Meson build for libexpr and libflake

meson.build

@@ -9,13 +9,19 @@ project('nix-dev-shell', 'cpp',
 subproject('libutil')
 subproject('libstore')
 subproject('libfetchers')
-subproject('perl')
+subproject('libexpr')
+subproject('libflake')
+
+# Docs
 subproject('internal-api-docs')
 subproject('external-api-docs')
 
 # C wrappers
 subproject('libutil-c')
 
+# Language Bindings
+subproject('perl')
+
 # Testing
 subproject('libutil-test-support')
 subproject('libutil-test')

packaging/components.nix

@@ -19,10 +19,13 @@ in
 
   nix-fetchers = callPackage ../src/libfetchers/package.nix { };
 
-  nix-perl-bindings = callPackage ../src/perl/package.nix { };
+  nix-expr = callPackage ../src/libexpr/package.nix { };
+
+  nix-flake = callPackage ../src/libflake/package.nix { };
 
   nix-internal-api-docs = callPackage ../src/internal-api-docs/package.nix { };
 
   nix-external-api-docs = callPackage ../src/external-api-docs/package.nix { };
 
+  nix-perl-bindings = callPackage ../src/perl/package.nix { };
 }

src/libexpr/.version

@@ -0,0 +1 @@
+../../.version

src/libexpr/meson.build

@@ -0,0 +1,254 @@
+project('nix-expr', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+# See note in ../nix-util/meson.build
+deps_private = [ ]
+
+# See note in ../nix-util/meson.build
+deps_public = [ ]
+
+# See note in ../nix-util/meson.build
+deps_public_subproject = [ ]
+
+# See note in ../nix-util/meson.build
+deps_other = [ ]
+
+configdata = configuration_data()
+
+foreach nix_dep : [
+  dependency('nix-util'),
+  dependency('nix-store'),
+  dependency('nix-fetchers'),
+]
+  if nix_dep.type_name() == 'internal'
+    deps_public_subproject += nix_dep
+    # subproject sadly no good for pkg-config module
+    deps_other += nix_dep
+  else
+    deps_public += nix_dep
+  endif
+endforeach
+
+# This is only conditional to work around
+# https://github.com/mesonbuild/meson/issues/13293. It should be
+# unconditional.
+if not (host_machine.system() == 'windows' and cxx.get_id() == 'gcc')
+  deps_private += dependency('threads')
+endif
+
+boost = dependency(
+  'boost',
+  modules : ['container', 'context'],
+)
+# boost is a public dependency, but not a pkg-config dependency unfortunately, so we
+# put in `deps_other`.
+deps_other += boost
+
+nlohmann_json = dependency('nlohmann_json', version : '>= 3.9')
+deps_public += nlohmann_json
+
+bdw_gc = dependency('bdw-gc', required : get_option('gc'))
+if bdw_gc.found()
+  deps_public += bdw_gc
+  foreach funcspec : [
+    'pthread_attr_get_np',
+    'pthread_getattr_np',
+  ]
+    define_name = 'HAVE_' + funcspec.underscorify().to_upper()
+    define_value = cxx.has_function(funcspec).to_int()
+    configdata.set(define_name, define_value)
+  endforeach
+  configdata.set('GC_THREADS', 1)
+endif
+configdata.set('HAVE_BOEHMGC', bdw_gc.found().to_int())
+
+config_h = configure_file(
+  configuration : configdata,
+  output : 'config-expr.h',
+)
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.h',
+  '-include', 'config-store.h',
+  # '-include', 'config-fetchers.h',
+  '-include', 'config-expr.h',
+  '-Wno-deprecated-declarations',
+  '-Wimplicit-fallthrough',
+  '-Werror=switch',
+  '-Werror=switch-enum',
+  '-Wdeprecated-copy',
+  '-Wignored-qualifiers',
+  # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
+  # at ~1% overhead in `nix search`.
+  #
+  # FIXME: remove when we get meson 1.4.0 which will default this to on for us:
+  # https://mesonbuild.com/Release-notes-for-1-4-0.html#ndebug-setting-now-controls-c-stdlib-assertions
+  '-D_GLIBCXX_ASSERTIONS=1',
+  language : 'cpp',
