Merge pull request #36 from DeterminateSystems/sync-2.24.2

Sync with Nix 2.24.2

.version

@@ -1 +1 @@
-2.24.0
+2.24.2

CONTRIBUTING.md

@@ -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://nixos.org/manual/nix/unstable/contributing/hacking.html) for information on building Nix and running its tests.
+3. Check the [Nix reference manual](https://nix.dev/manual/nix/development/development/building.html) for information on building Nix and running its tests.
 
-   For contributions to the command line interface, please check the [CLI guidelines](https://nixos.org/manual/nix/unstable/contributing/cli-guideline.html).
+   For contributions to the command line interface, please check the [CLI guidelines](https://nix.dev/manual/nix/development/development/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://nixos.org/manual/nix/stable/contributing/hacking#add-a-release-note)
+   - [ ] New feature or incompatible change: [add a release note](https://nix.dev/manual/nix/development/development/contributing.html#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://nixos.org/manual/nix/unstable/contributing/hacking.html).
+For larger changes see the [Nix reference manual](https://nix.dev/manual/nix/development/development/contributing.html).
 
 ## Getting help
 

Makefile

@@ -54,6 +54,7 @@ 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 \
@@ -92,7 +93,7 @@ ifdef HOST_WINDOWS
   GLOBAL_LDFLAGS += -Wl,--export-all-symbols
 endif
 
-GLOBAL_CXXFLAGS += -g -Wall -Wdeprecated-copy -Wignored-qualifiers -Wimplicit-fallthrough -Werror=unused-result -include $(buildprefix)config.h -std=c++2a -I src
+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
 
 # Include the main lib, causing rules to be defined
 

README.md

@@ -4,19 +4,18 @@
 [![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://nixos.org/nix/manual)
+management reliable and reproducible. Please refer to the [Nix manual](https://nix.dev/reference/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://nixos.org/nix/manual).
+Full reference documentation can be found in the [Nix manual](https://nix.dev/reference/nix-manual).
 
 ## Building and developing
 
-See our [Hacking guide](https://nixos.org/manual/nix/unstable/contributing/hacking.html) in our manual for instruction on how to
+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).
- set up a development environment and build Nix from source.
 
 ## Contributing
 

build-utils-meson/diagnostics/meson.build

@@ -1,13 +1,11 @@
 add_project_arguments(
-  '-Wno-deprecated-declarations',
+  '-Wdeprecated-copy',
-  '-Wimplicit-fallthrough',
+  '-Werror=suggest-override',
   '-Werror=switch',
   '-Werror=switch-enum',
   '-Werror=unused-result',
-  '-Wdeprecated-copy',
   '-Wignored-qualifiers',
-  # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
+  '-Wimplicit-fallthrough',
-  # at ~1% overhead in `nix search`.
+  '-Wno-deprecated-declarations',
-  #
   language : 'cpp',
 )

configure.ac

@@ -340,13 +340,6 @@ 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]]),

doc/manual/generate-builtins.nix

@@ -12,7 +12,7 @@ let
       experimentalNotice = optionalString (experimental-feature != null) ''
         > **Note**
         >
-        > This function is only available if the [`${experimental-feature}` experimental feature](@docroot@/contributing/experimental-features.md#xp-feature-${experimental-feature}) is enabled.
+        > This function is only available if the [`${experimental-feature}` experimental feature](@docroot@/development/experimental-features.md#xp-feature-${experimental-feature}) is enabled.
         >
         > For example, include the following in [`nix.conf`](@docroot@/command-ref/conf-file.md):
         >

doc/manual/generate-settings.nix

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

doc/manual/generate-store-info.nix

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

doc/manual/generate-xp-features-shortlist.nix

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

doc/manual/local.mk

@@ -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 $(d)/src/contributing/experimental-feature-descriptions.md
+$(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/development/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 > $@.tmp
 	@mv $@.tmp $@
 
-$(d)/src/contributing/experimental-feature-descriptions.md: $(d)/xp-features.json $(d)/utils.nix $(d)/generate-xp-features.nix $(doc_nix)
+$(d)/src/development/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 $@
@@ -207,11 +207,11 @@ doc/manual/generated/man1/nix3-manpages: $(d)/src/command-ref/new-cli
 	done
 	@touch $@
 
-# the `! -name 'contributing.md'` filter excludes the one place where
+# the `! -name 'documentation.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/contributing/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/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
 	$(trace-gen) \
 		tmp="$$(mktemp -d)"; \
 		cp -r doc/manual "$$tmp"; \

doc/manual/redirects.js

@@ -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": "contributing/hacking.html",
+    "chap-hacking": "development/building.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",
@@ -350,7 +350,7 @@ const redirects = {
     "macos": "uninstall.html#macos",
     "uninstalling": "uninstall.html",
   },
-  "contributing/hacking.html": {
+  "development/building.html": {
     "nix-with-flakes": "#building-nix-with-flakes",
     "classic-nix": "#building-nix",
     "running-tests": "testing.html#running-tests",
@@ -361,7 +361,12 @@ 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": "#characterisation-testing-unit",
+    "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",
   },
   "glossary.html": {
     "gloss-local-store": "store/types/local-store.html",

doc/manual/rl-next/drop-vendored-toml11.md

@@ -1,6 +0,0 @@
----
-synopsis: Stop vendoring toml11
----
-
-We don't apply any patches to it, and vendoring it locks users into
-bugs (it hasn't been updated since its introduction in late 2021).

doc/manual/rl-next/harden-user-sandboxing.md

@@ -1,7 +0,0 @@
----
-synopsis: Harden the user sandboxing
-significance: significant
-issues:
----
-
-The build directory has been hardened against interference with the outside world by nesting it inside another directory owned by (and only readable by) the daemon user.

doc/manual/rl-next/nix-shell-looks-for-shell-nix.md

@@ -1,28 +0,0 @@
----
-synopsis: "`nix-shell <directory>` looks for `shell.nix`"
-significance: significant
-issues:
-- 496
-- 2279
-- 4529
-- 5431
-- 11053
-prs:
-- 11057
----
-
-`nix-shell $x` now looks for `$x/shell.nix` when `$x` resolves to a directory.
-
-Although this might be seen as a breaking change, its primarily interactive usage makes it a minor issue.
-This adjustment addresses a commonly reported problem.
-
-This also applies to `nix-shell` shebang scripts. Consider the following example:
-
-```shell
-#!/usr/bin/env nix-shell
-#!nix-shell -i bash
-```
-
-This will now load `shell.nix` from the script's directory, if it exists; `default.nix` otherwise.
-
-The old behavior can be opted into by setting the option [`nix-shell-always-looks-for-shell-nix`](@docroot@/command-ref/conf-file.md#conf-nix-shell-always-looks-for-shell-nix) to `false`.

doc/manual/rl-next/repl-doc-renders-doc-comments.md

@@ -1,53 +0,0 @@
----
-synopsis: "`nix-repl`'s `:doc` shows documentation comments"
-significance: significant
-issues:
-- 3904
-- 10771
-prs:
-- 1652
-- 9054
-- 11072
----
-
-`nix repl` has a `:doc` command that previously only rendered documentation for internally defined functions.
-This feature has been extended to also render function documentation comments, in accordance with [RFC 145].
-
-Example:
-
-```
-nix-repl> :doc lib.toFunction
-Function toFunction
-    … defined at /home/user/h/nixpkgs/lib/trivial.nix:1072:5
-
-    Turns any non-callable values into constant functions. Returns
-    callable values as is.
-
-Inputs
-
-    v
-
-      : Any value
-
-Examples
-
-    :::{.example}
-
-## lib.trivial.toFunction usage example
-
-      | nix-repl> lib.toFunction 1 2
-      | 1
-      | 
-      | nix-repl> lib.toFunction (x: x + 1) 2
-      | 3
-
-    :::
-```
-
-Known limitations:
-- It does not render documentation for "formals", such as `{ /** the value to return */ x, ... }: x`.
-- Some extensions to markdown are not yet supported, as you can see in the example above.
-
-We'd like to acknowledge Yingchi Long for proposing a proof of concept for this functionality in [#9054](https://github.com/NixOS/nix/pull/9054), as well as @sternenseemann and Johannes Kirschbauer for their contributions, proposals, and their work on [RFC 145].
-
-[RFC 145]: https://github.com/NixOS/rfcs/pull/145

doc/manual/src/SUMMARY.md.in

@@ -28,6 +28,7 @@
   - [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)
     - [String interpolation](language/string-interpolation.md)
     - [Lookup path](language/constructs/lookup-path.md)
@@ -116,16 +117,18 @@
   - [Flake Schemas](protocols/flake-schemas.md)
 - [C API](c-api.md)
 - [Glossary](glossary.md)
-- [Contributing](contributing/index.md)
+- [Development](development/index.md)
-  - [Hacking](contributing/hacking.md)
+  - [Building](development/building.md)
-  - [Testing](contributing/testing.md)
+  - [Testing](development/testing.md)
-  - [Documentation](contributing/documentation.md)
+  - [Documentation](development/documentation.md)
-  - [Experimental Features](contributing/experimental-features.md)
+  - [CLI guideline](development/cli-guideline.md)
-  - [CLI guideline](contributing/cli-guideline.md)
+  - [JSON guideline](development/json-guideline.md)
-  - [JSON guideline](contributing/json-guideline.md)
+  - [C++ style guide](development/cxx.md)
-  - [C++ style guide](contributing/cxx.md)
+  - [Experimental Features](development/experimental-features.md)
+  - [Contributing](development/contributing.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)

doc/manual/src/_redirects

@@ -20,7 +20,15 @@
 
 /command-ref/command-ref /command-ref 301!
 
-/contributing/contributing /contributing 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!
 
 /expressions/expression-language /language/ 301!
 /expressions/language-constructs /language/constructs 301!

doc/manual/src/c-api.md

@@ -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](contributing/documentation.md#c-api-documentation), including how to build it locally.
+- [Contributing C API Documentation](development/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

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

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

doc/manual/src/command-ref/experimental-commands.md

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

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

@@ -297,3 +297,8 @@ 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.

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

@@ -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@/contributing/experimental-features.md#xp-feature-ca-derivations
+[content-addressed derivations]: @docroot@/development/experimental-features.md#xp-feature-ca-derivations
 [Nix database]: @docroot@/glossary.md#gloss-nix-database
 
 The resulting paths are printed on standard output.

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

@@ -187,11 +187,12 @@ 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`](#opt-I)</span> *path*
+- <span id="opt-I">[`-I` / `--include`](#opt-I)</span> *path*
 
-  Add an entry to the [Nix expression search path](@docroot@/command-ref/conf-file.md#conf-nix-path).
+  Add an entry to the list of search paths used to resolve [lookup paths](@docroot@/language/constructs/lookup-path.md).
   This option may be given multiple times.
-  Paths added through `-I` take precedence over [`NIX_PATH`](@docroot@/command-ref/env-common.md#env-NIX_PATH).
+
+  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).
 
 - <span id="opt-option">[`--option`](#opt-option)</span> *name* *value*
 

doc/manual/src/development/building.md

@@ -1,18 +1,4 @@
-# Hacking
+## Building Nix
-
-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
-```
-
-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 instructions]: ../installation/index.md
-
-## Building Nix with flakes
 
 To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
 
@@ -61,50 +47,6 @@ $ 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`.
@@ -274,81 +216,3 @@ 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.

doc/manual/src/development/contributing.md

@@ -0,0 +1,79 @@
+# 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.

