
It is possible to provide *default values* for attributes, in
which case they are allowed to be missing. A default value is
specified by writing `name ? e`, where *e* is an arbitrary
expression. For example,
```nix
{ x, y ? "foo", z ? "bar" }: z + y + x
```
specifies a function that only requires an attribute named `x`, but
optionally accepts `y` and `z`.
- An `@`-pattern provides a means of referring to the whole value
being matched:
```nix
args@{ x, y, z, ... }: z + y + x + args.a
```
but can also be written as:
```nix
{ x, y, z, ... } @ args: z + y + x + args.a
```
Here `args` is bound to the argument *as passed*, which is further
matched against the pattern `{ x, y, z, ... }`.
The `@`-pattern makes mainly sense with an ellipsis(`...`) as
you can access attribute names as `a`, using `args.a`, which was
given as an additional attribute to the function.
> **Warning**
>
> `args@` binds the name `args` to the attribute set that is passed to the function.
> In particular, `args` does *not* include any default values specified with `?` in the function's set pattern.
>
> For instance
>
> ```nix
> let
> f = args@{ a ? 23, ... }: [ a args ];
> in
> f {}
> ```
>
> is equivalent to
>
> ```nix
> let
> f = args @ { ... }: [ (args.a or 23) args ];
> in
> f {}
> ```
>
> and both expressions will evaluate to:
>
> ```nix
> [ 23 {} ]
> ```
Note that functions do not have names. If you want to give them a name,
you can bind them to an attribute, e.g.,
```nix
let concat = { x, y }: x + y;
in concat { x = "foo"; y = "bar"; }
```
## Conditionals
Conditionals look like this:
```nix
if e1 then e2 else e3
```
where *e1* is an expression that should evaluate to a Boolean value
(`true` or `false`).
## Assertions
Assertions are generally used to check that certain requirements on or
between features and dependencies hold. They look like this:
```nix
assert e1; e2
```
where *e1* is an expression that should evaluate to a Boolean value. If
it evaluates to `true`, *e2* is returned; otherwise expression
evaluation is aborted and a backtrace is printed.
Here is a Nix expression for the Subversion package that shows how
assertions can be used:.
```nix
{ localServer ? false
, httpServer ? false
, sslSupport ? false
, pythonBindings ? false
, javaSwigBindings ? false
, javahlBindings ? false
, stdenv, fetchurl
, openssl ? null, httpd ? null, db4 ? null, expat, swig ? null, j2sdk ? null
}:
assert localServer -> db4 != null; ①
assert httpServer -> httpd != null && httpd.expat == expat; ②
assert sslSupport -> openssl != null && (httpServer -> httpd.openssl == openssl); ③
assert pythonBindings -> swig != null && swig.pythonSupport;
assert javaSwigBindings -> swig != null && swig.javaSupport;
assert javahlBindings -> j2sdk != null;
stdenv.mkDerivation {
name = "subversion-1.1.1";
...
openssl = if sslSupport then openssl else null; ④
...
}
```
The points of interest are:
1. This assertion states that if Subversion is to have support for
local repositories, then Berkeley DB is needed. So if the Subversion
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
because in this configuration Subversion code ends up being linked
with Apache code, and if the Expat libraries do not match, a build-
or runtime link error or incompatibility might occur.
3. This assertion says that in order for Subversion to have SSL support
(so that it can access `https` URLs), an OpenSSL library must be
passed. Additionally, it says that *if* Apache support is enabled,
then Apache's OpenSSL should match Subversion's. (Note that if
Apache support is not enabled, we don't care about Apache's
OpenSSL.)
4. The conditional here is not really related to assertions, but is
worth pointing out: it ensures that if SSL support is disabled, then
the Subversion derivation is not dependent on OpenSSL, even if a
non-`null` value was passed. This prevents an unnecessary rebuild of
Subversion if OpenSSL changes.
## With-expressions
A *with-expression*,
```nix
with e1; e2
```
introduces the set *e1* into the lexical scope of the expression *e2*.