+)
+
+parser_tab = custom_target(
+  input : 'parser.y',
+  output : [
+    'parser-tab.cc',
+    'parser-tab.hh',
+  ],
+  command : [
+    'bison',
+    '-v',
+    '-o',
+    '@OUTPUT0@',
+    '@INPUT@',
+    '-d',
+  ],
+  # NOTE(Qyriad): Meson doesn't support installing only part of a custom target, so we add
+  # an install script below which removes parser-tab.cc.
+  install : true,
+  install_dir : get_option('includedir') / 'nix',
+)
+
+lexer_tab = custom_target(
+  input : [
+    'lexer.l',
+    parser_tab,
+  ],
+  output : [
+    'lexer-tab.cc',
+    'lexer-tab.hh',
+  ],
+  command : [
+    'flex',
+    '--outfile',
+    '@OUTPUT0@',
+    '--header-file=' + '@OUTPUT1@',
+    '@INPUT0@',
+  ],
+  # NOTE(Qyriad): Meson doesn't support installing only part of a custom target, so we add
+  # an install script below which removes lexer-tab.cc.
+  install : true,
+  install_dir : get_option('includedir') / 'nix',
+)
+
+generated_headers = []
+foreach header : [
+  'imported-drv-to-derivation.nix',
+  'fetchurl.nix',
+  'flake/call-flake.nix',
+  'primops/derivation.nix',
+]
+  generated_headers += custom_target(
+    command : [ 'bash', '-c', '{ echo \'R"__NIX_STR(\' && cat @INPUT@ && echo \')__NIX_STR"\'; } > "$1"', '_ignored_argv0', '@OUTPUT@' ],
+    input : header,
+    output : '@PLAINNAME@.gen.hh',
+  )
+endforeach
+
+
+sources = files(
+  'attr-path.cc',
+  'attr-set.cc',
+  'eval-cache.cc',
+  'eval-error.cc',
+  'eval-gc.cc',
+  'eval-settings.cc',
+  'eval.cc',
+  'function-trace.cc',
+  'get-drvs.cc',
+  'json-to-value.cc',
+  'nixexpr.cc',
+  'paths.cc',
+  'primops.cc',
+  'primops/context.cc',
+  'primops/fetchClosure.cc',
+  'primops/fetchMercurial.cc',
+  'primops/fetchTree.cc',
+  'primops/fromTOML.cc',
+  'print-ambiguous.cc',
+  'print.cc',
+  'search-path.cc',
+  'value-to-json.cc',
+  'value-to-xml.cc',
+  'value/context.cc',
+)
+
+headers = [config_h] + files(
+  'attr-path.hh',
+  'attr-set.hh',
+  'eval-cache.hh',
+  'eval-error.hh',
+  'eval-gc.hh',
+  'eval-inline.hh',
+  'eval-settings.hh',
+  'eval.hh',
+  'function-trace.hh',
+  'gc-small-vector.hh',
+  'get-drvs.hh',
+  'json-to-value.hh',
+  'nixexpr.hh',
+  'parser-state.hh',
+  'pos-idx.hh',
+  'pos-table.hh',
+  'primops.hh',
+  'print-ambiguous.hh',
+  'print-options.hh',
+  'print.hh',
+  'repl-exit-status.hh',
+  'search-path.hh',
+  'symbol-table.hh',
+  'value-to-json.hh',
+  'value-to-xml.hh',
+  'value.hh',
+  'value/context.hh',
+)
+
+this_library = library(
+  'nixexpr',
+  sources,
+  parser_tab,
+  lexer_tab,
+  generated_headers,
+  dependencies : deps_public + deps_private + deps_other,
+  install : true,
+)
+
+install_headers(headers, subdir : 'nix', preserve_path : true)
+
+requires = []
+foreach dep : deps_public_subproject
+  requires += dep.name()
+endforeach
+requires += deps_public
+
+import('pkgconfig').generate(
+  this_library,
+  filebase : meson.project_name(),
+  name : 'Nix',
+  description : 'Nix Package Manager',
+  subdirs : ['nix'],
+  extra_cflags : ['-std=c++2a'],
+  requires : requires,
+  requires_private : deps_private,
+  libraries_private : ['-lboost_container', '-lboost_context'],
+)
+
+meson.override_dependency(meson.project_name(), declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : this_library,
+  compile_args : ['-std=c++2a'],
+  dependencies : deps_public_subproject + deps_public,
+))

src/libexpr/meson.options

@@ -0,0 +1,3 @@
+option('gc', type : 'feature',
+  description : 'enable garbage collection in the Nix expression evaluator (requires Boehm GC)',
+)