doc/manual/src/development/documentation.md

@@ -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](./hacking.md) and run:
+To build the manual incrementally, [enter the development shell](./building.md) and run:
 
 ```console
 make manual-html-open -j $NIX_BUILD_CORES

doc/manual/src/development/index.md

@@ -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](./hacking.md) and consider [making improvements to documentation](./documentation.md).
+If you're not sure where to start, try to [compile Nix from source](./building.md) and consider [making improvements to documentation](./documentation.md).

doc/manual/src/glossary.md

@@ -168,7 +168,7 @@
 
 - [impure derivation]{#gloss-impure-derivation}
 
-  [An experimental feature](#@docroot@/contributing/experimental-features.md#xp-feature-impure-derivations) that allows derivations to be explicitly marked as impure,
+  [An experimental feature](#@docroot@/development/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}
@@ -353,7 +353,7 @@
   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@/contributing/experimental-features.md).
+  See the contribution guide on the [purpose and lifecycle of experimental feaures](@docroot@/development/experimental-features.md).
 
 
 [Nix language]: ./language/index.md

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

@@ -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](../contributing/hacking.md#platforms)
+- Choose a [version](https://releases.nixos.org/?prefix=nix/) and [system type](../development/building.md#platforms)
 - Download and unpack the tarball
 - Run the installer
 

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

@@ -113,7 +113,7 @@ Derivations can declare some infrequently used optional attributes.
     > `nix-build`.
 
     If the [`configurable-impure-env` experimental
-    feature](@docroot@/contributing/experimental-features.md#xp-feature-configurable-impure-env)
+    feature](@docroot@/development/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)
@@ -226,7 +226,7 @@ Derivations can declare some infrequently used optional attributes.
   - [`__contentAddressed`]{#adv-attr-__contentAddressed}
 
     > **Warning**
-    > This attribute is part of an [experimental feature](@docroot@/contributing/experimental-features.md).
+    > This attribute is part of an [experimental feature](@docroot@/development/experimental-features.md).
     >
     > To use this attribute, you must enable the
     > [`ca-derivations`][xp-feature-ca-derivations] experimental feature.
@@ -370,6 +370,6 @@ 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@/contributing/experimental-features.md#xp-feature-ca-derivations
+[xp-feature-ca-derivations]: @docroot@/development/experimental-features.md#xp-feature-ca-derivations
-[xp-feature-dynamic-derivations]: @docroot@/contributing/experimental-features.md#xp-feature-dynamic-derivations
+[xp-feature-dynamic-derivations]: @docroot@/development/experimental-features.md#xp-feature-dynamic-derivations
-[xp-feature-git-hashing]: @docroot@/contributing/experimental-features.md#xp-feature-git-hashing
+[xp-feature-git-hashing]: @docroot@/development/experimental-features.md#xp-feature-git-hashing

doc/manual/src/language/identifiers.md

@@ -0,0 +1,50 @@
+# 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.

doc/manual/src/language/operators.md

@@ -26,13 +26,17 @@
 | 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 <!-- TODO(@rhendric, #10970): rationalize this -->
+[number]: ./types.md#type-float
 [list]: ./types.md#list
 [attribute set]: ./types.md#attribute-set
 
+<!-- TODO(@rhendric, #10970): ^ rationalize number -> int/float -->
+
 ## Attribute selection
 
 > **Syntax**
@@ -42,12 +46,6 @@
 Select the attribute denoted by attribute path *attrpath* from [attribute set] *attrset*.
 If the attribute doesn’t exist, return the *expr* after `or` if provided, otherwise abort evaluation.
 
-An attribute path is a dot-separated list of [attribute names](./types.md#attribute-set).
-
-> **Syntax**
->
-> *attrpath* = *name* [ `.` *name* ]...
-
 [Attribute selection]: #attribute-selection
 
 ## Has attribute
@@ -182,3 +180,34 @@ 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

doc/manual/src/language/syntax.md

@@ -190,18 +190,13 @@ This section covers syntax and semantics of the Nix language.
 
 ### Path {#path-literal}
 
-  *Paths* are distinct from strings and can be expressed by path literals such as `./builder.sh`.
+  *Paths* 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 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**
@@ -215,15 +210,6 @@ This section covers syntax and semantics of the Nix language.
   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
@@ -261,37 +247,76 @@ Elements in a list can be accessed using [`builtins.elemAt`](./builtins.md#built
 
 ## Attribute Set {#attrs-literal}
 
-An attribute set is a collection of name-value-pairs (called *attributes*) enclosed in curly brackets (`{ }`).
+An attribute set is a collection of name-value-pairs called *attributes*.
 
-An attribute name can be an identifier or a [string](#string).
+Attribute sets are written enclosed in curly brackets (`{ }`).
-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 (`-`).
+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**
 >
-> *name* = *identifier* | *string* \
+> *attrset* → `{` { *name* `=` *expr* `;` } `}`
-> *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.
+An attribute name may only occur once in each attribute set.
 
-Example:
+> **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; };
+> }
+> ```
 
-```nix
+Attributes in nested attribute sets can be written using *attribute paths*.
-{
-  x = 123;
-  text = "Hello";
-  y = f { bla = 456; };
-}
-```
 
-This defines a set with attributes named `x`, `text`, `y`.
+> **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).
 

doc/manual/src/language/types.md

@@ -50,8 +50,37 @@ The function [`builtins.isString`](builtins.md#builtins-isString) can be used to
 
 ### Path {#type-path}
 
-<!-- TODO(@rhendric, #10970): Incorporate content from syntax.md#path-literal -->
+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}

doc/manual/src/protocols/derivation-aterm.md

@@ -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@/contributing/experimental-features.md):
+  The only `version-string`s that are in use today are for [experimental features](@docroot@/development/experimental-features.md):
 
-  - `"xp-dyn-drv"` for the [`dynamic-derivations`](@docroot@/contributing/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.
+  - `"xp-dyn-drv"` for the [`dynamic-derivations`](@docroot@/development/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.

doc/manual/src/protocols/tarball-fetcher.md

@@ -41,4 +41,30 @@ 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

doc/manual/src/release-notes/rl-2.18.md

@@ -13,7 +13,7 @@
 
 - The `discard-references` feature has been stabilized.
   This means that the
-  [unsafeDiscardReferences](@docroot@/contributing/experimental-features.md#xp-feature-discard-references)
+  [unsafeDiscardReferences](@docroot@/development/experimental-features.md#xp-feature-discard-references)
   attribute is no longer guarded by an experimental flag and can be used
   freely.
 
@@ -21,7 +21,7 @@
   This only affects `nix-build --json` when "building" non-derivation things like fetched sources, which is a no-op.
 
 - A new builtin [`outputOf`](@docroot@/language/builtins.md#builtins-outputOf) has been added.
-  It is part of the [`dynamic-derivations`](@docroot@/contributing/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.
+  It is part of the [`dynamic-derivations`](@docroot@/development/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.
 
 - Flake follow paths at depths greater than 2 are now handled correctly, preventing "follows a non-existent input" errors.
 

doc/manual/src/release-notes/rl-2.19.md

@@ -17,8 +17,8 @@
 
 - `nix-shell` shebang lines now support single-quoted arguments.
 
-- `builtins.fetchTree` is now its own experimental feature, [`fetch-tree`](@docroot@/contributing/experimental-features.md#xp-fetch-tree).
+- `builtins.fetchTree` is now its own experimental feature, [`fetch-tree`](@docroot@/development/experimental-features.md#xp-fetch-tree).
-  This allows stabilising it independently of the rest of what is encompassed by [`flakes`](@docroot@/contributing/experimental-features.md#xp-fetch-tree).
+  This allows stabilising it independently of the rest of what is encompassed by [`flakes`](@docroot@/development/experimental-features.md#xp-fetch-tree).
 
 - The interface for creating and updating lock files has been overhauled:
 
@@ -33,7 +33,7 @@
   - The flake-specific flags `--recreate-lock-file` and `--update-input` have been removed from all commands operating on installables.
     They are superceded by `nix flake update`.
 
-- Commit signature verification for the [`builtins.fetchGit`](@docroot@/language/builtins.md#builtins-fetchGit) is added as the new [`verified-fetches` experimental feature](@docroot@/contributing/experimental-features.md#xp-feature-verified-fetches).
+- Commit signature verification for the [`builtins.fetchGit`](@docroot@/language/builtins.md#builtins-fetchGit) is added as the new [`verified-fetches` experimental feature](@docroot@/development/experimental-features.md#xp-feature-verified-fetches).
 
 - [`nix path-info --json`](@docroot@/command-ref/new-cli/nix3-path-info.md)
   (experimental) now returns a JSON map rather than JSON list.

doc/manual/src/release-notes/rl-2.23.md

@@ -14,7 +14,7 @@
 
 - Modify `nix derivation {add,show}` JSON format [#9866](https://github.com/NixOS/nix/issues/9866) [#10722](https://github.com/NixOS/nix/pull/10722)
 
-  The JSON format for derivations has been slightly revised to better conform to our [JSON guidelines](@docroot@/contributing/cli-guideline.md#returning-future-proof-json).
+  The JSON format for derivations has been slightly revised to better conform to our [JSON guidelines](@docroot@/development/cli-guideline.md#returning-future-proof-json).
   In particular, the hash algorithm and content addressing method of content-addresed derivation outputs are now separated into two fields `hashAlgo` and `method`,
   rather than one field with an arcane `:`-separated format.
 
@@ -89,7 +89,7 @@
   This makes records of this sort more self-describing, and easier to consume programmatically.
 
   We will follow this design principle going forward;
-  the [JSON guidelines](@docroot@/contributing/json-guideline.md) in the contributing section have been updated accordingly.
+  the [JSON guidelines](@docroot@/development/json-guideline.md) in the contributing section have been updated accordingly.
 
 - Large path warnings [#10661](https://github.com/NixOS/nix/pull/10661)
 

doc/manual/src/release-notes/rl-2.24.md

@@ -0,0 +1,324 @@
+# Release 2.24.0 (2024-07-31)
+
+### Significant changes
+
+- Harden user sandboxing
+
+  The build directory has been hardened against interference with the outside world by nesting it inside another directory owned by (and only readable by) the daemon user.
+
+  This is a low severity security fix, [CVE-2024-38531](https://www.cve.org/CVERecord?id=CVE-2024-38531).
+
+  Credit: [**@alois31**](https://github.com/alois31), [**Linus Heckemann (@lheckemann)**](https://github.com/lheckemann)
+  Co-authors: [**@edolstra**](https://github.com/edolstra)
+
+- `nix-shell <directory>` looks for `shell.nix` [#496](https://github.com/NixOS/nix/issues/496) [#2279](https://github.com/NixOS/nix/issues/2279) [#4529](https://github.com/NixOS/nix/issues/4529) [#5431](https://github.com/NixOS/nix/issues/5431) [#11053](https://github.com/NixOS/nix/issues/11053) [#11057](https://github.com/NixOS/nix/pull/11057)
+
+  `nix-shell $x` now looks for `$x/shell.nix` when `$x` resolves to a directory.
+
+  Although this might be seen as a breaking change, its primarily interactive usage makes it a minor issue.
+  This adjustment addresses a commonly reported problem.
+
+  This also applies to `nix-shell` shebang scripts. Consider the following example:
+
+  ```shell
+  #!/usr/bin/env nix-shell
+  #!nix-shell -i bash
+  ```
+
+  This will now load `shell.nix` from the script's directory, if it exists; `default.nix` otherwise.
+
+  The old behavior can be opted into by setting the option [`nix-shell-always-looks-for-shell-nix`](@docroot@/command-ref/conf-file.md#conf-nix-shell-always-looks-for-shell-nix) to `false`.
+
+  Author: [**Robert Hensing (@roberth)**](https://github.com/roberth)
+
+- `nix-repl`'s `:doc` shows documentation comments [#3904](https://github.com/NixOS/nix/issues/3904) [#10771](https://github.com/NixOS/nix/issues/10771) [#1652](https://github.com/NixOS/nix/pull/1652) [#9054](https://github.com/NixOS/nix/pull/9054) [#11072](https://github.com/NixOS/nix/pull/11072)
+
+  `nix repl` has a `:doc` command that previously only rendered documentation for internally defined functions.
+  This feature has been extended to also render function documentation comments, in accordance with [RFC 145].
+
+  Example:
+
+  ```
+  nix-repl> :doc lib.toFunction
+  Function toFunction
+      … defined at /home/user/h/nixpkgs/lib/trivial.nix:1072:5
+
+      Turns any non-callable values into constant functions. Returns
+      callable values as is.
+
+  Inputs
+
+      v
+
+        : Any value
+
+  Examples
+
+      :::{.example}
+
+  ## lib.trivial.toFunction usage example
+
+        | nix-repl> lib.toFunction 1 2
+        | 1
+        |
+        | nix-repl> lib.toFunction (x: x + 1) 2
+        | 3
+
+      :::
+  ```
+
+  Known limitations:
+  - It does not render documentation for "formals", such as `{ /** the value to return */ x, ... }: x`.
+  - Some extensions to markdown are not yet supported, as you can see in the example above.
+
+  We'd like to acknowledge [Yingchi Long (@inclyc)](https://github.com/inclyc) for proposing a proof of concept for this functionality in [#9054](https://github.com/NixOS/nix/pull/9054), as well as [@sternenseemann](https://github.com/sternenseemann) and [Johannes Kirschbauer (@hsjobeki)](https://github.com/hsjobeki) for their contributions, proposals, and their work on [RFC 145].
+
+  Author: [**Robert Hensing (@roberth)**](https://github.com/roberth)
+
+  [RFC 145]: https://github.com/NixOS/rfcs/pull/145
+
+### Other changes
+
+- Solve `cached failure of attribute X` [#9165](https://github.com/NixOS/nix/issues/9165) [#10513](https://github.com/NixOS/nix/issues/10513) [#10564](https://github.com/NixOS/nix/pull/10564)
+
+  This eliminates all "cached failure of attribute X" messages by forcing evaluation of the original value when needed to show the exception to the user. This enhancement improves error reporting by providing the underlying message and stack trace.
+
+  Author: [**Eelco Dolstra (@edolstra)**](https://github.com/edolstra)
+
+- Run the flake regressions test suite [#10603](https://github.com/NixOS/nix/pull/10603)
+
+  This update introduces a GitHub action to run a subset of the [flake regressions test suite](https://github.com/NixOS/flake-regressions), which includes 259 flakes with their expected evaluation results. Currently, the action runs the first 25 flakes due to the full test suite's extensive runtime. A manually triggered action may be implemented later to run the entire test suite.
+
+  Author: [**Eelco Dolstra (@edolstra)**](https://github.com/edolstra)
+
+- Support unit prefixes in configuration settings [#10668](https://github.com/NixOS/nix/pull/10668)
+
+  Configuration settings in Nix now support unit prefixes, allowing for more intuitive and readable configurations. For example, you can now specify [`--min-free 1G`](@docroot@/command-ref/opt-common.md#opt-min-free) to set the minimum free space to 1 gigabyte.
+
+  This enhancement was extracted from [#7851](https://github.com/NixOS/nix/pull/7851) and is also useful for PR [#10661](https://github.com/NixOS/nix/pull/10661).
+
+  Author: [**Eelco Dolstra (@edolstra)**](https://github.com/edolstra)
+
+- `nix build`: show all FOD errors with `--keep-going` [#10734](https://github.com/NixOS/nix/pull/10734)
+
+  The [`nix build`](@docroot@/command-ref/new-cli/nix3-build.md) command has been updated to improve the behavior of the [`--keep-going`] flag. Now, when `--keep-going` is used, all hash-mismatch errors of failing fixed-output derivations (FODs) are displayed, similar to the behavior for other build failures. This enhancement ensures that all relevant build errors are shown, making it easier for users to update multiple derivations at once or to diagnose and fix issues.
+
+  Author: [**Jörg Thalheim (@Mic92)**](https://github.com/Mic92), [**Maximilian Bosch (@Ma27)**](https://github.com/Ma27)
+
+  [`--keep-going`](@docroot@/command-ref/opt-common.md#opt-keep-going)
+