For instance,
```nix
let as = { x = "foo"; y = "bar"; };
in with as; x + y
```
evaluates to `"foobar"` since the `with` adds the `x` and `y` attributes
of `as` to the lexical scope in the expression `x + y`. The most common
use of `with` is in conjunction with the `import` function. E.g.,
```nix
with (import ./definitions.nix); ...
```
makes all attributes defined in the file `definitions.nix` available as
if they were defined locally in a `let`-expression.
The bindings introduced by `with` do not shadow bindings introduced by
other means, e.g.
```nix
let a = 3; in with { a = 1; }; let a = 4; in with { a = 2; }; ...
```
establishes the same scope as
```nix
let a = 1; in let a = 2; in let a = 3; in let a = 4; in ...
```
Variables coming from outer `with` expressions *are* shadowed:
```nix
with { a = "outer"; };
with { a = "inner"; };
a
```
Does evaluate to `"inner"`.
## Comments
- Inline comments start with `#` and run until the end of the line.
> **Example**
>
> ```nix
> # A number
> 2 # Equals 1 + 1
> ```
>
> ```console
> 2
> ```
- Block comments start with `/*` and run until the next occurrence of `*/`.
> **Example**
>
> ```nix
> /*
> Block comments
> can span multiple lines.
> */ "hello"
> ```
>
> ```console
> "hello"
> ```
This means that block comments cannot be nested.
> **Example**
>
> ```nix
> /* /* nope */ */ 1
> ```
>
> ```console
> error: syntax error, unexpected '*'
>
> at «string»:1:15:
>
> 1| /* /* nope */ *
> | ^
> ```
Consider escaping nested comments and unescaping them in post-processing.
> **Example**
>
> ```nix
> /* /* nested *\/ */ 1
> ```
>
> ```console
> 1
> ```

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@@ -1,120 +0,0 @@
# Data Types
Every value in the Nix language has one of the following types:
* [Integer](#type-int)
* [Float](#type-float)
* [Boolean](#type-bool)
* [String](#type-string)
* [Path](#type-path)
* [Null](#type-null)
* [Attribute set](#type-attrs)
* [List](#type-list)
* [Function](#type-function)
* [External](#type-external)
## Primitives
### Integer {#type-int}
An _integer_ in the Nix language is a signed 64-bit integer.
Non-negative integers can be expressed as [integer literals](syntax.md#number-literal).
Negative integers are created with the [arithmetic negation operator](./operators.md#arithmetic).
The function [`builtins.isInt`](builtins.md#builtins-isInt) can be used to determine if a value is an integer.
### Float {#type-float}
A _float_ in the Nix language is a 64-bit [IEEE 754](https://en.wikipedia.org/wiki/IEEE_754) floating-point number.
Most non-negative floats can be expressed as [float literals](syntax.md#number-literal).
Negative floats are created with the [arithmetic negation operator](./operators.md#arithmetic).
The function [`builtins.isFloat`](builtins.md#builtins-isFloat) can be used to determine if a value is a float.
### Boolean {#type-bool}
A _boolean_ in the Nix language is one of _true_ or _false_.
<!-- TODO: mention the top-level environment -->
These values are available as attributes of [`builtins`](builtins.md#builtins-builtins) as [`builtins.true`](builtins.md#builtins-true) and [`builtins.false`](builtins.md#builtins-false).
The function [`builtins.isBool`](builtins.md#builtins-isBool) can be used to determine if a value is a boolean.
### String {#type-string}
A _string_ in the Nix language is an immutable, finite-length sequence of bytes, along with a [string context](string-context.md).
Nix does not assume or support working natively with character encodings.
String values without string context can be expressed as [string literals](syntax.md#string-literal).
The function [`builtins.isString`](builtins.md#builtins-isString) can be used to determine if a value is a string.
### Path {#type-path}
A _path_ in the Nix language is an immutable, finite-length sequence of bytes starting with `/`, representing a POSIX-style, canonical file system path.
Path values are distinct from string values, even if they contain the same sequence of bytes.
Operations that produce paths will simplify the result as the standard C function [`realpath`] would, except that there is no symbolic link resolution.
[`realpath`]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/realpath.html
Paths are suitable for referring to local files, and are often preferable over strings.