src/libexpr/package.nix

@@ -0,0 +1,130 @@
+{ lib
+, stdenv
+, releaseTools
+
+, meson
+, ninja
+, pkg-config
+
+, nix-util
+, nix-store
+, nix-fetchers
+, boost
+, boehmgc
+, nlohmann_json
+
+# Configuration Options
+
+, versionSuffix ? ""
+
+# Check test coverage of Nix. Probably want to use with at least
+# one of `doCheck` or `doInstallCheck` enabled.
+, withCoverageChecks ? false
+
+# Whether to use garbage collection for the Nix language evaluator.
+#
+# If it is disabled, we just leak memory, but this is not as bad as it
+# sounds so long as evaluation just takes places within short-lived
+# processes. (When the process exits, the memory is reclaimed; it is
+# only leaked *within* the process.)
+#
+# Temporarily disabled on Windows because the `GC_throw_bad_alloc`
+# symbol is missing during linking.
+, enableGC ? !stdenv.hostPlatform.isWindows
+}:
+
+let
+  inherit (lib) fileset;
+
+  version = lib.fileContents ./.version + versionSuffix;
+
+  mkDerivation =
+    if withCoverageChecks
+    then
+      # TODO support `finalAttrs` args function in
+      # `releaseTools.coverageAnalysis`.
+      argsFun:
+         releaseTools.coverageAnalysis (let args = argsFun args; in args)
+    else stdenv.mkDerivation;
+in
+
+mkDerivation (finalAttrs: {
+  pname = "nix-expr";
+  inherit version;
+
+  src = fileset.toSource {
+    root = ./.;
+    fileset = fileset.unions [
+      ./meson.build
+      ./meson.options
+      (fileset.fileFilter (file: file.hasExt "cc") ./.)
+      (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    ];
+  };
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+  ];
+
+  buildInputs = [
+    boost
+  ];
+
+  propagatedBuildInputs = [
+    nix-util
+    nix-store
+    nix-fetchers
+    nlohmann_json
+  ] ++ lib.optional enableGC boehmgc;
+
+  disallowedReferences = [ boost ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix
+    ''
+      echo ${version} > .version
+    '';
+
+  mesonFlags = [
+    (lib.mesonFeature "gc" enableGC)
+  ];
+
+  env = {
+    # Needed for Meson to find Boost.
+    # https://github.com/NixOS/nixpkgs/issues/86131.
+    BOOST_INCLUDEDIR = "${lib.getDev boost}/include";
+    BOOST_LIBRARYDIR = "${lib.getLib boost}/lib";
+  } // lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  enableParallelBuilding = true;
+
+  postInstall =
+    # Remove absolute path to boost libs that ends up in `Libs.private`
+    # by default, and would clash with out `disallowedReferences`. Part
+    # of the https://github.com/NixOS/nixpkgs/issues/45462 workaround.
+    ''
+      sed -i "$out/lib/pkgconfig/nix-expr.pc" -e 's, ${lib.getLib boost}[^ ]*,,g'
+    '';
+
+  separateDebugInfo = !stdenv.hostPlatform.isStatic;
+
+  # TODO Always true after https://github.com/NixOS/nixpkgs/issues/318564
+  strictDeps = !withCoverageChecks;
+
+  hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+} // lib.optionalAttrs withCoverageChecks {
+  lcovFilter = [ "*/boost/*" "*-tab.*" ];
+
+  hardeningDisable = [ "fortify" ];
+})

src/libexpr/primops/fetchTree.cc

@@ -1,4 +1,4 @@
-#include "libfetchers/attrs.hh"
+#include "attrs.hh"
 #include "primops.hh"
 #include "eval-inline.hh"
 #include "eval-settings.hh"

src/libfetchers/meson.build

@@ -20,27 +20,24 @@ deps_private = [ ]
 # See note in ../nix-util/meson.build
 deps_public = [ ]
 
+# See note in ../nix-util/meson.build
+deps_public_subproject = [ ]
+
 # See note in ../nix-util/meson.build
 deps_other = [ ]
 