+- Build with Meson [#2503](https://github.com/NixOS/nix/issues/2503) [#10378](https://github.com/NixOS/nix/pull/10378) [#10855](https://github.com/NixOS/nix/pull/10855) [#10904](https://github.com/NixOS/nix/pull/10904) [#10908](https://github.com/NixOS/nix/pull/10908) [#10914](https://github.com/NixOS/nix/pull/10914) [#10933](https://github.com/NixOS/nix/pull/10933) [#10936](https://github.com/NixOS/nix/pull/10936) [#10954](https://github.com/NixOS/nix/pull/10954) [#10955](https://github.com/NixOS/nix/pull/10955) [#10963](https://github.com/NixOS/nix/pull/10963) [#10967](https://github.com/NixOS/nix/pull/10967) [#10973](https://github.com/NixOS/nix/pull/10973) [#11034](https://github.com/NixOS/nix/pull/11034) [#11054](https://github.com/NixOS/nix/pull/11054) [#11055](https://github.com/NixOS/nix/pull/11055) [#11060](https://github.com/NixOS/nix/pull/11060) [#11064](https://github.com/NixOS/nix/pull/11064) [#11155](https://github.com/NixOS/nix/pull/11155)
+
+  These changes aim to replace the use of autotools and `make` with Meson for building various components of Nix. Additionally, each library is built in its own derivation, leveraging Meson's "subprojects" feature to allow a single development shell for building all libraries while also supporting separate builds. This approach aims to improve productivity and build modularity, compared to both make and a monolithic Meson-based derivation.
+
+  Special thanks to everyone who has contributed to the Meson port, particularly [**@p01arst0rm**](https://github.com/p01arst0rm) and [**@Qyriad**](https://github.com/Qyriad).
+
+  Authors: [**John Ericson (@Ericson2314)**](https://github.com/Ericson2314), [**Tom Bereknyei**](https://github.com/tomberek), [**Théophane Hufschmitt (@thufschmitt)**](https://github.com/thufschmitt), [**Valentin Gagarin (@fricklerhandwerk)**](https://github.com/fricklerhandwerk), [**Robert Hensing (@roberth)**](https://github.com/roberth)
+  Co-authors: [**@p01arst0rm**](https://github.com/p01arst0rm), [**@Qyriad**](https://github.com/Qyriad)
+
+- Evaluation cache: fix cache regressions [#10570](https://github.com/NixOS/nix/issues/10570) [#11086](https://github.com/NixOS/nix/pull/11086)
+
+  This update addresses two bugs in the evaluation cache system:
+
+  1. Regression in #10570: The evaluation cache was not being persisted in `nix develop`.
+  2. Nix could sometimes try to commit the evaluation cache SQLite transaction without there being an active transaction, resulting in non-error errors being printed.
+
+  Author: [**Lexi Mattick (@kognise)**](https://github.com/kognise)
+
+- Introduce `libnixflake` [#9063](https://github.com/NixOS/nix/pull/9063)
+
+  A new library, `libnixflake`, has been introduced to better separate the Flakes layer within Nix. This change refactors the codebase to encapsulate Flakes-specific functionality within its own library.
+
+  See the commits in the pull request for detailed changes, with the only significant code modifications happening in the initial commit.
+
+  This change was alluded to in [RFC 134](https://github.com/nixos/rfcs/blob/master/rfcs/0134-nix-store-layer.md) and is a step towards a more modular and maintainable codebase.
+
+  Author: [**John Ericson (@Ericson2314)**](https://github.com/Ericson2314)
+
+- CLI options `--arg-from-file` and `--arg-from-stdin` [#9913](https://github.com/NixOS/nix/pull/9913)
+
+- The `--debugger` now prints source location information, instead of the
+  pointers of source location information. Before:
+
+  ```
+  nix-repl> :bt
+  0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
+  0x600001522598
+  ```
+
+  After:
+
+  ```
+  0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
+  /nix/store/hg65h51xnp74ikahns9hyf3py5mlbbqq-source/overrides/default.nix:132:27
+
+     131|
+     132|       bootstrappingBase = pkgs.${self.python.pythonAttr}.pythonForBuild.pkgs;
+        |                           ^
+     133|     in
+  ```
+
+- Stop vendoring `toml11`
+
+  We don't apply any patches to it, and vendoring it locks users into
+  bugs (it hasn't been updated since its introduction in late 2021).
+
+  Author: [**Winter (@winterqt)**](https://github.com/winterqt)
+
+- Rename hash format `base32` to `nix32` [#8678](https://github.com/NixOS/nix/pull/8678)
+
+  Hash format `base32` was renamed to `nix32` since it used a special nix-specific character set for
+  [Base32](https://en.wikipedia.org/wiki/Base32).
+
+  **Deprecation**: Use `nix32` instead of `base32` as `toHashFormat`
+
+  For the builtin `convertHash`, the `toHashFormat` parameter now accepts the same hash formats as the `--to`/`--from`
+  parameters of the `nix hash conert` command: `"base16"`, `"nix32"`, `"base64"`, and `"sri"`. The former `"base32"` value
+  remains as a deprecated alias for `"nix32"`. Please convert your code from:
+
+  ```nix
+  builtins.convertHash { inherit hash hashAlgo; toHashFormat = "base32";}
+  ```
+
+  to
+
+  ```nix
+  builtins.convertHash { inherit hash hashAlgo; toHashFormat = "nix32";}
+  ```
+
+- Add `pipe-operators` experimental feature [#11131](https://github.com/NixOS/nix/pull/11131)
+
+  This is a draft implementation of [RFC 0148](https://github.com/NixOS/rfcs/pull/148).
+
+  The `pipe-operators` experimental feature adds [`<|` and `|>` operators][pipe operators] to the Nix language.
+  *a* `|>` *b* is equivalent to the function application *b* *a*, and
+  *a* `<|` *b* is equivalent to the function application *a* *b*.
+
+  For example:
+
+  ```
+  nix-repl> 1 |> builtins.add 2 |> builtins.mul 3
+  9
+
+  nix-repl> builtins.add 1 <| builtins.mul 2 <| 3
+  7
+  ```
+
+  `<|` and `|>` are right and left associative, respectively, and have lower precedence than any other operator.
+  These properties may change in future releases.
+
+  See [the RFC](https://github.com/NixOS/rfcs/pull/148) for more examples and rationale.
+
+  [pipe operators]: @docroot@/language/operators.md#pipe-operators
+
+- `nix-shell` shebang uses relative path [#4232](https://github.com/NixOS/nix/issues/4232) [#5088](https://github.com/NixOS/nix/pull/5088) [#11058](https://github.com/NixOS/nix/pull/11058)
+
+  <!-- unfortunately no link target for the specific syntax -->
+  Relative [path](@docroot@/language/types.md#type-path) literals in `nix-shell` shebang scripts' options are now resolved relative to the [script's location](@docroot@/glossary.md?highlight=base%20directory#gloss-base-directory).
+  Previously they were resolved relative to the current working directory.
+
+  For example, consider the following script in `~/myproject/say-hi`:
+
+  ```shell
+  #!/usr/bin/env nix-shell
+  #!nix-shell --expr 'import ./shell.nix'
+  #!nix-shell --arg toolset './greeting-tools.nix'
+  #!nix-shell -i bash
+  hello
+  ```
+
+  Older versions of `nix-shell` would resolve `shell.nix` relative to the current working directory, such as the user's home directory in this example:
+
+  ```console
+  [hostname:~]$ ./myproject/say-hi
+  error:
+         … while calling the 'import' builtin
+           at «string»:1:2:
+              1| (import ./shell.nix)
+               |  ^
+
+         error: path '/home/user/shell.nix' does not exist
+  ```
+
+  Since this release, `nix-shell` resolves `shell.nix` relative to the script's location, and `~/myproject/shell.nix` is used.
+
+  ```console
+  $ ./myproject/say-hi
+  Hello, world!
+  ```
+
+  **Opt-out**
+
+  This is technically a breaking change, so we have added an option so you can adapt independently of your Nix update.
+  The old behavior can be opted into by setting the option [`nix-shell-shebang-arguments-relative-to-script`](@docroot@/command-ref/conf-file.md#conf-nix-shell-shebang-arguments-relative-to-script) to `false`.
+  This option will be removed in a future release.
+
+  Author: [**Robert Hensing (@roberth)**](https://github.com/roberth)
+
+- Improve handling of tarballs that don't consist of a single top-level directory [#11195](https://github.com/NixOS/nix/pull/11195)
+
+  In previous Nix releases, the tarball fetcher (used by `builtins.fetchTarball`) erroneously merged top-level directories into a single directory, and silently discarded top-level files that are not directories. This is no longer the case. The new behaviour is that *only* if the tarball consists of a single directory, the top-level path component of the files in the tarball is removed (similar to `tar`'s `--strip-components=1`).
+
+  Author: [**Eelco Dolstra (@edolstra)**](https://github.com/edolstra)
+
+- Improve handling of tarballs that don't consist of a single top-level directory [#11195](https://github.com/NixOS/nix/pull/11195)
+
+  In previous Nix releases, the tarball fetcher (used by `builtins.fetchTarball`) erroneously merged top-level directories into a single directory, and silently discarded top-level files that are not directories. This is no longer the case.
+
+  Author: [**Eelco Dolstra (@edolstra)**](https://github.com/edolstra)
+
+- Setting to warn about large paths [#10778](https://github.com/NixOS/nix/pull/10778)
+
+  Nix can now warn when evaluation of a Nix expression causes a large
+  path to be copied to the Nix store. The threshold for this warning can
+  be configured using the `warn-large-path-threshold` setting,
+  e.g. `--warn-large-path-threshold 100M`.
+
+
+# Contributors
+
+This release was made possible by the following 43 contributors:
+
+- Andreas Rammhold [**(@andir)**](https://github.com/andir)
+- Andrew Marshall [**(@amarshall)**](https://github.com/amarshall)
+- Brian McKenna [**(@puffnfresh)**](https://github.com/puffnfresh)
+- Cameron [**(@SkamDart)**](https://github.com/SkamDart)
+- Cole Helbling [**(@cole-h)**](https://github.com/cole-h)
+- Corbin Simpson [**(@MostAwesomeDude)**](https://github.com/MostAwesomeDude)
+- Eelco Dolstra [**(@edolstra)**](https://github.com/edolstra)
+- Emily [**(@emilazy)**](https://github.com/emilazy)
+- Enno Richter [**(@elohmeier)**](https://github.com/elohmeier)
+- Farid Zakaria [**(@fzakaria)**](https://github.com/fzakaria)
+- HaeNoe [**(@haenoe)**](https://github.com/haenoe)
+- Hamir Mahal [**(@hamirmahal)**](https://github.com/hamirmahal)
+- Harmen [**(@alicebob)**](https://github.com/alicebob)
+- Ivan Trubach [**(@tie)**](https://github.com/tie)
+- Jared Baur [**(@jmbaur)**](https://github.com/jmbaur)
+- John Ericson [**(@Ericson2314)**](https://github.com/Ericson2314)
+- Jonathan De Troye [**(@detroyejr)**](https://github.com/detroyejr)
+- Jörg Thalheim [**(@Mic92)**](https://github.com/Mic92)
+- Klemens Nanni [**(@klemensn)**](https://github.com/klemensn)
+- Las Safin [**(@L-as)**](https://github.com/L-as)
+- Lexi Mattick [**(@kognise)**](https://github.com/kognise)
+- Matthew Bauer [**(@matthewbauer)**](https://github.com/matthewbauer)
+- Max “Goldstein” Siling [**(@GoldsteinE)**](https://github.com/GoldsteinE)
+- Mingye Wang [**(@Artoria2e5)**](https://github.com/Artoria2e5)
+- Philip Taron [**(@philiptaron)**](https://github.com/philiptaron)
+- Pierre Bourdon [**(@delroth)**](https://github.com/delroth)
+- Pino Toscano [**(@pinotree)**](https://github.com/pinotree)
+- RTUnreal [**(@RTUnreal)**](https://github.com/RTUnreal)
+- Robert Hensing [**(@roberth)**](https://github.com/roberth)
+- Romain Neil [**(@romain-neil)**](https://github.com/romain-neil)
+- Ryan Hendrickson [**(@rhendric)**](https://github.com/rhendric)
+- Sergei Trofimovich [**(@trofi)**](https://github.com/trofi)
+- Shogo Takata [**(@pineapplehunter)**](https://github.com/pineapplehunter)
+- Siddhant Kumar [**(@siddhantk232)**](https://github.com/siddhantk232)
+- Silvan Mosberger [**(@infinisil)**](https://github.com/infinisil)
+- Théophane Hufschmitt [**(@thufschmitt)**](https://github.com/thufschmitt)
+- Valentin Gagarin [**(@fricklerhandwerk)**](https://github.com/fricklerhandwerk)
+- Winter [**(@winterqt)**](https://github.com/winterqt)
+- jade [**(@lf-)**](https://github.com/lf-)
+- kirillrdy [**(@kirillrdy)**](https://github.com/kirillrdy)
+- pennae [**(@pennae)**](https://github.com/pennae)
+- poweredbypie [**(@poweredbypie)**](https://github.com/poweredbypie)
+- tomberek [**(@tomberek)**](https://github.com/tomberek)

doc/manual/src/release-notes/rl-2.4.md

@@ -23,7 +23,7 @@ more than 2800 commits from 195 contributors since release 2.3.
 * The **`nix` command** has seen a lot of work and is now almost at
   feature parity with the old command-line interface (the `nix-*`
   commands). It aims to be [more modern, consistent and pleasant to
-  use](../contributing/cli-guideline.md) than the old CLI. It is still
+  use](../development/cli-guideline.md) than the old CLI. It is still
   marked as experimental but its interface should not change much
   anymore in future releases.
 

doc/manual/src/store/file-system-object/content-address.md

@@ -82,4 +82,4 @@ In the future, we may support a Git-like hash for such file system objects, or w
 
 [file system object]: ../file-system-object.md
 [store object]: ../store-object.md
-[xp-feature-git-hashing]: @docroot@/contributing/experimental-features.md#xp-feature-git-hashing
+[xp-feature-git-hashing]: @docroot@/development/experimental-features.md#xp-feature-git-hashing

doc/manual/src/store/store-object/content-address.md

@@ -92,4 +92,4 @@ becomes more widespread, this restriction will be revisited.
 
 [fso-ca]: ../file-system-object/content-address.md
 [sp-spec]: @docroot@/protocols/store-path.md
-[xp-feature-git-hashing]: @docroot@/contributing/experimental-features.md#xp-feature-git-hashing
+[xp-feature-git-hashing]: @docroot@/development/experimental-features.md#xp-feature-git-hashing

flake.lock

@@ -3,11 +3,11 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1673956053,
+        "lastModified": 1696426674,
-        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
+        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
         "owner": "edolstra",
         "repo": "flake-compat",
-        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
         "type": "github"
       },
       "original": {
@@ -23,11 +23,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1712014858,
+        "lastModified": 1719994518,
-        "narHash": "sha256-sB4SWl2lX95bExY2gMFG5HIzvva5AVMJd4Igm+GpZNw=",
+        "narHash": "sha256-pQMhCCHyQGRzdfAkdJ4cIWiw+JNuWsTX7f0ZYSyz0VY=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "9126214d0a59633752a136528f5f3b9aa8565b7d",
+        "rev": "9227223f6d922fee3c7b190b2cc238a99527bbb7",
         "type": "github"
       },
       "original": {
@@ -51,49 +51,60 @@
         "type": "github"
       }
     },
-    "flake-utils": {
+    "git-hooks-nix": {
+      "inputs": {
+        "flake-compat": [],
+        "gitignore": [],
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "nixpkgs-stable": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1667395993,
+        "lastModified": 1721042469,
-        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "narHash": "sha256-6FPUl7HVtvRHCCBQne7Ylp4p+dpP3P/OYuzjztZ4s70=",
-        "owner": "numtide",
+        "owner": "cachix",
-        "repo": "flake-utils",
+        "repo": "git-hooks.nix",
-        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "rev": "f451c19376071a90d8c58ab1a953c6e9840527fd",
         "type": "github"
       },
       "original": {
-        "owner": "numtide",
+        "owner": "cachix",
-        "repo": "flake-utils",
+        "repo": "git-hooks.nix",
         "type": "github"
       }
     },
     "libgit2": {
       "flake": false,
       "locked": {
-        "lastModified": 1697646580,
+        "lastModified": 1715853528,
-        "narHash": "sha256-oX4Z3S9WtJlwvj0uH9HlYcWv+x1hqp8mhXl7HsLu2f0=",
+        "narHash": "sha256-J2rCxTecyLbbDdsyBWn9w7r3pbKRMkI9E7RvRgAqBdY=",
         "owner": "libgit2",
         "repo": "libgit2",
-        "rev": "45fd9ed7ae1a9b74b957ef4f337bc3c8b3df01b5",
+        "rev": "36f7e21ad757a3dacc58cf7944329da6bc1d6e96",
         "type": "github"
       },
       "original": {
         "owner": "libgit2",
+        "ref": "v1.8.1",
         "repo": "libgit2",
         "type": "github"
       }
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1717432640,
+        "lastModified": 1721548954,
-        "narHash": "sha256-+f9c4/ZX5MWDOuB1rKoWj+lBNm0z0rs4CK47HBLxy1o=",
+        "narHash": "sha256-7cCC8+Tdq1+3OPyc3+gVo9dzUNkNIQfwSDJ2HSi2u3o=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "88269ab3044128b7c2f4c7d68448b2fb50456870",
+        "rev": "63d37ccd2d178d54e7fb691d7ec76000740ea24a",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "release-24.05",
+        "ref": "nixos-24.05",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -130,42 +141,16 @@
         "type": "github"
       }
     },
-    "pre-commit-hooks": {
-      "inputs": {
-        "flake-compat": [],
-        "flake-utils": "flake-utils",
-        "gitignore": [],
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "nixpkgs-stable": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1712897695,
-        "narHash": "sha256-nMirxrGteNAl9sWiOhoN5tIHyjBbVi5e2tgZUgZlK3Y=",
-        "owner": "cachix",
-        "repo": "pre-commit-hooks.nix",
-        "rev": "40e6053ecb65fcbf12863338a6dcefb3f55f1bf8",
-        "type": "github"
-      },
-      "original": {
-        "owner": "cachix",
-        "repo": "pre-commit-hooks.nix",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "flake-compat": "flake-compat",
         "flake-parts": "flake-parts",
         "flake-schemas": "flake-schemas",
+        "git-hooks-nix": "git-hooks-nix",
         "libgit2": "libgit2",
         "nixpkgs": "nixpkgs",
         "nixpkgs-23-11": "nixpkgs-23-11",
