Merge pull request #214304 from obsidiansystems/pkg-config-meta (6d0b3086) · Commits · nix / nixpkgs

doc/languages-frameworks/pkg-config.section.md

+45 −3

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		@@ -4,6 +4,48 @@

		Nixpkgs provides a couple of facilities for working with this tool.

		- A [setup hook](#setup-hook-pkg-config) bundled with in the `pkg-config` package, to bring a derivation's declared build inputs into the environment.
		- The [`validatePkgConfig` setup hook](https://nixos.org/manual/nixpkgs/stable/#validatepkgconfig), for packages that provide pkg-config modules.
		- The `defaultPkgConfigPackages` package set: a set of aliases, named after the modules they provide. This is meant to be used by language-to-nix integrations. Hand-written packages should use the normal Nixpkgs attribute name instead.
		## Writing packages providing pkg-config modules

		Packages should set `meta.pkgConfigProvides` with the list of package config modules they provide.
		They should also use `testers.testMetaPkgConfig` to check that the final built package matches that list.
		Additionally, the [`validatePkgConfig` setup hook](https://nixos.org/manual/nixpkgs/stable/#validatepkgconfig), will do extra checks on to-be-installed pkg-config modules.

		A good example of all these things is zlib:

		```
		{ pkg-config, testers, ... }:

		stdenv.mkDerivation (finalAttrs: {
		...

		nativeBuildInputs = [ pkg-config validatePkgConfig ];

		passthru.tests.pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;

		meta = {
		...
		pkgConfigModules = [ "zlib" ];
		};
		})
		```

		## Accessing packages via pkg-config module name

		### Within Nixpkgs

		A [setup hook](#setup-hook-pkg-config) is bundled in the `pkg-config` package to bring a derivation's declared build inputs into the environment.
		This will populate environment variables like `PKG_CONFIG_PATH`, `PKG_CONFIG_PATH_FOR_BUILD`, and `PKG_CONFIG_PATH_HOST` based on:

		- how `pkg-config` itself is depended upon

		- how other dependencies are depended upon

		For more details see the section on [specifying dependencies in general](#ssec-stdenv-dependencies).

		Normal pkg-config commands to look up dependencies by name will then work with those environment variables defined by the hook.

		### Externally

		The `defaultPkgConfigPackages` package set is a set of aliases, named after the modules they provide.
		This is meant to be used by language-to-nix integrations.
		Hand-written packages should use the normal Nixpkgs attribute name instead.

pkgs/build-support/testers/default.nix

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		@@ -123,4 +123,5 @@

		hasPkgConfigModule = callPackage ./hasPkgConfigModule/tester.nix { };

		testMetaPkgConfig = callPackage ./testMetaPkgConfig/tester.nix { };
		}

pkgs/build-support/testers/testMetaPkgConfig/tester.nix

0 → 100644

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		{ lib, runCommand, testers }:

		package:

		runCommand "check-meta-pkg-config-modules-for-${package.name}" {
		meta = {
		description = "Test whether ${package.name} exposes all pkg-config modules ${toString package.meta.pkgConfigModules}";
		};
		dependsOn = map
		(moduleName: testers.hasPkgConfigModule { inherit package moduleName; })
		package.meta.pkgConfigModules;
		} ''
		echo "found all of ${toString package.meta.pkgConfigModules}" > "$out"
		''

pkgs/development/libraries/zlib/default.nix

+9 −3

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		@@ -8,6 +8,7 @@
		# the `.pc` file lists only the main output's lib dir.
		# If false, and if `{ static = true; }`, the .a stays in the main output.
		, splitStaticOutput ? shared && static
		, testers
		}:

		# Without either the build will actually still succeed because the build
		@@ -21,11 +22,13 @@ assert shared \|\| static;

		assert splitStaticOutput -> static;

		stdenv.mkDerivation rec {
		stdenv.mkDerivation (finalAttrs: {
		pname = "zlib";
		version = "1.2.13";

		src = fetchurl {
		src = let
		inherit (finalAttrs) version;
		in fetchurl {
		urls = [
		# This URL works for 1.2.13 only; hopefully also for future releases.
		"https://github.com/madler/zlib/releases/download/v${version}/zlib-${version}.tar.gz"
		@@ -125,10 +128,13 @@ stdenv.mkDerivation rec {
		"SHARED_MODE=1"
		];

		passthru.tests.pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;

		meta = with lib; {
		homepage = "https://zlib.net";
		description = "Lossless data-compression library";
		license = licenses.zlib;
		platforms = platforms.all;
		pkgConfigModules = [ "zlib" ];
		};
		}
		})

pkgs/stdenv/generic/check-meta.nix

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		@@ -271,6 +271,7 @@ let
		sourceProvenance = listOf lib.types.attrs;
		maintainers = listOf (attrsOf anything); # TODO use the maintainer type from lib/tests/maintainer-module.nix
		priority = int;
		pkgConfigModules = listOf str;
		platforms = listOf (either str (attrsOf anything)); # see lib.meta.platformMatch
		hydraPlatforms = listOf str;
		broken = bool;