-configdata = configuration_data()
+foreach nix_dep : [
-
+  dependency('nix-util'),
-nix_util = dependency('nix-util')
+  dependency('nix-store'),
-if nix_util.type_name() == 'internal'
+]
-  # subproject sadly no good for pkg-config module
+  if nix_dep.type_name() == 'internal'
-  deps_other += nix_util
+    deps_public_subproject += nix_dep
-else
+    # subproject sadly no good for pkg-config module
-  deps_public += nix_util
+    deps_other += nix_dep
-endif
+  else
-
+    deps_public += nix_dep
-nix_store = dependency('nix-store')
+  endif
-if nix_store.type_name() == 'internal'
+endforeach
-  # subproject sadly no good for pkg-config module
-  deps_other += nix_store
-else
-  deps_public += nix_store
-endif
-
 
 nlohmann_json = dependency('nlohmann_json', version : '>= 3.9')
 deps_public += nlohmann_json
@@ -113,14 +110,9 @@ this_library = library(
 install_headers(headers, subdir : 'nix', preserve_path : true)
 
 requires = []
-if nix_util.type_name() == 'internal'
+foreach dep : deps_public_subproject
-  # `requires` cannot contain declared dependencies (from the
+  requires += dep.name()
-  # subproject), so we need to do this manually
+endforeach
-  requires += 'nix-util'
-endif
-if nix_store.type_name() == 'internal'
-  requires += 'nix-store'
-endif
 requires += deps_public
 
 import('pkgconfig').generate(
@@ -138,5 +130,5 @@ meson.override_dependency(meson.project_name(), declare_dependency(
   include_directories : include_directories('.'),
   link_with : this_library,
   compile_args : ['-std=c++2a'],
-  dependencies : [nix_util, nix_store],
+  dependencies : deps_public_subproject + deps_public,
 ))

src/libfetchers/package.nix

@@ -38,7 +38,7 @@ let
 in
 
 mkDerivation (finalAttrs: {
-  pname = "nix-fetchers";
+  pname = "nix-flake";
   inherit version;
 
   src = fileset.toSource {
@@ -80,11 +80,6 @@ mkDerivation (finalAttrs: {
 
   enableParallelBuilding = true;
 
-  postInstall =
-    # Remove absolute path to boost libs
-    ''
-    '';
-
   separateDebugInfo = !stdenv.hostPlatform.isStatic;
 
   # TODO `releaseTools.coverageAnalysis` in Nixpkgs needs to be updated

src/libflake/.version

@@ -0,0 +1 @@
+../../.version

src/libflake/meson.build

@@ -0,0 +1,120 @@
+project('nix-flake', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+# See note in ../nix-util/meson.build
+deps_private = [ ]
+
+# See note in ../nix-util/meson.build
+deps_public = [ ]
+
+# See note in ../nix-util/meson.build
+deps_public_subproject = [ ]
+
+# See note in ../nix-util/meson.build
+deps_other = [ ]
+
+foreach nix_dep : [
+  dependency('nix-util'),
+  dependency('nix-store'),
+  dependency('nix-fetchers'),
+  dependency('nix-expr'),
+]
+  if nix_dep.type_name() == 'internal'
+    deps_public_subproject += nix_dep
+    # subproject sadly no good for pkg-config module
+    deps_other += nix_dep
+  else
+    deps_public += nix_dep
+  endif
+endforeach
+
+nlohmann_json = dependency('nlohmann_json', version : '>= 3.9')
+deps_public += nlohmann_json
+
+libgit2 = dependency('libgit2')
+deps_public += libgit2
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.h',
+  '-include', 'config-store.h',
+  # '-include', 'config-fetchers.h',
+  '-include', 'config-expr.h',
+  '-Wno-deprecated-declarations',
+  '-Wimplicit-fallthrough',
+  '-Werror=switch',
+  '-Werror=switch-enum',
+  '-Wdeprecated-copy',
+  '-Wignored-qualifiers',
+  # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
+  # at ~1% overhead in `nix search`.
+  #
+  # FIXME: remove when we get meson 1.4.0 which will default this to on for us:
+  # https://mesonbuild.com/Release-notes-for-1-4-0.html#ndebug-setting-now-controls-c-stdlib-assertions
+  '-D_GLIBCXX_ASSERTIONS=1',
+  language : 'cpp',
+)
+
+sources = files(
+  'flake-settings.cc',
+  'flake/config.cc',
+  'flake/flake.cc',
+  'flake/flakeref.cc',
+  'flake/url-name.cc',
+  'flake/lockfile.cc',
+)
+
+headers = files(
+  'flake-settings.hh',
+  'flake/flake.hh',
+  'flake/flakeref.hh',
+  'flake/lockfile.hh',
+  'flake/url-name.hh',
+)
+
+this_library = library(
+  'nixflake',
+  sources,
+  dependencies : deps_public + deps_private + deps_other,
+  install : true,
+)
+
+install_headers(headers, subdir : 'nix', preserve_path : true)
+
+requires = []
+foreach dep : deps_public_subproject
+  requires += dep.name()
+endforeach
+requires += deps_public
+
+import('pkgconfig').generate(
+  this_library,
+  filebase : meson.project_name(),
+  name : 'Nix',
+  description : 'Nix Package Manager',
+  subdirs : ['nix'],
+  extra_cflags : ['-std=c++2a'],
+  requires : requires,
+  requires_private : deps_private,
+)
+
+meson.override_dependency(meson.project_name(), declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : this_library,
+  compile_args : ['-std=c++2a'],
+  dependencies : deps_public_subproject + deps_public,
+))