-        "nixpkgs-regression": "nixpkgs-regression",
+        "nixpkgs-regression": "nixpkgs-regression"
-        "pre-commit-hooks": "pre-commit-hooks"
       }
     }
   },

flake.nix

@@ -1,32 +1,30 @@
 {
   description = "The purely functional package manager";
 
-  # TODO switch to nixos-23.11-small
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
-  #      https://nixpk.gs/pr-tracker.html?pr=291954
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-24.05";
   inputs.nixpkgs-regression.url = "github:NixOS/nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2";
   inputs.nixpkgs-23-11.url = "github:NixOS/nixpkgs/a62e6edd6d5e1fa0329b8653c801147986f8d446";
   inputs.flake-compat = { url = "github:edolstra/flake-compat"; flake = false; };
-  inputs.libgit2 = { url = "github:libgit2/libgit2"; flake = false; };
+  inputs.libgit2 = { url = "github:libgit2/libgit2/v1.8.1"; flake = false; };
   inputs.flake-schemas.url = "github:DeterminateSystems/flake-schemas";
 
   # dev tooling
   inputs.flake-parts.url = "github:hercules-ci/flake-parts";
-  inputs.pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
+  inputs.git-hooks-nix.url = "github:cachix/git-hooks.nix";
   # work around https://github.com/NixOS/nix/issues/7730
   inputs.flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
-  inputs.pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
+  inputs.git-hooks-nix.inputs.nixpkgs.follows = "nixpkgs";
-  inputs.pre-commit-hooks.inputs.nixpkgs-stable.follows = "nixpkgs";
+  inputs.git-hooks-nix.inputs.nixpkgs-stable.follows = "nixpkgs";
   # work around 7730 and https://github.com/NixOS/nix/issues/7807
-  inputs.pre-commit-hooks.inputs.flake-compat.follows = "";
+  inputs.git-hooks-nix.inputs.flake-compat.follows = "";
-  inputs.pre-commit-hooks.inputs.gitignore.follows = "";
+  inputs.git-hooks-nix.inputs.gitignore.follows = "";
 
   outputs = inputs@{ self, nixpkgs, nixpkgs-regression, libgit2, flake-schemas, ... }:
 
     let
       inherit (nixpkgs) lib;
 
-      officialRelease = false;
+      officialRelease = true;
 
       version = lib.fileContents ./.version + versionSuffix;
       versionSuffix =
@@ -145,6 +143,7 @@
 
           nix_noTests = final.nix.override {
             doInstallCheck = false;
+            doCheck = false;
           };
 
           # See https://github.com/NixOS/nixpkgs/pull/214409
@@ -280,6 +279,7 @@
             in
               "-D${prefix}:${rest}";
           havePerl = stdenv.buildPlatform == stdenv.hostPlatform && stdenv.hostPlatform.isUnix;
+          ignoreCrossFile = flags: builtins.filter (flag: !(lib.strings.hasInfix "cross-file" flag)) flags;
         in {
           pname = "shell-for-" + attrs.pname;
 
@@ -311,10 +311,12 @@
           };
 
           mesonFlags =
-            map (transformFlag "libutil") pkgs.nixComponents.nix-util.mesonFlags
+            map (transformFlag "libutil") (ignoreCrossFile pkgs.nixComponents.nix-util.mesonFlags)
-            ++ map (transformFlag "libstore") pkgs.nixComponents.nix-store.mesonFlags
+            ++ map (transformFlag "libstore") (ignoreCrossFile pkgs.nixComponents.nix-store.mesonFlags)
-            ++ map (transformFlag "libfetchers") pkgs.nixComponents.nix-fetchers.mesonFlags
+            ++ map (transformFlag "libfetchers") (ignoreCrossFile pkgs.nixComponents.nix-fetchers.mesonFlags)
-            ++ lib.optionals havePerl (map (transformFlag "perl") pkgs.nixComponents.nix-perl-bindings.mesonFlags)
+            ++ lib.optionals havePerl (map (transformFlag "perl") (ignoreCrossFile pkgs.nixComponents.nix-perl-bindings.mesonFlags))
+            ++ map (transformFlag "libexpr") (ignoreCrossFile pkgs.nixComponents.nix-expr.mesonFlags)
+            ++ map (transformFlag "libcmd") (ignoreCrossFile pkgs.nixComponents.nix-cmd.mesonFlags)
             ;
 
           nativeBuildInputs = attrs.nativeBuildInputs or []
@@ -324,8 +326,17 @@
             ++ lib.optionals havePerl pkgs.nixComponents.nix-perl-bindings.nativeBuildInputs
             ++ pkgs.nixComponents.nix-internal-api-docs.nativeBuildInputs
             ++ pkgs.nixComponents.nix-external-api-docs.nativeBuildInputs
+            ++ lib.optional
+              (!stdenv.buildPlatform.canExecute stdenv.hostPlatform
+                 # Hack around https://github.com/nixos/nixpkgs/commit/bf7ad8cfbfa102a90463433e2c5027573b462479
+                 && !(stdenv.hostPlatform.isWindows && stdenv.buildPlatform.isDarwin)
+                 && stdenv.hostPlatform.emulatorAvailable pkgs.buildPackages
+                 && lib.meta.availableOn stdenv.buildPlatform (stdenv.hostPlatform.emulator pkgs.buildPackages))
+              pkgs.buildPackages.mesonEmulatorHook
             ++ [
               pkgs.buildPackages.cmake
+              pkgs.buildPackages.shellcheck
+              pkgs.buildPackages.changelog-d
               modular.pre-commit.settings.package
               (pkgs.writeScriptBin "pre-commit-hooks-install"
                 modular.pre-commit.settings.installationScript)

maintainers/README.md

@@ -50,7 +50,7 @@ The team meets twice a week (times are denoted in the [Europe/Amsterdam](https:/
        - mark it as draft if it is blocked on the contributor
        - escalate it back to the team by moving it to To discuss, and leaving a comment as to why the issue needs to be discussed again.
 
-- Work meeting: [Mondays 13:00-15:00 Europe/Amsterdam](https://www.google.com/calendar/event?eid=Ym52NDdzYnRic2NzcDcybjZiNDhpNzhpa3NfMjAyNDA1MTNUMTIwMDAwWiBiOW81MmZvYnFqYWs4b3E4bGZraGczdDBxZ0Bn)
+- Work meeting: [Mondays 14:00-16:00 Europe/Amsterdam](https://www.google.com/calendar/event?eid=Ym52NDdzYnRic2NzcDcybjZiNDhpNzhpa3NfMjAyNDA1MTNUMTIwMDAwWiBiOW81MmZvYnFqYWs4b3E4bGZraGczdDBxZ0Bn)
 
   1. Code review on pull requests from [In review](#in-review).
   2. Other chores and tasks.

maintainers/data/release-credits-email-to-handle.json

@@ -0,0 +1,52 @@
+{
+    "bogus": "bogus",
+    "edolstra@gmail.com": "edolstra",
+    "roberth@users.noreply.github.com": "roberth",
+    "toscano.pino@tiscali.it": "pinotree",
+    "valentin@gagarin.work": "fricklerhandwerk",
+    "mr.trubach@icloud.com": "tie",
+    "robert@roberthensing.nl": "roberth",
+    "lix@jade.fyi": "lf-",
+    "cole.e.helbling@outlook.com": "cole-h",
+    "joerg@thalheim.io": "Mic92",
+    "John.Ericson@Obsidian.Systems": "Ericson2314",
+    "ryan.hendrickson@alum.mit.edu": "rhendric",
+    "67135060+poweredbypie@users.noreply.github.com": "poweredbypie",
+    "detroyejr@outlook.com": "detroyejr",
+    "silvan.mosberger@tweag.io": "infinisil",
+    "vcs@emily.moe": "emilazy",
+    "farid.m.zakaria@gmail.com": "fzakaria",
+    "22859658+RTUnreal@users.noreply.github.com": "RTUnreal",
+    "me@las.rs": "L-as",
+    "philip.taron@gmail.com": "philiptaron",
+    "root@goldstein.rs": "GoldsteinE",
+    "tomberek@users.noreply.github.com": "tomberek",
+    "lexi.mattick@neuralink.com": "kognise",
+    "andrew@johnandrewmarshall.com": "amarshall",
+    "contact@romain-neil.fr": "romain-neil",
+    "Mic92@users.noreply.github.com": "Mic92",
+    "valentin.gagarin@tweag.io": "fricklerhandwerk",
+    "siddhantk232@gmail.com": "siddhantk232",
+    "kn@openbsd.org": "klemensn",
+    "slyich@gmail.com": "trofi",
+    "theophane.hufschmitt@tweag.io": "thufschmitt",
+    "alicebob@lijzij.de": "alicebob",
+    "winter@winter.cafe": "winterqt",
+    "brian@brianmckenna.org": "puffnfresh",
+    "git@haenoe.party": "haenoe",
+    "peshogo@gmail.com": "pineapplehunter",
+    "poweredbypie@users.noreply.github.com": "poweredbypie",
+    "arthur200126@gmail.com": "Artoria2e5",
+    "tomberek@gmail.com": "tomberek",
+    "jaredbaur@fastmail.com": "jmbaur",
+    "andreas@rammhold.de": "andir",
+    "hamirmahal@gmail.com": "hamirmahal",
+    "git@JohnEricson.me": "Ericson2314",
+    "8763518+SkamDart@users.noreply.github.com": "SkamDart",
+    "kirillrdy@gmail.com": "kirillrdy",
+    "pennae@lix.systems": "pennae",
+    "delroth@gmail.com": "delroth",
+    "enno@nerdworks.de": "elohmeier",
+    "mjbauer95@gmail.com": "matthewbauer",
+    "MostAwesomeDude@gmail.com": "MostAwesomeDude"
+}

maintainers/data/release-credits-handle-to-name.json

@@ -0,0 +1,45 @@
+{
+    "fzakaria": "Farid Zakaria",
+    "kognise": "Lexi Mattick",
+    "L-as": "Las Safin",
+    "haenoe": "HaeNoe",
+    "andir": "Andreas Rammhold",
+    "matthewbauer": "Matthew Bauer",
+    "emilazy": "Emily",
+    "pineapplehunter": "Shogo Takata",
+    "RTUnreal": null,
+    "jmbaur": "Jared Baur",
+    "Ericson2314": "John Ericson",
+    "pinotree": "Pino Toscano",
+    "tie": "Ivan Trubach",
+    "poweredbypie": null,
+    "fricklerhandwerk": "Valentin Gagarin",
+    "Mic92": "J\u00f6rg Thalheim",
+    "alicebob": "Harmen",
+    "elohmeier": "Enno Richter",
+    "delroth": "Pierre Bourdon",
+    "kirillrdy": null,
+    "thufschmitt": "Th\u00e9ophane Hufschmitt",
+    "detroyejr": "Jonathan De Troye",
+    "klemensn": "Klemens Nanni",
+    "tomberek": null,
+    "rhendric": "Ryan Hendrickson",
+    "philiptaron": "Philip Taron",
+    "puffnfresh": "Brian McKenna",
+    "lf-": "jade",
+    "romain-neil": "Romain Neil",
+    "hamirmahal": "Hamir Mahal",
+    "edolstra": "Eelco Dolstra",
+    "Artoria2e5": "Mingye Wang",
+    "SkamDart": "Cameron",
+    "roberth": "Robert Hensing",
+    "amarshall": "Andrew Marshall",
+    "trofi": "Sergei Trofimovich",
+    "cole-h": "Cole Helbling",
+    "infinisil": "Silvan Mosberger",
+    "siddhantk232": "Siddhant Kumar",
+    "winterqt": "Winter",
+    "GoldsteinE": "Max \u201cGoldstein\u201d Siling",
+    "pennae": null,
+    "MostAwesomeDude": "Corbin Simpson"
+}

maintainers/flake-module.nix

@@ -2,7 +2,7 @@
 
 {
   imports = [
-    inputs.pre-commit-hooks.flakeModule
+    inputs.git-hooks-nix.flakeModule
   ];
 
   perSystem = { config, pkgs, ... }: {
@@ -495,7 +495,6 @@
           excludes = [
             # We haven't linted these files yet
             ''^config/install-sh$''
-            ''^misc/systemv/nix-daemon$''
             ''^misc/bash/completion\.sh$''
             ''^misc/fish/completion\.fish$''
             ''^misc/zsh/completion\.zsh$''

maintainers/release-credits

@@ -0,0 +1,184 @@
+#!/usr/bin/env nix
+# vim: set filetype=python:
+#!nix develop --impure --expr
+#!nix ``
+#!nix   let flake = builtins.getFlake ("git+file://" + toString ../.);
+#!nix       pkgs = flake.inputs.nixpkgs.legacyPackages.${builtins.currentSystem};
+#!nix   in pkgs.mkShell { nativeBuildInputs = [ 
+#!nix        (pkgs.python3.withPackages (ps: with ps; [ requests ]))
+#!nix   ]; }
+#!nix `` --command python3
+
+# This script lists out the contributors for a given release.
+# It must be run from the root of the Nix repository.
+
+import os
+import sys
+import json
+import requests
+
+github_token = os.environ.get("GITHUB_TOKEN")
+if not github_token:
+    print("GITHUB_TOKEN is not set. If you hit the rate limit, set it", file=sys.stderr)
+    # Might be ok, as we have a cache.
+    # raise ValueError("GITHUB_TOKEN must be set")
+
+# 1. Read the current version in .version
+version = os.environ.get("VERSION")
+if not version:
+    version = open(".version").read().strip()
+
+print(f"Generating release credits for Nix {version}", file=sys.stderr)
+
+# 2. Compute previous version
+vcomponents = version.split(".")
+if len(vcomponents) >= 2:
+    prev_version = f"{vcomponents[0]}.{int(vcomponents[1])-1}.0"
+else:
+    raise ValueError(".version must have at least two components")
+
+# For unreleased versions
+endref = "HEAD"
+# For older releases
+# endref = version
+
+# 2. Find the merge base between the current version and the previous version
+mergeBase = os.popen(f"git merge-base {prev_version} {endref}").read().strip()
+print(f"Merge base between {prev_version} and {endref} is {mergeBase}", file=sys.stderr)
+
+# 3. Find the date of the merge base
+mergeBaseDate = os.popen(f"git show -s --format=%ci {mergeBase}").read().strip()[0:10]
+print(f"Merge base date is {mergeBaseDate}", file=sys.stderr)
+
+# 4. Get the commits between the merge base and the current version
+
+def get_commits():
+    raw = os.popen(f"git log --pretty=format:'%H\t%an\t%ae' {mergeBase}..{endref}").read().strip()
+    lines = raw.split("\n")
+    return [ { "hash": items[0], "author": items[1], "email": items[2] }
+        for line in lines
+        for items in (line.split("\t"),)
+    ]
+
+def commits_to_first_commit_by_email(commits):
+    by_email = dict()
+    for commit in commits:
+        email = commit["email"]
+        if email not in by_email:
+            by_email[email] = commit
+    return by_email
+
+
+samples = commits_to_first_commit_by_email(get_commits())
+
+# For quick testing, only pick two samples from the dict
+# samples = dict(list(samples.items())[:2])
+
+# Query the GitHub API to get handle
+def get_github_commit(commit):
+    url = f"https://api.github.com/repos/NixOS/nix/commits/{commit['hash']}"
+    headers = {'Authorization': f'token {github_token}'}
+    response = requests.get(url, headers=headers)
+    response.raise_for_status()
+    return response.json()
+
+class Cache:
+    def __init__(self, filename, require = True):
+        self.filename = filename
+        try:
+            with open(filename, "r") as f:
+                self.values = json.load(f)
+        except FileNotFoundError:
+            if require:
+                raise
+            self.values = dict()
+    def save(self):
+        with open(self.filename, "w") as f:
+            json.dump(self.values, f, indent=4)
+        print(f"Saved cache to {self.filename}", file=sys.stderr)
+
+# The email to handle cache maps email addresses to either
+#  - a handle (string)
+#  - None (if no handle was found)
+email_to_handle_cache = Cache("maintainers/data/release-credits-email-to-handle.json")
+
+handles = set()
+emails = dict()
+
+for sample in samples:
+    s = samples[sample]
+    email = s["email"]
+    if not email in email_to_handle_cache.values:
+        print(f"Querying GitHub API for {s['hash']}, to get handle for {s['email']}")
+        ghc = get_github_commit(samples[sample])
+        gha = ghc["author"]
+        if gha and gha["login"]:
+            handle = gha["login"]
+            print(f"Handle: {handle}")
+            email_to_handle_cache.values[email] = handle
+        else:
+            print(f"Found no handle for {s['email']}")
+            email_to_handle_cache.values[email] = None
+    handle = email_to_handle_cache.values[email]
+    if handle is not None:
+        handles.add(handle)
+    else:
+        emails[email] = s["author"]
+
+# print(email_to_handle_cache.values)
+
+email_to_handle_cache.save()
+
+handle_to_name_cache = Cache("maintainers/data/release-credits-handle-to-name.json")
+
+print(f"Found {len(handles)} handles", file=sys.stderr)
+
+for handle in handles:
+    if not handle in handle_to_name_cache.values:
+        print(f"Querying GitHub API for {handle}, to get name", file=sys.stderr)
+        url = f"https://api.github.com/users/{handle}"
+        headers = {'Authorization': f'token {github_token}'}
+        response = requests.get(url, headers=headers)
+        response.raise_for_status()
+        user = response.json()
+        name = user["name"]
+        print(f"Name: {name}", file=sys.stderr)
+        handle_to_name_cache.values[handle] = name
+
+handle_to_name_cache.save()
+
+entries = list()
+
+def is_bot(handle):
+    return handle.endswith("[bot]")
+
+for handle in handles:
+    name = handle_to_name_cache.values[handle]
+    if name is None:
+        # This way it looks more regular
+        name = handle
+
+    # Note to bots: I'm only doing this because it would distract humans, and
+    # therefore delay your creation. I'm sorry; it's for your benefit.
+    if not is_bot(handle):
+        entries += [ f"- {name} [**(@{handle})**](https://github.com/{handle})" ]
+
+def shuffle(entries):
+    salt = os.urandom(16)
+    return sorted(entries, key=lambda x: hash((x, salt)))
+
+# Fair ordering is undecidable
+entries = shuffle(entries)
+
+# For a sanity check, we could sort the entries by handle instead.
+# entries = sorted(entries)
+
+print("")
+print(f"This release was made possible by the following {len(entries)} contributors:")
+print("")
+
+for entry in entries:
+    print(entry)
+
+for email in emails:
+    print(f"- {emails[email]}")

maintainers/release-notes

@@ -1,4 +1,5 @@
 #!/usr/bin/env nix
+# vim: set filetype=bash:
 #!nix shell .#changelog-d --command bash
 
 # --- CONFIGURATION ---
@@ -151,6 +152,13 @@ section_title="Release $version_full ($DATE)"
   echo "# $section_title"
   echo
   changelog-d doc/manual/rl-next | sed -e 's/ *$//'
+
+  if ! $IS_PATCH; then
+    echo
+    echo "# Contributors"
+    echo
+    VERSION=$version_full ./maintainers/release-credits
+  fi
 ) | tee -a $file
 
 log "Wrote $file"

maintainers/release-process.md

@@ -39,6 +39,10 @@ release:
 * Proof-read / edit / rearrange the release notes if needed. Breaking changes
   and highlights should go to the top.
 
+* Run `maintainers/release-credits` to make sure the credits script works
+  and produces a sensible output. Some emails might not automatically map to
+  a GitHub handle.
+
 * Push.
 
   ```console

