nix/packaging/dev-shell.nix

{
  lib,
  devFlake,
}:

{ pkgs }:

pkgs.nixComponents2.nix-util.overrideAttrs (
  attrs:

  let
    stdenv = pkgs.nixDependencies2.stdenv;
    buildCanExecuteHost = stdenv.buildPlatform.canExecute stdenv.hostPlatform;
    modular = devFlake.getSystem stdenv.buildPlatform.system;
    transformFlag =
      prefix: flag:
      assert builtins.isString flag;
      let
        rest = builtins.substring 2 (builtins.stringLength flag) flag;
      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;

    # Remove the version suffix to avoid unnecessary attempts to substitute in nix develop
    version = lib.fileContents ../.version;
    name = attrs.pname;

    installFlags = "sysconfdir=$(out)/etc";
    shellHook = ''
      PATH=$prefix/bin:$PATH
      unset PYTHONPATH
      export MANPATH=$out/share/man:$MANPATH

      # Make bash completion work.
      XDG_DATA_DIRS+=:$out/share

      # Make the default phases do the right thing.
      # FIXME: this wouldn't be needed if the ninja package set buildPhase() instead of $buildPhase.
      # FIXME: mesonConfigurePhase shouldn't cd to the build directory. It would be better to pass '-C <dir>' to ninja.

      cdToBuildDir() {
          if [[ ! -e build.ninja ]]; then
              cd build
          fi
      }

      configurePhase() {
          mesonConfigurePhase
      }

      buildPhase() {
          cdToBuildDir
          ninjaBuildPhase
      }

      checkPhase() {
          cdToBuildDir
          mesonCheckPhase
      }

      installPhase() {
          cdToBuildDir
          ninjaInstallPhase
      }
    '';

    # We use this shell with the local checkout, not unpackPhase.
    src = null;
    # Workaround https://sourceware.org/pipermail/gdb-patches/2025-October/221398.html
    # Remove when gdb fix is rolled out everywhere.
    separateDebugInfo = false;

    env = {
      # For `make format`, to work without installing pre-commit
      _NIX_PRE_COMMIT_HOOKS_CONFIG = "${(pkgs.formats.yaml { }).generate "pre-commit-config.yaml"
        modular.pre-commit.settings.rawConfig
      }";
    }
    // lib.optionalAttrs stdenv.hostPlatform.isLinux {
      CC_LD = "mold";
      CXX_LD = "mold";
    };

    mesonFlags =
      map (transformFlag "libutil") (ignoreCrossFile pkgs.nixComponents2.nix-util.mesonFlags)
      ++ map (transformFlag "libstore") (ignoreCrossFile pkgs.nixComponents2.nix-store.mesonFlags)
      ++ map (transformFlag "libfetchers") (ignoreCrossFile pkgs.nixComponents2.nix-fetchers.mesonFlags)
      ++ lib.optionals havePerl (
        map (transformFlag "perl") (ignoreCrossFile pkgs.nixComponents2.nix-perl-bindings.mesonFlags)
      )
      ++ map (transformFlag "libexpr") (ignoreCrossFile pkgs.nixComponents2.nix-expr.mesonFlags)
      ++ map (transformFlag "libcmd") (ignoreCrossFile pkgs.nixComponents2.nix-cmd.mesonFlags);

    nativeBuildInputs =
      let
        inputs =
          attrs.nativeBuildInputs or [ ]
          ++ pkgs.nixComponents2.nix-util.nativeBuildInputs
          ++ pkgs.nixComponents2.nix-store.nativeBuildInputs
          ++ pkgs.nixComponents2.nix-fetchers.nativeBuildInputs
          ++ pkgs.nixComponents2.nix-expr.nativeBuildInputs
          ++ lib.optionals havePerl pkgs.nixComponents2.nix-perl-bindings.nativeBuildInputs
          ++ lib.optionals buildCanExecuteHost pkgs.nixComponents2.nix-manual.externalNativeBuildInputs
          ++ pkgs.nixComponents2.nix-internal-api-docs.nativeBuildInputs
          ++ pkgs.nixComponents2.nix-external-api-docs.nativeBuildInputs
          ++ pkgs.nixComponents2.nix-functional-tests.externalNativeBuildInputs
          ++ lib.optional (
            !buildCanExecuteHost
            # 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.gnused
            pkgs.buildPackages.shellcheck
            pkgs.buildPackages.changelog-d
            modular.pre-commit.settings.package
            (pkgs.writeScriptBin "pre-commit-hooks-install" modular.pre-commit.settings.installationScript)
            pkgs.buildPackages.nixfmt-rfc-style
            pkgs.buildPackages.shellcheck
            pkgs.buildPackages.gdb
          ]
          ++ lib.optional (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform) (
            lib.hiPrio pkgs.buildPackages.clang-tools
          )
          ++ lib.optional stdenv.hostPlatform.isLinux pkgs.buildPackages.mold-wrapped;
      in
      # FIXME: separateDebugInfo = false doesn't actually prevent -Wa,--compress-debug-sections
      # from making its way into NIX_CFLAGS_COMPILE.
      lib.filter (p: !lib.hasInfix "separate-debug-info" p) inputs;

    buildInputs = [
      pkgs.gbenchmark
    ]
    ++ attrs.buildInputs or [ ]
    ++ pkgs.nixComponents2.nix-util.buildInputs
    ++ pkgs.nixComponents2.nix-store.buildInputs
    ++ pkgs.nixComponents2.nix-store-tests.externalBuildInputs
    ++ pkgs.nixComponents2.nix-fetchers.buildInputs
    ++ pkgs.nixComponents2.nix-expr.buildInputs
    ++ pkgs.nixComponents2.nix-expr.externalPropagatedBuildInputs
    ++ pkgs.nixComponents2.nix-cmd.buildInputs
    ++ lib.optionals havePerl pkgs.nixComponents2.nix-perl-bindings.externalBuildInputs
    ++ lib.optional havePerl pkgs.perl;
  }
)