src/libflake/package.nix

@@ -0,0 +1,99 @@
+{ lib
+, stdenv
+, releaseTools
+
+, meson
+, ninja
+, pkg-config
+
+, nix-util
+, nix-store
+, nix-fetchers
+, nix-expr
+, nlohmann_json
+, libgit2
+, man
+
+# Configuration Options
+
+, versionSuffix ? ""
+
+# Check test coverage of Nix. Probably want to use with with at least
+# one of `doCheck` or `doInstallCheck` enabled.
+, withCoverageChecks ? false
+
+}:
+
+let
+  inherit (lib) fileset;
+
+  version = lib.fileContents ./.version + versionSuffix;
+
+  mkDerivation =
+    if withCoverageChecks
+    then
+      # TODO support `finalAttrs` args function in
+      # `releaseTools.coverageAnalysis`.
+      argsFun:
+         releaseTools.coverageAnalysis (let args = argsFun args; in args)
+    else stdenv.mkDerivation;
+in
+
+mkDerivation (finalAttrs: {
+  pname = "nix-flake";
+  inherit version;
+
+  src = fileset.toSource {
+    root = ./.;
+    fileset = fileset.unions [
+      ./meson.build
+      (fileset.fileFilter (file: file.hasExt "cc") ./.)
+      (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    ];
+  };
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+  ];
+
+  propagatedBuildInputs = [
+    nix-store
+    nix-util
+    nix-fetchers
+    nix-expr
+    nlohmann_json
+  ];
+
+  preConfigure =
+    # "Inline" .version so its not a symlink, and includes the suffix
+    ''
+      echo ${version} > .version
+    '';
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  enableParallelBuilding = true;
+
+  separateDebugInfo = !stdenv.hostPlatform.isStatic;
+
+  # TODO `releaseTools.coverageAnalysis` in Nixpkgs needs to be updated
+  # to work with `strictDeps`.
+  strictDeps = !withCoverageChecks;
+
+  hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+} // lib.optionalAttrs withCoverageChecks {
+  lcovFilter = [ "*-tab.*" ];
+
+  hardeningDisable = ["fortify"];
+})

src/libstore/meson.build

@@ -20,6 +20,9 @@ deps_private = [ ]
 # See note in ../nix-util/meson.build
 deps_public = [ ]
 
+# See note in ../nix-util/meson.build
+deps_public_subproject = [ ]
+
 # See note in ../nix-util/meson.build
 deps_other = [ ]
 
@@ -30,13 +33,17 @@ configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
 
 configdata.set_quoted('SYSTEM', host_machine.system())
 
-nix_util = dependency('nix-util')
+foreach nix_dep : [
-if nix_util.type_name() == 'internal'
+  dependency('nix-util'),
-  # subproject sadly no good for pkg-config module
+]
-  deps_other += nix_util
+  if nix_dep.type_name() == 'internal'
-else
+    deps_public_subproject += nix_dep
-  deps_public += nix_util
+    # subproject sadly no good for pkg-config module
-endif
+    deps_other += nix_dep
+  else
+    deps_public += nix_dep
+  endif
+endforeach
 
 run_command('ln', '-s',
   meson.project_build_root() / '__nothing_link_target',
@@ -122,13 +129,16 @@ if enable_embedded_sandbox_shell
 endif
 
 generated_headers = []
-foreach header : [ 'schema.sql', 'ca-specific-schema.sql' ]
+foreach header : [
+  'schema.sql',
+  'ca-specific-schema.sql',
+]
   generated_headers += custom_target(
     command : [ 'bash', '-c', '{ echo \'R"__NIX_STR(\' && cat @INPUT@ && echo \')__NIX_STR"\'; } > "$1"', '_ignored_argv0', '@OUTPUT@' ],
     input : header,
     output : '@PLAINNAME@.gen.hh',
     install : true,
-    install_dir : get_option('includedir') / 'nix'
+    install_dir : get_option('includedir') / 'nix',
   )
 endforeach
 