meson.build

@@ -26,9 +26,12 @@ subproject('external-api-docs')
 subproject('libutil-c')
 subproject('libstore-c')
 subproject('libexpr-c')
+subproject('libmain-c')
 
 # Language Bindings
-subproject('perl')
+if not meson.is_cross_build()
+  subproject('perl')
+endif
 
 # Testing
 subproject('nix-util-test-support')

misc/systemv/nix-daemon

@@ -34,6 +34,7 @@ else
 fi
 
 # Source function library.
+# shellcheck source=/dev/null
 . /etc/init.d/functions
 
 LOCKFILE=/var/lock/subsys/nix-daemon
@@ -41,14 +42,20 @@ RUNDIR=/var/run/nix
 PIDFILE=${RUNDIR}/nix-daemon.pid
 RETVAL=0
 
-base=${0##*/}
+# https://www.shellcheck.net/wiki/SC3004
+# Check if gettext exists
+if ! type gettext > /dev/null 2>&1
+then
+  # If not, create a dummy function that returns the input verbatim
+  gettext() { printf '%s' "$1"; }
+fi
 
 start() {
 
     mkdir -p ${RUNDIR}
     chown ${NIX_DAEMON_USER}:${NIX_DAEMON_USER} ${RUNDIR}
 
-    echo -n $"Starting nix daemon... "
+    printf '%s' "$(gettext 'Starting nix daemon... ')"
 
     daemonize -u $NIX_DAEMON_USER -p ${PIDFILE} $NIX_DAEMON_BIN $NIX_DAEMON_OPTS
     RETVAL=$?
@@ -58,7 +65,7 @@ start() {
 }
 
 stop() {
-    echo -n $"Shutting down nix daemon: "
+    printf '%s' "$(gettext 'Shutting down nix daemon: ')"
     killproc -p ${PIDFILE} $NIX_DAEMON_BIN
     RETVAL=$?
     [ $RETVAL -eq 0 ] && rm -f ${LOCKFILE} ${PIDFILE}
@@ -67,7 +74,7 @@ stop() {
 }
 
 reload() {
-    echo -n $"Reloading nix daemon... "
+    printf '%s' "$(gettext 'Reloading nix daemon... ')"
     killproc -p ${PIDFILE} $NIX_DAEMON_BIN -HUP
     RETVAL=$?
     echo
@@ -105,7 +112,7 @@ case "$1" in
         fi
     ;;
   *)
-        echo $"Usage: $0 {start|stop|status|restart|condrestart}"
+        printf '%s' "$(gettext "Usage: $0 {start|stop|status|restart|condrestart}")"
         exit 2
     ;;
 esac

mk/platform.mk

@@ -29,4 +29,8 @@ ifdef HOST_OS
     HOST_SOLARIS = 1
     HOST_UNIX = 1
   endif
+  ifeq ($(HOST_KERNEL), gnu)
+    HOST_HURD = 1
+    HOST_UNIX = 1
+  endif
 endif

mk/run-test.sh

@@ -28,7 +28,7 @@ run_test
 
 if [[ "$status" = 0 ]]; then
   echo "$post_run_msg [${green}PASS$normal]"
-elif [[ "$status" = 99 ]]; then
+elif [[ "$status" = 77 ]]; then
   echo "$post_run_msg [${yellow}SKIP$normal]"
 else
   echo "$post_run_msg [${red}FAIL$normal]"

package.nix

@@ -218,7 +218,8 @@ in {
   ] ++ lib.optional stdenv.hostPlatform.isStatic unixtools.hexdump
   ;
 
-  buildInputs = lib.optionals doBuild [
+  buildInputs = lib.optionals doBuild (
+  [
     brotli
     bzip2
     curl
@@ -239,16 +240,14 @@ in {
     ++ lib.optional stdenv.hostPlatform.isx86_64 libcpuid
     # There have been issues building these dependencies
     ++ lib.optional (stdenv.hostPlatform == stdenv.buildPlatform && (stdenv.isLinux || stdenv.isDarwin))
-      (aws-sdk-cpp.override {
+      aws-sdk-cpp
-        apis = ["s3" "transfer"];
+  );
-        customMemoryManagement = false;
-      })
-  ;
 
-  propagatedBuildInputs = [
+  propagatedBuildInputs = lib.optionals doBuild ([
     boost
     nlohmann_json
-  ] ++ lib.optional enableGC boehmgc;
+  ] ++ lib.optional enableGC boehmgc
+  );
 
   dontBuild = !attrs.doBuild;
   doCheck = attrs.doCheck;

packaging/components.nix

@@ -29,6 +29,7 @@ in
   nix-flake-tests = callPackage ../tests/unit/libflake/package.nix { };
 
   nix-main = callPackage ../src/libmain/package.nix { };
+  nix-main-c = callPackage ../src/libmain-c/package.nix { };
 
   nix-cmd = callPackage ../src/libcmd/package.nix { };
 

packaging/dependencies.nix

@@ -61,11 +61,33 @@ let
       workDir = null;
     };
 
+  # Work around weird `--as-needed` linker behavior with BSD, see
+  # https://github.com/mesonbuild/meson/issues/3593
+  bsdNoLinkAsNeeded = finalAttrs: prevAttrs:
+    lib.optionalAttrs stdenv.hostPlatform.isBSD {
+      mesonFlags = [ (lib.mesonBool "b_asneeded" false) ] ++ prevAttrs.mesonFlags or [];
+    };
+
+  miscGoodPractice = finalAttrs: prevAttrs:
+    {
+      strictDeps = prevAttrs.strictDeps or true;
+      enableParallelBuilding = true;
+    };
+
 in
 scope: {
   inherit stdenv versionSuffix;
   version = lib.fileContents ../.version + versionSuffix;
 
+  aws-sdk-cpp = (pkgs.aws-sdk-cpp.override {
+    apis = [ "s3" "transfer" ];
+    customMemoryManagement = false;
+  }).overrideAttrs {
+    # only a stripped down version is built, which takes a lot less resources
+    # to build, so we don't need a "big-parallel" machine.
+    requiredSystemFeatures = [ ];
+  };
+
   libseccomp = pkgs.libseccomp.overrideAttrs (_: rec {
     version = "2.5.5";
     src = pkgs.fetchurl {
@@ -130,7 +152,16 @@ scope: {
 
   inherit resolvePath filesetToSource;
 
-  mkMesonDerivation = f: stdenv.mkDerivation (lib.extends localSourceLayer f);
+  mkMesonDerivation = f: let
+    exts = [
+      miscGoodPractice
+      bsdNoLinkAsNeeded
+      localSourceLayer
+    ];
+  in stdenv.mkDerivation
+   (lib.extends
+     (lib.foldr lib.composeExtensions (_: _: {}) exts)
+     f);
 
   inherit (inputs) flake-schemas;
 }

packaging/hydra.nix

@@ -54,6 +54,7 @@ let
     "nix-flake"
     "nix-flake-tests"
     "nix-main"
+    "nix-main-c"
     "nix-cmd"
     "nix-ng"
   ];

src/build-remote/build-remote.cc

@@ -11,6 +11,7 @@
 
 #include "machines.hh"
 #include "shared.hh"
+#include "plugin.hh"
 #include "pathlocks.hh"
 #include "globals.hh"
 #include "serialise.hh"
@@ -100,7 +101,7 @@ static int main_build_remote(int argc, char * * argv)
         }
 
         std::optional<StorePath> drvPath;
-        StoreReference storeUri;
+        std::string storeUri;
 
         while (true) {
 
@@ -233,17 +234,16 @@ static int main_build_remote(int argc, char * * argv)
                 lock = -1;
 
                 try {
+                    storeUri = bestMachine->storeUri.render();
 
-                    Activity act(*logger, lvlTalkative, actUnknown, fmt("connecting to '%s'", bestMachine->storeUri.render()));
+                    Activity act(*logger, lvlTalkative, actUnknown, fmt("connecting to '%s'", storeUri));
 
                     sshStore = bestMachine->openStore();
                     sshStore->connect();
-                    storeUri = bestMachine->storeUri;
-
                 } catch (std::exception & e) {
                     auto msg = chomp(drainFD(5, false));
                     printError("cannot build on '%s': %s%s",
-                        bestMachine->storeUri.render(), e.what(),
+                        storeUri, e.what(),
                         msg.empty() ? "" : ": " + msg);
                     bestMachine->enabled = false;
                     continue;
@@ -258,15 +258,28 @@ connected:
 
         assert(sshStore);
 
-        std::cerr << "# accept\n" << storeUri.render() << "\n";
+        std::cerr << "# accept\n" << storeUri << "\n";
 
         auto inputs = readStrings<PathSet>(source);
         auto wantedOutputs = readStrings<StringSet>(source);
 
-        AutoCloseFD uploadLock = openLockFile(currentLoad + "/" + escapeUri(storeUri.render()) + ".upload-lock", true);
+        AutoCloseFD uploadLock;
+        {
+            auto setUpdateLock = [&](auto && fileName){
+                uploadLock = openLockFile(currentLoad + "/" + escapeUri(fileName) + ".upload-lock", true);
+            };
+            try {
+                setUpdateLock(storeUri);
+            } catch (SysError & e) {
+                if (e.errNo != ENAMETOOLONG) throw;
+                // Try again hashing the store URL so we have a shorter path
+                auto h = hashString(HashAlgorithm::MD5, storeUri);
+                setUpdateLock(h.to_string(HashFormat::Base64, false));
+            }
+        }
 
         {
-            Activity act(*logger, lvlTalkative, actUnknown, fmt("waiting for the upload lock to '%s'", storeUri.render()));
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("waiting for the upload lock to '%s'", storeUri));
 
             auto old = signal(SIGALRM, handleAlarm);
             alarm(15 * 60);
@@ -279,7 +292,7 @@ connected:
         auto substitute = settings.buildersUseSubstitutes ? Substitute : NoSubstitute;
 
         {
-            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying dependencies to '%s'", storeUri.render()));
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying dependencies to '%s'", storeUri));
             copyPaths(*store, *sshStore, store->parseStorePathSet(inputs), NoRepair, NoCheckSigs, substitute);
         }
 
@@ -317,7 +330,7 @@ connected:
             optResult = sshStore->buildDerivation(*drvPath, (const BasicDerivation &) drv);
             auto & result = *optResult;
             if (!result.success())
-                throw Error("build of '%s' on '%s' failed: %s", store->printStorePath(*drvPath), storeUri.render(), result.errorMsg);
+                throw Error("build of '%s' on '%s' failed: %s", store->printStorePath(*drvPath), storeUri, result.errorMsg);
         } else {
             copyClosure(*store, *sshStore, StorePathSet {*drvPath}, NoRepair, NoCheckSigs, substitute);
             auto res = sshStore->buildPathsWithResults({
@@ -360,7 +373,7 @@ connected:
         }
 
         if (!missingPaths.empty()) {
-            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying outputs from '%s'", storeUri.render()));
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying outputs from '%s'", storeUri));
             if (auto localStore = store.dynamic_pointer_cast<LocalStore>())
                 for (auto & path : missingPaths)
                     localStore->locksHeld.insert(store->printStorePath(path)); /* FIXME: ugly */

src/external-api-docs/package.nix

@@ -53,10 +53,6 @@ mkMesonDerivation (finalAttrs: {
     echo "doc external-api-docs $out/share/doc/nix/external-api/html" >> ''${!outputDoc}/nix-support/hydra-build-products
   '';
 
-  enableParallelBuilding = true;
-
-  strictDeps = true;
-
   meta = {
     platforms = lib.platforms.all;
   };

src/internal-api-docs/package.nix

@@ -48,10 +48,6 @@ mkMesonDerivation (finalAttrs: {
     echo "doc internal-api-docs $out/share/doc/nix/internal-api/html" >> ''${!outputDoc}/nix-support/hydra-build-products
   '';
 
-  enableParallelBuilding = true;
-
-  strictDeps = true;
-
   meta = {
     platforms = lib.platforms.all;
   };

src/libcmd/common-eval-args.cc

@@ -90,75 +90,11 @@ MixEvalArgs::MixEvalArgs()
         .longName = "include",
         .shortName = 'I',
         .description = R"(
-  Add *path* to the Nix search path. The Nix search path is
+  Add *path* to search path entries used to resolve [lookup paths](@docroot@/language/constructs/lookup-path.md)
-  initialized from the colon-separated [`NIX_PATH`](@docroot@/command-ref/env-common.md#env-NIX_PATH) environment
-  variable, and is used to look up the location of Nix expressions using [paths](@docroot@/language/types.md#type-path) enclosed in angle
-  brackets (i.e., `<nixpkgs>`).
 