- Path values do not contain trailing or duplicate slashes, `.`, or `..`.
- Relative path literals are automatically resolved relative to their [base directory].
- Tooling can recognize path literals and provide additional features, such as autocompletion, refactoring automation and jump-to-file.
[base directory]: @docroot@/glossary.md#gloss-base-directory
A file is not required to exist at a given path in order for that path value to be valid, but a path that is converted to a string with [string interpolation] or [string-and-path concatenation] must resolve to a readable file or directory which will be copied into the Nix store.
For instance, evaluating `"${./foo.txt}"` will cause `foo.txt` from the same directory to be copied into the Nix store and result in the string `"/nix/store/<hash>-foo.txt"`.
Operations such as [`import`] can also expect a path to resolve to a readable file or directory.
[string interpolation]: string-interpolation.md#interpolated-expression
[string-and-path concatenation]: operators.md#string-and-path-concatenation
[`import`]: builtins.md#builtins-import
> **Note**
>
> The Nix language assumes that all input files will remain _unchanged_ while evaluating a Nix expression.
> For example, assume you used a file path in an interpolated string during a `nix repl` session.
> Later in the same session, after having changed the file contents, evaluating the interpolated string with the file path again might not return a new [store path], since Nix might not re-read the file contents.
> Use `:r` to reset the repl as needed.
[store path]: @docroot@/store/store-path.md
Path values can be expressed as [path literals](syntax.md#path-literal).
The function [`builtins.isPath`](builtins.md#builtins-isPath) can be used to determine if a value is a path.
### Null {#type-null}
There is a single value of type _null_ in the Nix language.
<!-- TODO: mention the top-level environment -->
This value is available as an attribute on the [`builtins`](builtins.md#builtins-builtins) attribute set as [`builtins.null`](builtins.md#builtins-null).
## Compound values
### Attribute set {#type-attrs}
<!-- TODO(@rhendric, #10970): fill this out -->
An attribute set can be constructed with an [attribute set literal](syntax.md#attrs-literal).
The function [`builtins.isAttrs`](builtins.md#builtins-isAttrs) can be used to determine if a value is an attribute set.
### List {#type-list}
<!-- TODO(@rhendric, #10970): fill this out -->
A list can be constructed with a [list literal](syntax.md#list-literal).
The function [`builtins.isList`](builtins.md#builtins-isList) can be used to determine if a value is a list.
## Function {#type-function}
<!-- TODO(@rhendric, #10970): fill this out -->
A function can be constructed with a [function expression](syntax.md#functions).
The function [`builtins.isFunction`](builtins.md#builtins-isFunction) can be used to determine if a value is a function.
## External {#type-external}
An _external_ value is an opaque value created by a Nix [plugin](../command-ref/conf-file.md#conf-plugin-files).
Such a value can be substituted in Nix expressions but only created and used by plugin code.

View File

@@ -0,0 +1,280 @@
# Data Types
## Primitives
- <a id="type-string" href="#type-string">String</a>
*Strings* can be written in three ways.
The most common way is to enclose the string between double quotes,
e.g., `"foo bar"`. Strings can span multiple lines. The special
characters `"` and `\` and the character sequence `${` must be
escaped by prefixing them with a backslash (`\`). Newlines, carriage
returns and tabs can be written as `\n`, `\r` and `\t`,
respectively.
You can include the results of other expressions into a string by enclosing them in `${ }`, a feature known as [string interpolation].
[string interpolation]: ./string-interpolation.md
The second way to write string literals is as an *indented string*,
which is enclosed between pairs of *double single-quotes*, like so:
```nix
''
This is the first line.
This is the second line.
This is the third line.
''
```
This kind of string literal intelligently strips indentation from
the start of each line. To be precise, it strips from each line a
number of spaces equal to the minimal indentation of the string as a
whole (disregarding the indentation of empty lines). For instance,
the first and second line are indented two spaces, while the third
line is indented four spaces. Thus, two spaces are stripped from
each line, so the resulting string is
```nix
"This is the first line.\nThis is the second line.\n This is the third line.\n"
```
Note that the whitespace and newline following the opening `''` is
ignored if there is no non-whitespace text on the initial line.