@@ -248,7 +258,7 @@ include_dirs = [
   include_directories('build'),
 ]
 
-headers = [config_h] +files(
+headers = [config_h] + files(
   'binary-cache-store.hh',
   'build-result.hh',
   'build/derivation-goal.hh',
@@ -427,11 +437,9 @@ this_library = library(
 install_headers(headers, subdir : 'nix', preserve_path : true)
 
 requires = []
-if nix_util.type_name() == 'internal'
+foreach dep : deps_public_subproject
-  # `requires` cannot contain declared dependencies (from the
+  requires += dep.name()
-  # subproject), so we need to do this manually
+endforeach
-  requires += 'nix-util'
-endif
 requires += deps_public
 
 import('pkgconfig').generate(
@@ -450,5 +458,5 @@ meson.override_dependency(meson.project_name(), declare_dependency(
   include_directories : include_dirs,
   link_with : this_library,
   compile_args : ['-std=c++2a'],
-  dependencies : [nix_util],
+  dependencies : deps_public_subproject + deps_public,
 ))

src/libstore/package.nix

@@ -23,9 +23,6 @@
 # Check test coverage of Nix. Probably want to use with at least
 # one of `doCheck` or `doInstallCheck` enabled.
 , withCoverageChecks ? false
-
-# Avoid setting things that would interfere with a functioning devShell
-, forDevShell ? false
 }:
 
 let

tests/unit/libutil-support/meson.build

@@ -20,9 +20,27 @@ deps_private = [ ]
 # See note in ../nix-util/meson.build
 deps_public = [ ]
 
+# See note in ../nix-util/meson.build
+deps_public_subproject = [ ]
+
 # See note in ../nix-util/meson.build
 deps_other = [ ]
 
+foreach nix_dep : [
+  dependency('nix-util'),
+]
+  if nix_dep.type_name() == 'internal'
+    deps_public_subproject += nix_dep
+    # subproject sadly no good for pkg-config module
+    deps_other += nix_dep
+  else
+    deps_public += nix_dep
+  endif
+endforeach
+
+rapidcheck = dependency('rapidcheck')
+deps_public += rapidcheck
+
 add_project_arguments(
   '-Wno-deprecated-declarations',
   '-Wimplicit-fallthrough',
@@ -66,17 +84,6 @@ else
   linker_export_flags = []
 endif
 
-nix_util = dependency('nix-util')
-if nix_util.type_name() == 'internal'
-  # subproject sadly no good for pkg-config module
-  deps_other += nix_util
-else
-  deps_public += nix_util
-endif
-
-rapidcheck = dependency('rapidcheck')
-deps_public += rapidcheck
-
 this_library = library(
   'nix-util-test-support',
   sources,
@@ -90,7 +97,11 @@ this_library = library(
 
 install_headers(headers, subdir : 'nix', preserve_path : true)
 
-libraries_private = []
+requires = []
+foreach dep : deps_public_subproject
+  requires += dep.name()
+endforeach
+requires += deps_public
 
 import('pkgconfig').generate(
   this_library,
@@ -99,7 +110,7 @@ import('pkgconfig').generate(
   description : 'Nix Package Manager',
   subdirs : ['nix'],
   extra_cflags : ['-std=c++2a'],
-  requires : deps_public,
+  requires : requires,
   requires_private : deps_private,
 )
 
@@ -107,5 +118,5 @@ meson.override_dependency(meson.project_name(), declare_dependency(
   include_directories : include_dirs,
   link_with : this_library,
   compile_args : ['-std=c++2a'],
-  dependencies : [],
+  dependencies : deps_public_subproject + deps_public,
 ))

tests/unit/libutil/meson.build

@@ -18,18 +18,57 @@ cxx = meson.get_compiler('cpp')
 deps_private = [ ]
 