-  For instance, passing
+  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).
-  -I /home/eelco/Dev
-  -I /etc/nixos
-  ```
-
-  will cause Nix to look for paths relative to `/home/eelco/Dev` and
-  `/etc/nixos`, in that order. This is equivalent to setting the
-  `NIX_PATH` environment variable to
-
-  ```
-  /home/eelco/Dev:/etc/nixos
-  ```
-
-  It is also possible to match paths against a prefix. For example,
-  passing
-
-  ```
-  -I nixpkgs=/home/eelco/Dev/nixpkgs-branch
-  -I /etc/nixos
-  ```
-
-  will cause Nix to search for `<nixpkgs/path>` in
-  `/home/eelco/Dev/nixpkgs-branch/path` and `/etc/nixos/nixpkgs/path`.
-
-  If a path in the Nix search path 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 consist of a single
-  top-level directory. For example, passing
-
-  ```
-  -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz
-  ```
-
-  tells Nix to download and use the current contents of the `master`
-  branch in the `nixpkgs` repository.
-
-  The URLs of the tarballs from the official `nixos.org` channels
-  (see [the manual page for `nix-channel`](../nix-channel.md)) can be
-  abbreviated as `channel:<channel-name>`.  For instance, the
-  following two flags are equivalent:
-
-  ```
-  -I nixpkgs=channel:nixos-21.05
-  -I nixpkgs=https://nixos.org/channels/nixos-21.05/nixexprs.tar.xz
-  ```
-
-  You can also fetch source trees using [flake URLs](./nix3-flake.md#url-like-syntax) and add them to the
-  search path. For instance,
-
-  ```
-  -I nixpkgs=flake:nixpkgs
-  ```
-
-  specifies that the prefix `nixpkgs` shall refer to the source tree
-  downloaded from the `nixpkgs` entry in the flake registry. Similarly,
-
-  ```
-  -I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05
-  ```
-
-  makes `<nixpkgs>` refer to a particular branch of the
-  `NixOS/nixpkgs` repository on GitHub.
   )",
         .category = category,
         .labels = {"path"},
@@ -213,7 +149,7 @@ Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
         auto v = state.allocValue();
         std::visit(overloaded {
             [&](const AutoArgExpr & arg) {
-                state.mkThunk_(*v, state.parseExprFromString(arg.expr, state.rootPath(".")));
+                state.mkThunk_(*v, state.parseExprFromString(arg.expr, compatibilitySettings.nixShellShebangArgumentsRelativeToScript ? state.rootPath(absPath(getCommandBaseDir())) : state.rootPath(".")));
             },
             [&](const AutoArgString & arg) {
                 v->mkString(arg.s);

src/libcmd/compatibility-settings.hh

@@ -7,12 +7,29 @@ struct CompatibilitySettings : public Config
 
     CompatibilitySettings() = default;
 
+    // Added in Nix 2.24, July 2024.
     Setting<bool> nixShellAlwaysLooksForShellNix{this, true, "nix-shell-always-looks-for-shell-nix", R"(
         Before Nix 2.24, [`nix-shell`](@docroot@/command-ref/nix-shell.md) would only look at `shell.nix` if it was in the working directory - when no file was specified.
 
         Since Nix 2.24, `nix-shell` always looks for a `shell.nix`, whether that's in the working directory, or in a directory that was passed as an argument.
 
-        You may set this to `false` to revert to the Nix 2.3 behavior.
+        You may set this to `false` to temporarily revert to the behavior of Nix 2.23 and older.
+
+        Using this setting is not recommended.
+        It will be deprecated and removed.
+    )"};
+
+    // Added in Nix 2.24, July 2024.
+    Setting<bool> nixShellShebangArgumentsRelativeToScript{
+        this, true, "nix-shell-shebang-arguments-relative-to-script", R"(
+        Before Nix 2.24, relative file path expressions in arguments in a `nix-shell` shebang were resolved relative to the working directory.
+
+        Since Nix 2.24, `nix-shell` resolves these paths in a manner that is relative to the [base directory](@docroot@/glossary.md#gloss-base-directory), defined as the script's directory.
+
+        You may set this to `false` to temporarily revert to the behavior of Nix 2.23 and older.
+
+        Using this setting is not recommended.
+        It will be deprecated and removed.
     )"};
 };
 

src/libcmd/installable-value.hh

@@ -66,7 +66,7 @@ struct ExtraPathInfoValue : ExtraPathInfo
 };
 
 /**
- * An Installable which corresponds a Nix langauge value, in addition to
+ * An Installable which corresponds a Nix language value, in addition to
  * a collection of \ref DerivedPath "derived paths".
  */
 struct InstallableValue : Installable

src/libcmd/markdown.cc

@@ -1,21 +1,23 @@
 #include "markdown.hh"
-#include "util.hh"
+#include "environment-variables.hh"
+#include "error.hh"
 #include "finally.hh"
 #include "terminal.hh"
 
 #if HAVE_LOWDOWN
-# include <sys/queue.h>
+#  include <sys/queue.h>
-# include <lowdown.h>
+#  include <lowdown.h>
 #endif
 
 namespace nix {
 
-std::string renderMarkdownToTerminal(std::string_view markdown)
-{
 #if HAVE_LOWDOWN
+static std::string doRenderMarkdownToTerminal(std::string_view markdown)
+{
     int windowWidth = getWindowSize().second;
 
-    struct lowdown_opts opts {
+    struct lowdown_opts opts
+    {
         .type = LOWDOWN_TERM,
         .maxdepth = 20,
         .cols = (size_t) std::max(windowWidth - 5, 60),
@@ -51,9 +53,21 @@ std::string renderMarkdownToTerminal(std::string_view markdown)
         throw Error("allocation error while rendering Markdown");
 
     return filterANSIEscapes(std::string(buf->data, buf->size), !isTTY());
-#else
-    return std::string(markdown);
-#endif
 }
 
+std::string renderMarkdownToTerminal(std::string_view markdown)
+{
+    if (auto e = getEnv("_NIX_TEST_RAW_MARKDOWN"); e && *e == "1")
+        return std::string(markdown);
+    else
+        return doRenderMarkdownToTerminal(markdown);
 }
+
+#else
+std::string renderMarkdownToTerminal(std::string_view markdown)
+{
+    return std::string(markdown);
+}
+#endif
+
+} // namespace nix

src/libcmd/markdown.hh

@@ -1,10 +1,17 @@
 #pragma once
 ///@file
 
-#include "types.hh"
+#include <string_view>
 
 namespace nix {
 
+/**
+ * Render the given Markdown text to the terminal.
+ *
+ * If Nix is compiled without Markdown support, this function will return the input text as-is.
+ *
+ * The renderer takes into account the terminal width, and wraps text accordingly.
+ */
 std::string renderMarkdownToTerminal(std::string_view markdown);
 
 }

src/libcmd/meson.build

@@ -30,6 +30,8 @@ deps_public_maybe_subproject = [
 ]
 subdir('build-utils-meson/subprojects')
 
+subdir('build-utils-meson/threads')
+
 nlohmann_json = dependency('nlohmann_json', version : '>= 3.9')
 deps_public += nlohmann_json
 

src/libcmd/package.nix

@@ -93,14 +93,8 @@ mkMesonDerivation (finalAttrs: {
     LDFLAGS = "-fuse-ld=gold";
   };
 
-  enableParallelBuilding = true;
-
   separateDebugInfo = !stdenv.hostPlatform.isStatic;
 
-  # TODO `releaseTools.coverageAnalysis` in Nixpkgs needs to be updated
-  # to work with `strictDeps`.
-  strictDeps = true;
-
   hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
 
   meta = {

src/libcmd/repl-interacter.cc

@@ -19,6 +19,7 @@ extern "C" {
 #include "repl-interacter.hh"
 #include "file-system.hh"
 #include "repl.hh"
+#include "environment-variables.hh"
 
 namespace nix {
 
@@ -34,6 +35,7 @@ void sigintHandler(int signo)
 
 static detail::ReplCompleterMixin * curRepl; // ugly
 
+#ifndef USE_READLINE
 static char * completionCallback(char * s, int * match)
 {
     auto possible = curRepl->completePrefix(s);
@@ -100,6 +102,7 @@ static int listPossibleCallback(char * s, char *** avp)
 
     return ac;
 }
+#endif
 
 ReadlineLikeInteracter::Guard ReadlineLikeInteracter::init(detail::ReplCompleterMixin * repl)
 {
@@ -175,10 +178,23 @@ bool ReadlineLikeInteracter::getLine(std::string & input, ReplPromptType promptT
         return true;
     }
 
+    // editline doesn't echo the input to the output when non-interactive, unlike readline
+    // this results in a different behavior when running tests. The echoing is
+    // quite useful for reading the test output, so we add it here.
+    if (auto e = getEnv("_NIX_TEST_REPL_ECHO"); s && e && *e == "1")
+    {
+#ifndef USE_READLINE
+        // This is probably not right for multi-line input, but we don't use that
+        // in the characterisation tests, so it's fine.
+        std::cout << promptForType(promptType) << s << std::endl;
+#endif
+    }
+
     if (!s)
         return false;
     input += s;
     input += '\n';
+
     return true;
 }
 

src/libcmd/repl.cc

@@ -217,7 +217,7 @@ ReplExitStatus NixRepl::mainLoop()
                 case ProcessLineResult::PromptAgain:
                     break;
                 default:
-                    abort();
+                    unreachable();
             }
         } catch (ParseError & e) {
             if (e.msg().find("unexpected end of file") != std::string::npos) {
@@ -644,9 +644,6 @@ ProcessLineResult NixRepl::processLine(std::string line)
                 fallbackPos = attr->pos;
                 fallbackDoc = state->getDocCommentForPos(fallbackPos);
             }
-
-        } else {
-            evalString(arg, v);
         }
 
         evalString(arg, v);

src/libexpr-c/meson.build

@@ -29,6 +29,8 @@ deps_public_maybe_subproject = [
 ]
 subdir('build-utils-meson/subprojects')
 
+subdir('build-utils-meson/threads')
+
 # TODO rename, because it will conflict with downstream projects
 configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
 

src/libexpr-c/nix_api_expr.cc

@@ -14,10 +14,10 @@
 #include "nix_api_util.h"
 #include "nix_api_util_internal.h"
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
-#include <mutex>
+#  include <mutex>
-#define GC_INCLUDE_NEW 1
+#  define GC_INCLUDE_NEW 1
-#include "gc_cpp.h"
+#  include "gc_cpp.h"
 #endif
 
 nix_err nix_libexpr_init(nix_c_context * context)
@@ -131,7 +131,7 @@ void nix_state_free(EvalState * state)
     delete state;
 }
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
 std::unordered_map<
     const void *,
     unsigned int,
@@ -207,7 +207,7 @@ nix_err nix_value_decref(nix_c_context * context, nix_value *x)
 
 void nix_gc_register_finalizer(void * obj, void * cd, void (*finalizer)(void * obj, void * cd))
 {
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
     GC_REGISTER_FINALIZER(obj, finalizer, cd, 0, 0);
 #endif
 }

src/libexpr-c/nix_api_expr.h

@@ -14,6 +14,16 @@
 #include "nix_api_util.h"
 #include <stddef.h>
 
+#ifndef __has_c_attribute
+#  define __has_c_attribute(x) 0
+#endif
+
+#if __has_c_attribute(deprecated)
+#  define NIX_DEPRECATED(msg) [[deprecated(msg)]]
+#else
+#  define NIX_DEPRECATED(msg)
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -45,7 +55,7 @@ typedef struct EvalState EvalState; // nix::EvalState
  * @see nix_value_incref, nix_value_decref
  */
 typedef struct nix_value nix_value;
-[[deprecated("use nix_value instead")]] typedef nix_value Value;
+NIX_DEPRECATED("use nix_value instead") typedef nix_value Value;
 
 // Function prototypes
 /**

src/libexpr-c/nix_api_external.cc

@@ -14,7 +14,7 @@
 
 #include <nlohmann/json.hpp>
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
 # include "gc/gc.h"
 # define GC_INCLUDE_NEW 1
 # include "gc_cpp.h"
@@ -174,7 +174,7 @@ ExternalValue * nix_create_external_value(nix_c_context * context, NixCExternalV
         context->last_err_code = NIX_OK;
     try {
         auto ret = new
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
             (GC)
 #endif
                 NixCExternalValue(*desc, v);

src/libexpr-c/nix_api_value.cc

@@ -14,7 +14,7 @@
 #include "nix_api_value.h"
 #include "value/context.hh"
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
 #  include "gc/gc.h"
 #  define GC_INCLUDE_NEW 1
 #  include "gc_cpp.h"
@@ -131,7 +131,7 @@ PrimOp * nix_alloc_primop(
     try {
         using namespace std::placeholders;
         auto p = new
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
             (GC)
 #endif
                 nix::PrimOp{

src/libexpr-c/package.nix

@@ -63,12 +63,8 @@ mkMesonDerivation (finalAttrs: {
     LDFLAGS = "-fuse-ld=gold";
   };
 
-  enableParallelBuilding = true;
-
   separateDebugInfo = !stdenv.hostPlatform.isStatic;
 
-  strictDeps = true;
-
   hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
 
   meta = {

src/libexpr/attr-path.cc

@@ -134,7 +134,7 @@ std::pair<SourcePath, uint32_t> findPackageFilename(EvalState & state, Value & v
         return {SourcePath{path.accessor, CanonPath(fn.substr(0, colon))}, lineno};
     } catch (std::invalid_argument & e) {
         fail();
-        abort();
+        unreachable();
     }
 }
 

src/libexpr/eval-cache.cc

@@ -95,7 +95,7 @@ struct AttrDb
     {
         try {
             auto state(_state->lock());
-            if (!failed)
+            if (!failed && state->txn->active)
                 state->txn->commit();
             state->txn.reset();
         } catch (...) {

src/libexpr/eval-error.cc

@@ -92,6 +92,14 @@ void EvalErrorBuilder<T>::debugThrow()
     throw error;
 }
 
+template<class T>
+void EvalErrorBuilder<T>::panic()
+{
+    logError(error.info());
+    printError("This is a bug! An unexpected condition occurred, causing the Nix evaluator to have to stop. If you could share a reproducible example or a core dump, please open an issue at https://github.com/NixOS/nix/issues");
+    abort();
+}
+
 template class EvalErrorBuilder<EvalBaseError>;
 template class EvalErrorBuilder<EvalError>;
 template class EvalErrorBuilder<AssertionError>;

src/libexpr/eval-error.hh

@@ -110,6 +110,12 @@ public:
      * Delete the `EvalErrorBuilder` and throw the underlying exception.
      */
     [[gnu::noinline, gnu::noreturn]] void debugThrow();
+
+    /**
+     * A programming error or fatal condition occurred. Abort the process for core dump and debugging.
+     * This does not print a proper backtrace, because unwinding the stack is destructive.
+     */
+    [[gnu::noinline, gnu::noreturn]] void panic();
 };
 
 }

src/libexpr/eval-gc.cc

@@ -1,5 +1,7 @@
 #include "error.hh"
 #include "environment-variables.hh"
+#include "eval-settings.hh"
+#include "config-global.hh"
 #include "serialise.hh"
 #include "eval-gc.hh"
 
@@ -84,14 +86,17 @@ void fixupBoehmStackPointer(void ** sp_ptr, void * _pthread_id)
 {
     void *& sp = *sp_ptr;
     auto pthread_id = reinterpret_cast<pthread_t>(_pthread_id);
+#  ifndef __APPLE__
     pthread_attr_t pattr;
+#  endif
     size_t osStackSize;
-    void * osStackLow;
+    // The low address of the stack, which grows down.
+    void * osStackLimit;
     void * osStackBase;
 
 #  ifdef __APPLE__
     osStackSize = pthread_get_stacksize_np(pthread_id);
-    osStackLow = pthread_get_stackaddr_np(pthread_id);
+    osStackLimit = pthread_get_stackaddr_np(pthread_id);
 #  else
     if (pthread_attr_init(&pattr)) {
         throw Error("fixupBoehmStackPointer: pthread_attr_init failed");
@@ -110,18 +115,18 @@ void fixupBoehmStackPointer(void ** sp_ptr, void * _pthread_id)
 #    else
 #      error "Need one of `pthread_attr_get_np` or `pthread_getattr_np`"
 #    endif
-    if (pthread_attr_getstack(&pattr, &osStackLow, &osStackSize)) {
+    if (pthread_attr_getstack(&pattr, &osStackLimit, &osStackSize)) {
         throw Error("fixupBoehmStackPointer: pthread_attr_getstack failed");
     }
     if (pthread_attr_destroy(&pattr)) {
         throw Error("fixupBoehmStackPointer: pthread_attr_destroy failed");
     }
 #  endif
-    osStackBase = (char *) osStackLow + osStackSize;
+    osStackBase = (char *) osStackLimit + osStackSize;
     // NOTE: We assume the stack grows down, as it does on all architectures we support.
     //       Architectures that grow the stack up are rare.
-    if (sp >= osStackBase || sp < osStackLow) { // lo is outside the os stack
+    if (sp >= osStackBase || sp < osStackLimit) { // sp is outside the os stack
-        sp = osStackBase;
+        sp = osStackLimit;
     }
 }
 
@@ -155,6 +160,10 @@ static inline void initGCReal()
        there. */
     GC_set_no_dls(1);
 
+    /* Enable perf measurements. This is just a setting; not much of a
+       start of something. */
+    GC_start_performance_measurement();
+
     GC_INIT();
 
     GC_set_oom_fn(oomHandler);
@@ -202,6 +211,14 @@ static inline void initGCReal()
     }
 }
 
+static size_t gcCyclesAfterInit = 0;
+
+size_t getGCCycles()
+{
+    assertGCInitialized();
+    return static_cast<size_t>(GC_get_gc_no()) - gcCyclesAfterInit;
+}
+
 #endif
 
 static bool gcInitialised = false;
@@ -213,8 +230,16 @@ void initGC()
 
 #if HAVE_BOEHMGC
     initGCReal();
+
+    gcCyclesAfterInit = GC_get_gc_no();
 #endif
 
+    // NIX_PATH must override the regular setting
+    // See the comment in applyConfig
+    if (auto nixPathEnv = getEnv("NIX_PATH")) {
+        globalConfig.set("nix-path", concatStringsSep(" ", EvalSettings::parseNixPath(nixPathEnv.value())));
+    }
+
     gcInitialised = true;
 }
 
@@ -223,4 +248,4 @@ void assertGCInitialized()
     assert(gcInitialised);
 }
 
-}
+} // namespace nix

src/libexpr/eval-gc.hh

@@ -1,6 +1,8 @@
 #pragma once
 ///@file
 
+#include <cstddef>
+
 namespace nix {
 
 /**
@@ -13,4 +15,11 @@ void initGC();
  */
 void assertGCInitialized();
 
-}
+#ifdef HAVE_BOEHMGC
+/**
+ * The number of GC cycles since initGC().
+ */
+size_t getGCCycles();
+#endif
+
+} // namespace nix

src/libexpr/eval-settings.cc

@@ -8,7 +8,7 @@ namespace nix {
 
 /* Very hacky way to parse $NIX_PATH, which is colon-separated, but
    can contain URLs (e.g. "nixpkgs=https://bla...:foo=https://"). */
-static Strings parseNixPath(const std::string & s)
+Strings EvalSettings::parseNixPath(const std::string & s)
 {
     Strings res;
 
@@ -48,15 +48,12 @@ EvalSettings::EvalSettings(bool & readOnlyMode, EvalSettings::LookupPathHooks lo
     : readOnlyMode{readOnlyMode}
     , lookupPathHooks{lookupPathHooks}
 {
-    auto var = getEnv("NIX_PATH");
+    auto var = getEnv("NIX_ABORT_ON_WARN");
-    if (var) nixPath = parseNixPath(*var);
-
-    var = getEnv("NIX_ABORT_ON_WARN");
     if (var && (var == "1" || var == "yes" || var == "true"))
         builtinsAbortOnWarn = true;
 }
 
-Strings EvalSettings::getDefaultNixPath() const
+Strings EvalSettings::getDefaultNixPath()
 {
     Strings res;
     auto add = [&](const Path & p, const std::string & s = std::string()) {
@@ -69,11 +66,9 @@ Strings EvalSettings::getDefaultNixPath() const
         }
     };
 
-    if (!restrictEval && !pureEval) {
+    add(getNixDefExpr() + "/channels");
-        add(getNixDefExpr() + "/channels");
+    add(rootChannelsDir() + "/nixpkgs", "nixpkgs");
-        add(rootChannelsDir() + "/nixpkgs", "nixpkgs");
+    add(rootChannelsDir());
-        add(rootChannelsDir());
-    }
 
     return res;
 }

src/libexpr/eval-settings.hh

@@ -43,10 +43,12 @@ struct EvalSettings : Config
 
     bool & readOnlyMode;
 
-    Strings getDefaultNixPath() const;
+    static Strings getDefaultNixPath();
 
     static bool isPseudoUrl(std::string_view s);
 
+    static Strings parseNixPath(const std::string & s);
+
     static std::string resolvePseudoUrl(std::string_view url);
 
     LookupPathHooks lookupPathHooks;
@@ -63,7 +65,7 @@ struct EvalSettings : Config
           extern "C" typedef void (*ValueInitialiser) (EvalState & state, Value & v);
           ```
 
-          The [Nix C++ API documentation](@docroot@/contributing/documentation.md#api-documentation) has more details on evaluator internals.
+          The [Nix C++ API documentation](@docroot@/development/documentation.md#api-documentation) has more details on evaluator internals.
 
         - `builtins.exec` *arguments*
 
@@ -71,25 +73,30 @@ struct EvalSettings : Config
     )"};
 
     Setting<Strings> nixPath{
-        this, getDefaultNixPath(), "nix-path",
+        this, {}, "nix-path",
         R"(
           List of search paths to use for [lookup path](@docroot@/language/constructs/lookup-path.md) resolution.
           This setting determines the value of
           [`builtins.nixPath`](@docroot@/language/builtins.md#builtins-nixPath) and can be used with [`builtins.findFile`](@docroot@/language/builtins.md#builtins-findFile).
 
-          The default value is
+          - The configuration setting is overridden by the [`NIX_PATH`](@docroot@/command-ref/env-common.md#env-NIX_PATH)
+          environment variable.
+          - `NIX_PATH` is overridden by [specifying the setting as the command line flag](@docroot@/command-ref/conf-file.md#command-line-flags) `--nix-path`.
+          - Any current value is extended by the [`-I` option](@docroot@/command-ref/opt-common.md#opt-I) or `--extra-nix-path`.
 