Indented strings support [string interpolation].
Since `${` and `''` have special meaning in indented strings, you
need a way to quote them. `$` can be escaped by prefixing it with
`''` (that is, two single quotes), i.e., `''$`. `''` can be escaped
by prefixing it with `'`, i.e., `'''`. `$` removes any special
meaning from the following `$`. Linefeed, carriage-return and tab
characters can be written as `''\n`, `''\r`, `''\t`, and `''\`
escapes any other character.
Indented strings are primarily useful in that they allow multi-line
string literals to follow the indentation of the enclosing Nix
expression, and that less escaping is typically necessary for
strings representing languages such as shell scripts and
configuration files because `''` is much less common than `"`.
Example:
```nix
stdenv.mkDerivation {
...
postInstall =
''
mkdir $out/bin $out/etc
cp foo $out/bin
echo "Hello World" > $out/etc/foo.conf
${if enableBar then "cp bar $out/bin" else ""}
'';
...
}
```
Finally, as a convenience, *URIs* as defined in appendix B of
[RFC 2396](http://www.ietf.org/rfc/rfc2396.txt) can be written *as
is*, without quotes. For instance, the string
`"http://example.org/foo.tar.bz2"` can also be written as
`http://example.org/foo.tar.bz2`.
- <a id="type-number" href="#type-number">Number</a>
Numbers, which can be *integers* (like `123`) or *floating point*
(like `123.43` or `.27e13`).
See [arithmetic] and [comparison] operators for semantics.
[arithmetic]: ./operators.md#arithmetic
[comparison]: ./operators.md#comparison
- <a id="type-path" href="#type-path">Path</a>
*Paths* are distinct from strings and can be expressed by path literals such as `./builder.sh`.
Paths are suitable for referring to local files, and are often preferable over strings.
- Path values do not contain trailing slashes, `.` and `..`, as they are resolved when evaluating a path literal.
- Path literals are automatically resolved relative to their [base directory](@docroot@/glossary.md#gloss-base-directory).
- The files referred to by path values are automatically copied into the Nix store when used in a string interpolation or concatenation.
- Tooling can recognize path literals and provide additional features, such as autocompletion, refactoring automation and jump-to-file.
A path literal must contain at least one slash to be recognised as such.
For instance, `builder.sh` is not a path:
it's parsed as an expression that selects the attribute `sh` from the variable `builder`.
Path literals may also refer to absolute paths by starting with a slash.
> **Note**
>
> Absolute paths make expressions less portable.
> In the case where a function translates a path literal into an absolute path string for a configuration file, it is recommended to write a string literal instead.
> This avoids some confusion about whether files at that location will be used during evaluation.
> It also avoids unintentional situations where some function might try to copy everything at the location into the store.
If the first component of a path is a `~`, it is interpreted such that the rest of the path were relative to the user's home directory.
For example, `~/foo` would be equivalent to `/home/edolstra/foo` for a user whose home directory is `/home/edolstra`.
Path literals that start with `~` are not allowed in [pure](@docroot@/command-ref/conf-file.md#conf-pure-eval) evaluation.
Paths can be used in [string interpolation] and string concatenation.
For instance, evaluating `"${./foo.txt}"` will cause `foo.txt` from the same directory to be copied into the Nix store and result in the string `"/nix/store/<hash>-foo.txt"`.
Note that the Nix language assumes that all input files will remain _unchanged_ while evaluating a Nix expression.
For example, assume you used a file path in an interpolated string during a `nix repl` session.
Later in the same session, after having changed the file contents, evaluating the interpolated string with the file path again might not return a new [store path], since Nix might not re-read the file contents. Use `:r` to reset the repl as needed.
[store path]: @docroot@/store/store-path.md
Path literals can also include [string interpolation], besides being [interpolated into other expressions].
[interpolated into other expressions]: ./string-interpolation.md#interpolated-expressions
At least one slash (`/`) must appear *before* any interpolated expression for the result to be recognized as a path.
`a.${foo}/b.${bar}` is a syntactically valid number division operation.
`./a.${foo}/b.${bar}` is a path.