 # See note in ../nix-util/meson.build
-deps_public = [ ]
+deps_private_subproject = [ ]
 
 # See note in ../nix-util/meson.build
 deps_other = [ ]
 
 configdata = configuration_data()
 
+# TODO rename, because it will conflict with downstream projects
+configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
+
+foreach nix_dep : [
+  dependency('nix-util'),
+  dependency('nix-util-c'),
+  dependency('nix-util-test-support'),
+]
+  if nix_dep.type_name() == 'internal'
+    deps_private_subproject += nix_dep
+    # subproject sadly no good for pkg-config module
+    deps_other += nix_dep
+  else
+    deps_private += nix_dep
+  endif
+endforeach
+
+if host_machine.system() == 'cygwin' or host_machine.system() == 'windows'
+  # Windows DLLs are stricter about symbol visibility than Unix shared
+  # objects --- see https://gcc.gnu.org/wiki/Visibility for details.
+  # This is a temporary sledgehammer to export everything like on Unix,
+  # and not detail with this yet.
+  #
+  # TODO do not do this, and instead do fine-grained export annotations.
+  linker_export_flags = ['-Wl,--export-all-symbols']
+else
+  linker_export_flags = []
+endif
+
+rapidcheck = dependency('rapidcheck')
+deps_private += rapidcheck
+
+gtest = dependency('gtest', main : true)
+deps_private += gtest
+
+config_h = configure_file(
+  configuration : configdata,
+  output : 'config-util-test.h',
+)
+
 add_project_arguments(
   # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
   # It would be nice for our headers to be idempotent instead.
   '-include', 'config-util-test.h',
-  # '-include', 'config-store.h',
   '-Wno-deprecated-declarations',
   '-Wimplicit-fallthrough',
   '-Werror=switch',
@@ -46,14 +85,6 @@ add_project_arguments(
   language : 'cpp',
 )
 
-# TODO rename, because it will conflict with downstream projects
-configdata.set_quoted('PACKAGE_VERSION', meson.project_version())
-
-config_h = configure_file(
-  configuration : configdata,
-  output : 'config-util-test.h',
-)
-
 sources = files(
   'args.cc',
   'canon-path.cc',
@@ -80,52 +111,11 @@ sources = files(
 
 include_dirs = [include_directories('.')]
 
-if host_machine.system() == 'cygwin' or host_machine.system() == 'windows'
-  # Windows DLLs are stricter about symbol visibility than Unix shared
-  # objects --- see https://gcc.gnu.org/wiki/Visibility for details.
-  # This is a temporary sledgehammer to export everything like on Unix,
-  # and not detail with this yet.
-  #
-  # TODO do not do this, and instead do fine-grained export annotations.
-  linker_export_flags = ['-Wl,--export-all-symbols']
-else
-  linker_export_flags = []
-endif
-
-nix_util = dependency('nix-util')
-if nix_util.type_name() == 'internal'
-  # subproject sadly no good for pkg-config module
-  deps_other += nix_util
-else
-  deps_public += nix_util
-endif
-
-nix_util_c = dependency('nix-util-c')
-if nix_util_c.type_name() == 'internal'
-  # subproject sadly no good for pkg-config module
-  deps_other += nix_util_c
-else
-  deps_public += nix_util_c
-endif
-
-nix_util_test_support = dependency('nix-util-test-support')
-if nix_util_test_support.type_name() == 'internal'
-  # subproject sadly no good for pkg-config module
-  deps_other += nix_util_test_support
-else
-  deps_public += nix_util_test_support
-endif
-
-rapidcheck = dependency('rapidcheck')
-deps_public += rapidcheck
-
-gtest = dependency('gtest', main : true)
-deps_public += gtest
 
 this_exe = executable(
   'nix-util-test',
   sources,
-  dependencies : deps_public + deps_private + deps_other,
+  dependencies : deps_private_subproject + deps_private + deps_other,
   include_directories : include_dirs,
   # TODO: -lrapidcheck, see ../libutil-support/build.meson
   link_args: linker_export_flags + ['-lrapidcheck'],
@@ -139,5 +129,4 @@ meson.override_dependency(meson.project_name(), declare_dependency(
   include_directories : include_dirs,
   link_with : this_exe,
   compile_args : ['-std=c++2a'],
-  dependencies : [],
 ))