-          ```
+          If the respective paths are accessible, the default values are:
-          $HOME/.nix-defexpr/channels
-          nixpkgs=$NIX_STATE_DIR/profiles/per-user/root/channels/nixpkgs
-          $NIX_STATE_DIR/profiles/per-user/root/channels
-          ```
 
-          It can be overridden with the [`NIX_PATH` environment variable](@docroot@/command-ref/env-common.md#env-NIX_PATH) or the [`-I` command line option](@docroot@/command-ref/opt-common.md#opt-I).
+          - `$HOME/.nix-defexpr/channels`
+          - `nixpkgs=$NIX_STATE_DIR/profiles/per-user/root/channels/nixpkgs`
+          - `$NIX_STATE_DIR/profiles/per-user/root/channels`
+
+          See [`NIX_STATE_DIR`](@docroot@/command-ref/env-common.md#env-NIX_STATE_DIR) for details.
 
           > **Note**
           >
-          > If [pure evaluation](#conf-pure-eval) is enabled, `nixPath` evaluates to the empty list `[ ]`.
+          > If [restricted evaluation](@docroot@/command-ref/conf-file.md#conf-restrict-eval) is enabled, the default value is empty.
+          >
+          > If [pure evaluation](#conf-pure-eval) is enabled, `builtins.nixPath` *always* evaluates to the empty list `[ ]`.
         )", {}, false};
 
     Setting<std::string> currentSystem{

src/libexpr/eval.cc

@@ -149,7 +149,7 @@ std::string_view showType(ValueType type, bool withArticle)
         case nFloat: return WA("a", "float");
         case nThunk: return WA("a", "thunk");
     }
-    abort();
+    unreachable();
 }
 
 
@@ -215,7 +215,7 @@ static Symbol getName(const AttrName & name, EvalState & state, Env & env)
 static constexpr size_t BASE_ENV_SIZE = 128;
 
 EvalState::EvalState(
-    const LookupPath & _lookupPath,
+    const LookupPath & lookupPathFromArguments,
     ref<Store> store,
     const fetchers::Settings & fetchSettings,
     const EvalSettings & settings,
@@ -331,12 +331,21 @@ EvalState::EvalState(
     vStringSymlink.mkString("symlink");
     vStringUnknown.mkString("unknown");
 
-    /* Initialise the Nix expression search path. */
+    /* Construct the Nix expression search path. */
+    assert(lookupPath.elements.empty());
     if (!settings.pureEval) {
-        for (auto & i : _lookupPath.elements)
+        for (auto & i : lookupPathFromArguments.elements) {
             lookupPath.elements.emplace_back(LookupPath::Elem {i});
-        for (auto & i : settings.nixPath.get())
+        }
+        /* $NIX_PATH overriding regular settings is implemented as a hack in `initGC()` */
+        for (auto & i : settings.nixPath.get()) {
             lookupPath.elements.emplace_back(LookupPath::Elem::parse(i));
+        }
+        if (!settings.restrictEval) {
+            for (auto & i : EvalSettings::getDefaultNixPath()) {
+                lookupPath.elements.emplace_back(LookupPath::Elem::parse(i));
+            }
+        }
     }
 
     /* Allow access to all paths in the search path. */
@@ -771,7 +780,7 @@ void EvalState::runDebugRepl(const Error * error, const Env & env, const Expr &
             case ReplExitStatus::Continue:
                 break;
             default:
-                abort();
+                unreachable();
         }
     }
 }
@@ -1140,7 +1149,7 @@ inline void EvalState::evalAttrs(Env & env, Expr * e, Value & v, const PosIdx po
 
 void Expr::eval(EvalState & state, Env & env, Value & v)
 {
-    abort();
+    unreachable();
 }
 
 
@@ -1573,7 +1582,7 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
                                 .withFrame(*fun.payload.lambda.env, lambda)
                                 .debugThrow();
                         }
-                    abort(); // can't happen
+                    unreachable();
                 }
             }
 
@@ -1825,9 +1834,24 @@ void ExprIf::eval(EvalState & state, Env & env, Value & v)
 void ExprAssert::eval(EvalState & state, Env & env, Value & v)
 {
     if (!state.evalBool(env, cond, pos, "in the condition of the assert statement")) {
-        std::ostringstream out;
+        auto exprStr = ({
-        cond->show(state.symbols, out);
+            std::ostringstream out;
-        state.error<AssertionError>("assertion '%1%' failed", out.str()).atPos(pos).withFrame(env, *this).debugThrow();
+            cond->show(state.symbols, out);
+            out.str();
+        });
+
+        if (auto eq = dynamic_cast<ExprOpEq *>(cond)) {
+            try {
+                Value v1; eq->e1->eval(state, env, v1);
+                Value v2; eq->e2->eval(state, env, v2);
+                state.assertEqValues(v1, v2, eq->pos, "in an equality assertion");
+            } catch (AssertionError & e) {
+                e.addTrace(state.positions[pos], "while evaluating the condition of the assertion '%s'", exprStr);
+                throw;
+            }
+        }
+
+        state.error<AssertionError>("assertion '%1%' failed", exprStr).atPos(pos).withFrame(env, *this).debugThrow();
     }
     body->eval(state, env, v);
 }
@@ -2484,6 +2508,214 @@ SingleDerivedPath EvalState::coerceToSingleDerivedPath(const PosIdx pos, Value &
 }
 
 
+
+// NOTE: This implementation must match eqValues!
+// We accept this burden because informative error messages for
+// `assert a == b; x` are critical for our users' testing UX.
+void EvalState::assertEqValues(Value & v1, Value & v2, const PosIdx pos, std::string_view errorCtx)
+{
+    // This implementation must match eqValues.
+    forceValue(v1, pos);
+    forceValue(v2, pos);
+
+    if (&v1 == &v2)
+        return;
+
+    // Special case type-compatibility between float and int
+    if ((v1.type() == nInt || v1.type() == nFloat) && (v2.type() == nInt || v2.type() == nFloat)) {
+        if (eqValues(v1, v2, pos, errorCtx)) {
+            return;
+        } else {
+            error<AssertionError>(
+                "%s with value '%s' is not equal to %s with value '%s'",
+                showType(v1),
+                ValuePrinter(*this, v1, errorPrintOptions),
+                showType(v2),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+    }
+
+    if (v1.type() != v2.type()) {
+        error<AssertionError>(
+            "%s of value '%s' is not equal to %s of value '%s'",
+            showType(v1),
+            ValuePrinter(*this, v1, errorPrintOptions),
+            showType(v2),
+            ValuePrinter(*this, v2, errorPrintOptions))
+            .debugThrow();
+    }
+
+    switch (v1.type()) {
+    case nInt:
+        if (v1.integer() != v2.integer()) {
+            error<AssertionError>("integer '%d' is not equal to integer '%d'", v1.integer(), v2.integer()).debugThrow();
+        }
+        return;
+
+    case nBool:
+        if (v1.boolean() != v2.boolean()) {
+            error<AssertionError>(
+                "boolean '%s' is not equal to boolean '%s'",
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+        return;
+
+    case nString:
+        if (strcmp(v1.c_str(), v2.c_str()) != 0) {
+            error<AssertionError>(
+                "string '%s' is not equal to string '%s'",
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+        return;
+
+    case nPath:
+        if (v1.payload.path.accessor != v2.payload.path.accessor) {
+            error<AssertionError>(
+                "path '%s' is not equal to path '%s' because their accessors are different",
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+        if (strcmp(v1.payload.path.path, v2.payload.path.path) != 0) {
+            error<AssertionError>(
+                "path '%s' is not equal to path '%s'",
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+        return;
+
+    case nNull:
+        return;
+
+    case nList:
+        if (v1.listSize() != v2.listSize()) {
+            error<AssertionError>(
+                "list of size '%d' is not equal to list of size '%d', left hand side is '%s', right hand side is '%s'",
+                v1.listSize(),
+                v2.listSize(),
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+        for (size_t n = 0; n < v1.listSize(); ++n) {
+            try {
+                assertEqValues(*v1.listElems()[n], *v2.listElems()[n], pos, errorCtx);
+            } catch (Error & e) {
+                e.addTrace(positions[pos], "while comparing list element %d", n);
+                throw;
+            }
+        }
+        return;
+
+    case nAttrs: {
+        if (isDerivation(v1) && isDerivation(v2)) {
+            auto i = v1.attrs()->get(sOutPath);
+            auto j = v2.attrs()->get(sOutPath);
+            if (i && j) {
+                try {
+                    assertEqValues(*i->value, *j->value, pos, errorCtx);
+                    return;
+                } catch (Error & e) {
+                    e.addTrace(positions[pos], "while comparing a derivation by its '%s' attribute", "outPath");
+                    throw;
+                }
+                assert(false);
+            }
+        }
+
+        if (v1.attrs()->size() != v2.attrs()->size()) {
+            error<AssertionError>(
+                "attribute names of attribute set '%s' differs from attribute set '%s'",
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+
+        // Like normal comparison, we compare the attributes in non-deterministic Symbol index order.
+        // This function is called when eqValues has found a difference, so to reliably
+        // report about its result, we should follow in its literal footsteps and not
+        // try anything fancy that could lead to an error.
+        Bindings::const_iterator i, j;
+        for (i = v1.attrs()->begin(), j = v2.attrs()->begin(); i != v1.attrs()->end(); ++i, ++j) {
+            if (i->name != j->name) {
+                // A difference in a sorted list means that one attribute is not contained in the other, but we don't
+                // know which. Let's find out. Could use <, but this is more clear.
+                if (!v2.attrs()->get(i->name)) {
+                    error<AssertionError>(
+                        "attribute name '%s' is contained in '%s', but not in '%s'",
+                        symbols[i->name],
+                        ValuePrinter(*this, v1, errorPrintOptions),
+                        ValuePrinter(*this, v2, errorPrintOptions))
+                        .debugThrow();
+                }
+                if (!v1.attrs()->get(j->name)) {
+                    error<AssertionError>(
+                        "attribute name '%s' is missing in '%s', but is contained in '%s'",
+                        symbols[j->name],
+                        ValuePrinter(*this, v1, errorPrintOptions),
+                        ValuePrinter(*this, v2, errorPrintOptions))
+                        .debugThrow();
+                }
+                assert(false);
+            }
+            try {
+                assertEqValues(*i->value, *j->value, pos, errorCtx);
+            } catch (Error & e) {
+                // The order of traces is reversed, so this presents as
+                //  where left hand side is
+                //    at <pos>
+                //  where right hand side is
+                //    at <pos>
+                //  while comparing attribute '<name>'
+                if (j->pos != noPos)
+                    e.addTrace(positions[j->pos], "where right hand side is");
+                if (i->pos != noPos)
+                    e.addTrace(positions[i->pos], "where left hand side is");
+                e.addTrace(positions[pos], "while comparing attribute '%s'", symbols[i->name]);
+                throw;
+            }
+        }
+        return;
+    }
+
+    case nFunction:
+        error<AssertionError>("distinct functions and immediate comparisons of identical functions compare as unequal")
+            .debugThrow();
+
+    case nExternal:
+        if (!(*v1.external() == *v2.external())) {
+            error<AssertionError>(
+                "external value '%s' is not equal to external value '%s'",
+                ValuePrinter(*this, v1, errorPrintOptions),
+                ValuePrinter(*this, v2, errorPrintOptions))
+                .debugThrow();
+        }
+        return;
+
+    case nFloat:
+        // !!!
+        if (!(v1.fpoint() == v2.fpoint())) {
+            error<AssertionError>("float '%f' is not equal to float '%f'", v1.fpoint(), v2.fpoint()).debugThrow();
+        }
+        return;
+
+    case nThunk: // Must not be left by forceValue
+        assert(false);
+    default: // Note that we pass compiler flags that should make `default:` unreachable.
+        // Also note that this probably ran after `eqValues`, which implements
+        // the same logic more efficiently (without having to unwind stacks),
+        // so maybe `assertEqValues` and `eqValues` are out of sync. Check it for solutions.
+        error<EvalError>("assertEqValues: cannot compare %1% with %2%", showType(v1), showType(v2)).withTrace(pos, errorCtx).panic();
+    }
+}
+
+// This implementation must match assertEqValues
 bool EvalState::eqValues(Value & v1, Value & v2, const PosIdx pos, std::string_view errorCtx)
 {
     forceValue(v1, pos);
@@ -2557,11 +2789,13 @@ bool EvalState::eqValues(Value & v1, Value & v2, const PosIdx pos, std::string_v
             return *v1.external() == *v2.external();
 
         case nFloat:
+            // !!!
             return v1.fpoint() == v2.fpoint();
 
         case nThunk: // Must not be left by forceValue
-        default:
+            assert(false);
-            error<EvalError>("cannot compare %1% with %2%", showType(v1), showType(v2)).withTrace(pos, errorCtx).debugThrow();
+        default: // Note that we pass compiler flags that should make `default:` unreachable.
+            error<EvalError>("eqValues: cannot compare %1% with %2%", showType(v1), showType(v2)).withTrace(pos, errorCtx).panic();
     }
 }
 
@@ -2610,6 +2844,11 @@ void EvalState::printStatistics()
 #if HAVE_BOEHMGC
     GC_word heapSize, totalBytes;
     GC_get_heap_usage_safe(&heapSize, 0, 0, 0, &totalBytes);
+    double gcFullOnlyTime = ({
+        auto ms = GC_get_full_gc_total_time();
+        ms * 0.001;
+    });
+    auto gcCycles = getGCCycles();
 #endif
 
     auto outPath = getEnv("NIX_SHOW_STATS_PATH").value_or("-");
@@ -2620,6 +2859,15 @@ void EvalState::printStatistics()
 #ifndef _WIN32 // TODO implement
     topObj["cpuTime"] = cpuTime;
 #endif
+    topObj["time"] = {
+#ifndef _WIN32 // TODO implement
+        {"cpu", cpuTime},
+#endif
+#if HAVE_BOEHMGC
+        {GC_is_incremental_mode() ? "gcNonIncremental" : "gc", gcFullOnlyTime},
+        {GC_is_incremental_mode() ? "gcNonIncrementalFraction" : "gcFraction", gcFullOnlyTime / cpuTime},
+#endif
+    };
     topObj["envs"] = {
         {"number", nrEnvs},
         {"elements", nrValuesInEnvs},
@@ -2661,6 +2909,7 @@ void EvalState::printStatistics()
     topObj["gc"] = {
         {"heapSize", heapSize},
         {"totalBytes", totalBytes},
+        {"cycles", gcCycles},
     };
 #endif
 

src/libexpr/eval.hh

@@ -130,7 +130,7 @@ struct Constant
     typedef std::map<std::string, Value *> ValMap;
 #endif
 
-typedef std::map<PosIdx, DocComment> DocCommentMap;
+typedef std::unordered_map<PosIdx, DocComment> DocCommentMap;
 
 struct Env
 {
@@ -335,7 +335,7 @@ private:
      * Associate source positions of certain AST nodes with their preceding doc comment, if they have one.
      * Grouped by file.
      */
-    std::map<SourcePath, DocCommentMap> positionToDocComment;
+    std::unordered_map<SourcePath, DocCommentMap> positionToDocComment;
 
     LookupPath lookupPath;
 
@@ -655,6 +655,15 @@ public:
      */
     bool eqValues(Value & v1, Value & v2, const PosIdx pos, std::string_view errorCtx);
 
+    /**
+     * Like `eqValues`, but throws an `AssertionError` if not equal.
+     *
+     * WARNING:
+     * Callers should call `eqValues` first and report if `assertEqValues` behaves
+     * incorrectly. (e.g. if it doesn't throw if eqValues returns false or vice versa)
+     */
+    void assertEqValues(Value & v1, Value & v2, const PosIdx pos, std::string_view errorCtx);
+
     bool isFunctor(Value & fun);
 
     // FIXME: use std::span

src/libexpr/json-to-value.cc

@@ -42,7 +42,7 @@ class JSONSax : nlohmann::json_sax<json> {
             auto attrs2 = state.buildBindings(attrs.size());
             for (auto & i : attrs)
                 attrs2.insert(i.first, i.second);
-            parent->value(state).mkAttrs(attrs2.alreadySorted());
+            parent->value(state).mkAttrs(attrs2);
             return std::move(parent);
         }
         void add() override { v = nullptr; }
@@ -80,42 +80,42 @@ class JSONSax : nlohmann::json_sax<json> {
 public:
     JSONSax(EvalState & state, Value & v) : state(state), rs(new JSONState(&v)) {};
 
-    bool null()
+    bool null() override
     {
         rs->value(state).mkNull();
         rs->add();
         return true;
     }
 
-    bool boolean(bool val)
+    bool boolean(bool val) override
     {
         rs->value(state).mkBool(val);
         rs->add();
         return true;
     }
 
-    bool number_integer(number_integer_t val)
+    bool number_integer(number_integer_t val) override
     {
         rs->value(state).mkInt(val);
         rs->add();
         return true;
     }
 
-    bool number_unsigned(number_unsigned_t val)
+    bool number_unsigned(number_unsigned_t val) override
     {
         rs->value(state).mkInt(val);
         rs->add();
         return true;
     }
 
-    bool number_float(number_float_t val, const string_t & s)
+    bool number_float(number_float_t val, const string_t & s) override
     {
         rs->value(state).mkFloat(val);
         rs->add();
         return true;
     }
 
-    bool string(string_t & val)
+    bool string(string_t & val) override
     {
         rs->value(state).mkString(val);
         rs->add();
@@ -123,7 +123,7 @@ public:
     }
 
 #if NLOHMANN_JSON_VERSION_MAJOR >= 3 && NLOHMANN_JSON_VERSION_MINOR >= 8
-    bool binary(binary_t&)
+    bool binary(binary_t&) override
     {
         // This function ought to be unreachable
         assert(false);
@@ -131,35 +131,35 @@ public:
     }
 #endif
 
-    bool start_object(std::size_t len)
+    bool start_object(std::size_t len) override
     {
         rs = std::make_unique<JSONObjectState>(std::move(rs));
         return true;
     }
 
-    bool key(string_t & name)
+    bool key(string_t & name) override
     {
         dynamic_cast<JSONObjectState*>(rs.get())->key(name, state);
         return true;
     }
 
-    bool end_object() {
+    bool end_object() override {
         rs = rs->resolve(state);
         rs->add();
         return true;
     }
 
-    bool end_array() {
+    bool end_array() override {
         return end_object();
     }
 
-    bool start_array(size_t len) {
+    bool start_array(size_t len) override {
         rs = std::make_unique<JSONListState>(std::move(rs),
             len != std::numeric_limits<size_t>::max() ? len : 128);
         return true;
     }
 
-    bool parse_error(std::size_t, const std::string&, const nlohmann::detail::exception& ex) {
+    bool parse_error(std::size_t, const std::string&, const nlohmann::detail::exception& ex) override {
         throw JSONParseError("%s", ex.what());
     }
 };

src/libexpr/lexer.l

@@ -67,6 +67,14 @@ static StringToken unescapeStr(SymbolTable & symbols, char * s, size_t length)
     return {result, size_t(t - result)};
 }
 
+static void requireExperimentalFeature(const ExperimentalFeature & feature, const Pos & pos)
+{
+    if (!experimentalFeatureSettings.isEnabled(feature))
+        throw ParseError(ErrorInfo{
+            .msg = HintFmt("experimental Nix feature '%1%' is disabled; add '--extra-experimental-features %1%' to enable it", showExperimentalFeature(feature)),
+            .pos = pos,
+        });
+}
 
 }
 
@@ -119,6 +127,12 @@ or          { return OR_KW; }
 \-\>        { return IMPL; }
 \/\/        { return UPDATE; }
 \+\+        { return CONCAT; }
+\<\|        { requireExperimentalFeature(Xp::PipeOperators, state->positions[CUR_POS]);
+              return PIPE_FROM;
+            }
+\|\>        { requireExperimentalFeature(Xp::PipeOperators, state->positions[CUR_POS]);
+              return PIPE_INTO;
+            }
 
 {ID}        { yylval->id = {yytext, (size_t) yyleng}; return ID; }
 {INT}       { errno = 0;

src/libexpr/meson.build

@@ -32,6 +32,7 @@ subdir('build-utils-meson/threads')
 boost = dependency(
   'boost',
   modules : ['container', 'context'],
+  include_type: 'system',
 )
 # boost is a public dependency, but not a pkg-config dependency unfortunately, so we
 # put in `deps_other`.
@@ -55,7 +56,12 @@ if bdw_gc.found()
 endif
 configdata.set('HAVE_BOEHMGC', bdw_gc.found().to_int())
 
-toml11 = dependency('toml11', version : '>=3.7.0', method : 'cmake')
+toml11 = dependency(
+  'toml11',
+  version : '>=3.7.0',
+  method : 'cmake',
+  include_type: 'system',
+)
 deps_other += toml11
 
 config_h = configure_file(

src/libexpr/nixexpr.cc

@@ -25,7 +25,7 @@ std::ostream & operator <<(std::ostream & str, const SymbolStr & symbol)
 
 void Expr::show(const SymbolTable & symbols, std::ostream & str) const
 {
-    abort();
+    unreachable();
 }
 
 void ExprInt::show(const SymbolTable & symbols, std::ostream & str) const
@@ -82,7 +82,9 @@ void ExprAttrs::showBindings(const SymbolTable & symbols, std::ostream & str) co
         return sa < sb;
     });
     std::vector<Symbol> inherits;
-    std::map<ExprInheritFrom *, std::vector<Symbol>> inheritsFrom;
+    // We can use the displacement as a proxy for the order in which the symbols were parsed.
+    // The assignment of displacements should be deterministic, so that showBindings is deterministic.
+    std::map<Displacement, std::vector<Symbol>> inheritsFrom;
     for (auto & i : sorted) {
         switch (i->second.kind) {
         case AttrDef::Kind::Plain:
@@ -93,7 +95,7 @@ void ExprAttrs::showBindings(const SymbolTable & symbols, std::ostream & str) co
         case AttrDef::Kind::InheritedFrom: {
             auto & select = dynamic_cast<ExprSelect &>(*i->second.e);
             auto & from = dynamic_cast<ExprInheritFrom &>(*select.e);
-            inheritsFrom[&from].push_back(i->first);
+            inheritsFrom[from.displ].push_back(i->first);
             break;
         }
         }
@@ -105,7 +107,7 @@ void ExprAttrs::showBindings(const SymbolTable & symbols, std::ostream & str) co
     }
     for (const auto & [from, syms] : inheritsFrom) {
         str << "inherit (";
-        (*inheritFromExprs)[from->displ]->show(symbols, str);
+        (*inheritFromExprs)[from]->show(symbols, str);
         str << ")";
         for (auto sym : syms) str << " " << symbols[sym];
         str << "; ";
@@ -269,7 +271,7 @@ std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
 
 void Expr::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)
 {
-    abort();
+    unreachable();
 }
 
 void ExprInt::bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env)

src/libexpr/nixexpr.hh

@@ -186,7 +186,7 @@ struct ExprInheritFrom : ExprVar
         this->fromWith = nullptr;
     }
 
-    void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env);
+    void bindVars(EvalState & es, const std::shared_ptr<const StaticEnv> & env) override;
 };
 
 struct ExprSelect : Expr

src/libexpr/package.nix

@@ -102,12 +102,8 @@ mkMesonDerivation (finalAttrs: {
     LDFLAGS = "-fuse-ld=gold";
   };
 
-  enableParallelBuilding = true;
-
   separateDebugInfo = !stdenv.hostPlatform.isStatic;
 
-  strictDeps = true;
-
   hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
 
   meta = {