[Lookup path](./constructs/lookup-path.md) literals such as `<nixpkgs>` also resolve to path values.
- <a id="type-boolean" href="#type-boolean">Boolean</a>
*Booleans* with values `true` and `false`.
- <a id="type-null" href="#type-null">Null</a>
The null value, denoted as `null`.
## List
Lists are formed by enclosing a whitespace-separated list of values
between square brackets. For example,
```nix
[ 123 ./foo.nix "abc" (f { x = y; }) ]
```
defines a list of four elements, the last being the result of a call to
the function `f`. Note that function calls have to be enclosed in
parentheses. If they had been omitted, e.g.,
```nix
[ 123 ./foo.nix "abc" f { x = y; } ]
```
the result would be a list of five elements, the fourth one being a
function and the fifth being a set.
Note that lists are only lazy in values, and they are strict in length.
Elements in a list can be accessed using [`builtins.elemAt`](./builtins.md#builtins-elemAt).
## Attribute Set
An attribute set is a collection of name-value-pairs (called *attributes*) enclosed in curly brackets (`{ }`).
An attribute name can be an identifier or a [string](#string).
An identifier must start with a letter (`a-z`, `A-Z`) or underscore (`_`), and can otherwise contain letters (`a-z`, `A-Z`), numbers (`0-9`), underscores (`_`), apostrophes (`'`), or dashes (`-`).
> **Syntax**
>
> *name* = *identifier* | *string* \
> *identifier* ~ `[a-zA-Z_][a-zA-Z0-9_'-]*`
Names and values are separated by an equal sign (`=`).
Each value is an arbitrary expression terminated by a semicolon (`;`).
> **Syntax**
>
> *attrset* = `{` [ *name* `=` *expr* `;` ]... `}`
Attributes can appear in any order.
An attribute name may only occur once.
Example:
```nix
{
x = 123;
text = "Hello";
y = f { bla = 456; };
}
```
This defines a set with attributes named `x`, `text`, `y`.
Attributes can be accessed with the [`.` operator](./operators.md#attribute-selection).
Example:
```nix
{ a = "Foo"; b = "Bar"; }.a
```
This evaluates to `"Foo"`.
It is possible to provide a default value in an attribute selection using the `or` keyword.
Example:
```nix
{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"
```
```nix
{ a = "Foo"; b = "Bar"; }.c.d.e.f.g or "Xyzzy"
```
will both evaluate to `"Xyzzy"` because there is no `c` attribute in the set.
You can use arbitrary double-quoted strings as attribute names:
```nix
{ "$!@#?" = 123; }."$!@#?"
```
```nix
let bar = "bar"; in
{ "foo ${bar}" = 123; }."foo ${bar}"
```
Both will evaluate to `123`.
Attribute names support [string interpolation]:
```nix
let bar = "foo"; in
{ foo = 123; }.${bar}
```
```nix
let bar = "foo"; in
{ ${bar} = 123; }.foo
```
Both will evaluate to `123`.
In the special case where an attribute name inside of a set declaration
evaluates to `null` (which is normally an error, as `null` cannot be coerced to
a string), that attribute is simply not added to the set:
```nix
{ ${if foo then "bar" else null} = true; }
```
This will evaluate to `{}` if `foo` evaluates to `false`.
A set that has a `__functor` attribute whose value is callable (i.e. is
itself a function or a set with a `__functor` attribute whose value is
callable) can be applied as if it were a function, with the set itself
passed in first , e.g.,
```nix
let add = { __functor = self: x: x + self.x; };
inc = add // { x = 1; };
in inc 1
```
evaluates to `2`. This can be used to attach metadata to a function
without the caller needing to treat it specially, or to implement a form
of object-oriented programming, for example.

View File

@@ -14,6 +14,6 @@ Derivations are serialised in one of the following formats:
DrvWithVersion(<version-string>, ...)
```
The only `version-string`s that are in use today are for [experimental features](@docroot@/development/experimental-features.md):
The only `version-string`s that are in use today are for [experimental features](@docroot@/contributing/experimental-features.md):
- `"xp-dyn-drv"` for the [`dynamic-derivations`](@docroot@/development/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.
