treewide: remove Perl-based switch-to-configuration (#414882)

<!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->

- The Perl implementation of the `switch-to-configuration` program is removed. All switchable systems now use the Rust rewrite. Any prior usage of `system.switch.enableNg` must now be removed. If you have any outstanding issues with the new implementation, please open an issue on GitHub.

- The `services.polipo` module has been removed as `polipo` is unmaintained and archived upstream.

- The Pocket ID module ([`services.pocket-id`][#opt-services.pocket-id.enable]) and package (`pocket-id`) has been updated to 1.0.0. Some environment variables have been changed or removed, see the [migration guide](https://pocket-id.org/docs/setup/migrate-to-v1/).

      description = ''

        A program that writes a bootloader installation script to the path passed in the first command line argument.

        See `nixos/modules/system/activation/switch-to-configuration.pl`.

        See `pkgs/by-name/sw/switch-to-configuration-ng/src/src/main.rs`.

      '';

      type = types.unique {

        message = ''

  ...

}:

let

  perlWrapped = pkgs.perl.withPackages (

    p: with p; [

      ConfigIniFiles

      FileSlurp

    ]

  );

in

{

  options.system.switch = {

    enable = lib.mkOption {

  imports = [

    (lib.mkRemovedOptionModule [ "system" "switch" "enableNg" ] ''

      This option controlled the usage of the new switch-to-configuration-ng,

      which is now the only switch-to-configuration implementation. This option

      can be removed from configuration. If there are outstanding issues

      preventing you from using the new implementation, please open an issue on

      GitHub.

    '')

  ];

  options.system.switch.enable = lib.mkOption {

    type = lib.types.bool;

    default = true;

    description = ''

    '';

  };

    enableNg = lib.mkOption {

      type = lib.types.bool;

      default = config.system.switch.enable;

      defaultText = lib.literalExpression "config.system.switch.enable";

      description = ''

        Whether to use `switch-to-configuration-ng`, the Rust-based

        re-implementation of the original Perl `switch-to-configuration`.

      '';

    };

  };

  config = lib.mkMerge [

    (lib.mkIf (config.system.switch.enable && !config.system.switch.enableNg) {

      warnings = [

        ''

          The Perl implementation of switch-to-configuration will be deprecated

          and removed in the 25.05 release of NixOS. Please migrate to the

          newer implementation by removing `system.switch.enableNg = false`

          from your configuration. If you are unable to migrate due to any

          issues with the new implementation, please create an issue and tag

          the maintainers of `switch-to-configuration-ng`.

        ''

      ];

      system.activatableSystemBuilderCommands = ''

        mkdir $out/bin

        substitute ${./switch-to-configuration.pl} $out/bin/switch-to-configuration \

          --subst-var out \

          --subst-var-by toplevel ''${!toplevelVar} \

          --subst-var-by coreutils "${pkgs.coreutils}" \

          --subst-var-by distroId ${lib.escapeShellArg config.system.nixos.distroId} \

          --subst-var-by installBootLoader ${lib.escapeShellArg config.system.build.installBootLoader} \

          --subst-var-by preSwitchCheck ${lib.escapeShellArg config.system.preSwitchChecksScript} \

          --subst-var-by localeArchive "${config.i18n.glibcLocales}/lib/locale/locale-archive" \

          --subst-var-by perl "${perlWrapped}" \

          --subst-var-by shell "${pkgs.bash}/bin/sh" \

          --subst-var-by su "${pkgs.shadow.su}/bin/su" \

          --subst-var-by systemd "${config.systemd.package}" \

          --subst-var-by utillinux "${pkgs.util-linux}" \

          ;

        chmod +x $out/bin/switch-to-configuration

        ${lib.optionalString (pkgs.stdenv.hostPlatform == pkgs.stdenv.buildPlatform) ''

          if ! output=$(${perlWrapped}/bin/perl -c $out/bin/switch-to-configuration 2>&1); then

            echo "switch-to-configuration syntax is not valid:"

            echo "$output"

            exit 1

          fi

        ''}

      '';

    })

    (lib.mkIf config.system.switch.enableNg {

  config = lib.mkIf config.system.switch.enable {

    # Use a subshell so we can source makeWrapper's setup hook without

    # affecting the rest of activatableSystemBuilderCommands.

    system.activatableSystemBuilderCommands = ''

          --set SYSTEMD ${config.systemd.package}

      )

    '';

    })

  ];

  };

}

  swapspace = handleTestOn [ "aarch64-linux" "x86_64-linux" ] ./swapspace.nix { };

  sway = runTest ./sway.nix;

  swayfx = runTest ./swayfx.nix;

  switchTest = runTest {

    imports = [ ./switch-test.nix ];

    defaults.system.switch.enableNg = false;

  };

  switchTestNg = runTest {

    imports = [ ./switch-test.nix ];

    defaults.system.switch.enableNg = true;

  };

  switchTest = runTest ./switch-test.nix;

  sx = runTest ./sx.nix;

  sympa = runTest ./sympa.nix;

  syncthing = runTest ./syncthing.nix;