- `"xp-dyn-drv"` for the [`dynamic-derivations`](@docroot@/contributing/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.

View File

@@ -3,7 +3,7 @@
> **Warning**
>
> This JSON format is currently
> [**experimental**](@docroot@/development/experimental-features.md#xp-feature-nix-command)
> [**experimental**](@docroot@/contributing/experimental-features.md#xp-feature-nix-command)
> and subject to change.
The JSON serialization of a

View File

@@ -3,7 +3,7 @@
> **Warning**
>
> This JSON format is currently
> [**experimental**](@docroot@/development/experimental-features.md#xp-feature-nix-command)
> [**experimental**](@docroot@/contributing/experimental-features.md#xp-feature-nix-command)
> and subject to change.
Info about a [store object].
@@ -24,11 +24,9 @@ Info about a [store object].
An array of [store paths][store path], possibly including this one.
* `ca`:
* `ca` (optional):
If the store object is [content-addressed],
this is the content address of this store object's file system object, used to compute its store path.
Otherwise (i.e. if it is [input-addressed]), this is `null`.
Content address of this store object's file system object, used to compute its store path.
[store path]: @docroot@/store/store-path.md
[file system object]: @docroot@/store/file-system-object.md
@@ -39,30 +37,28 @@ Info about a [store object].
These are not intrinsic properties of the store object.
In other words, the same store object residing in different store could have different values for these properties.
* `deriver`:
* `deriver` (optional):
If known, the path to the [derivation] from which this store object was produced.
Otherwise `null`.
The path to the [derivation] from which this store object is produced.
[derivation]: @docroot@/glossary.md#gloss-store-derivation
* `registrationTime` (optional):
If known, when this derivation was added to the store.
Otherwise `null`.
When this derivation was added to the store.
* `ultimate`:
* `ultimate` (optional):
Whether this store object is trusted because we built it ourselves, rather than substituted a build product from elsewhere.
* `signatures`:
* `signatures` (optional):
Signatures claiming that this store object is what it claims to be.
Not relevant for [content-addressed] store objects,
but useful for [input-addressed] store objects.
[content-addressed]: @docroot@/store/store-object/content-address.md
[input-addressed]: @docroot@/glossary.md#gloss-input-addressed-store-object
[content-addressed]: @docroot@/glossary.md#gloss-content-addressed-store-object
[input-addressed]: @docroot@/glossary.md#gloss-input-addressed-store-object
### `.narinfo` extra fields

View File

@@ -29,7 +29,7 @@ regular = [ str("executable"), str("") ], str("contents"), str(contents);
symlink = str("target"), str(target);
(* side condition: directory entries must be ordered by their names *)
directory = { directory-entry };
directory = str("type"), str("directory") { directory-entry };
directory-entry = str("entry"), str("("), str("name"), str(name), str("node"), nar-obj, str(")");
```

View File

@@ -41,30 +41,4 @@ Link: <https://example.org/hello/442793d9ec0584f6a6e82fa253850c8085bb150a.tar.gz
For tarball flakes, the value of the `lastModified` flake attribute is
defined as the timestamp of the newest file inside the tarball.
## Gitea and Forgejo support
This protocol is supported by Gitea since v1.22.1 and by Forgejo since v7.0.4/v8.0.0 and can be used with the following flake URL schema:
```
https://<domain name>/<owner>/<repo>/archive/<reference or revison>.tar.gz
```
> **Example**
>
>
> ```nix
> # flake.nix
> {
> inputs = {
> foo.url = "https://gitea.example.org/some-person/some-flake/archive/main.tar.gz";
> bar.url = "https://gitea.example.org/some-other-person/other-flake/archive/442793d9ec0584f6a6e82fa253850c8085bb150a.tar.gz";
> qux = {
> url = "https://forgejo.example.org/another-person/some-non-flake-repo/archive/development.tar.gz";
> flake = false;
> };
> };
> outputs = { foo, bar, qux }: { /* ... */ };
> }
```
[Nix Archive]: @docroot@/store/file-system-object/content-address.md#serial-nix-archive

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