feat(wrapperModules.ghostty): init

Writes settings to a Nix store config file and loads it via
--config-default-files=false --config-file=<path>, isolating the wrapper
from the host config in both installed and ephemeral use. The host config
path varies by platform: ~/.config/ghostty/config on Linux, and
~/Library/Application Support/com.mitchellh.ghostty/config on macOS.

Ghostty +actions and --help use minimal option parsers that reject unknown
flags and exit silently, so argv0type bypasses flag injection for these.
+show-config and +validate-config are subject to the same parser limitation
and will show the host config rather than the generated one.

On macOS, ghostty-bin is used by default (the pre-built binary distribution
recommended for nix-darwin by the Ghostty installation docs).

Author: TrustworthyAdult

maintainers/default.nix

@@ -111,4 +111,9 @@
     github = "allen-liaoo";
     githubId = 16383622;
   };
+  trustworthyadult = {
+    name = "Michael Ross";
+    github = "TrustworthyAdult";
+    githubId = 104172948;
+  };
 }

wrapperModules/g/ghostty/check.nix

@@ -0,0 +1,39 @@
+{
+  pkgs,
+  self,
+  tlib,
+  ...
+}:
+let
+  inherit (tlib) isFile fileContains test;
+  wrapper = self.wrappers.ghostty.wrap {
+    inherit pkgs;
+    settings = {
+      font-size = 14;
+      theme = "catppuccin-mocha";
+      window-decoration = false;
+    };
+  };
+  configFile = "${wrapper}/ghostty-config";
+in
+test { wrapper = "ghostty"; } {
+  "ghostty wrapper binary should exist" = [ (isFile "${wrapper}/bin/ghostty") ];
+
+  "ghostty wrapper should disable default config and point to generated file" = [
+    (fileContains "${wrapper}/bin/ghostty" "--config-default-files=false")
+    (fileContains "${wrapper}/bin/ghostty" "--config-file=")
+  ];
+
+  "ghostty wrapper should bypass config flags for +actions and --help" = [
+    (fileContains "${wrapper}/bin/ghostty" "_ghostty_arg")
+    (fileContains "${wrapper}/bin/ghostty" "--help")
+  ];
+
+  "ghostty config file should exist" = [ (isFile configFile) ];
+
+  "ghostty settings should appear in generated config" = [
+    (fileContains configFile "font-size = 14")
+    (fileContains configFile "theme = catppuccin-mocha")
+    (fileContains configFile "window-decoration = false")
+  ];
+}

wrapperModules/g/ghostty/module.nix

@@ -0,0 +1,102 @@
+{
+  config,
+  wlib,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  toGhosttyConf = lib.generators.toKeyValue {
+    mkKeyValue = lib.generators.mkKeyValueDefault {
+      mkValueString = v: if builtins.isBool v then lib.boolToString v else toString v;
+    } " = ";
+  };
+in
+{
+  imports = [ wlib.modules.default ];
+
+  options.settings = lib.mkOption {
+    type = lib.types.attrsOf (
+      lib.types.oneOf [
+        lib.types.bool
+        lib.types.float
+        lib.types.int
+        lib.types.str
+      ]
+    );
+    default = { };
+    example = lib.literalExpression ''
+      {
+        font-size = 14;
+        theme = "catppuccin-mocha";
+        window-decoration = false;
+      }
+    '';
+    description = ''
+      Ghostty configuration written to a generated config file. The wrapper
+      passes {option}`--config-default-files=false` and
+      {option}`--config-file=<generated>`, so the host config is never loaded
+      -- including when the wrapper is used ephemerally on a machine that has
+      its own Ghostty config. The host config path varies by platform:
+      {file}`~/.config/ghostty/config` on Linux, and
+      {file}`~/Library/Application Support/com.mitchellh.ghostty/config` on
+      macOS.
+      See <https://ghostty.org/docs/config/reference> for all available options.
+
+      Note: if you pass an additional {option}`--config-file` flag at runtime,
+      Ghostty will merge it on top of the generated config (later files take
+      precedence for conflicting keys).
+
+      Note: {command}`ghostty +show-config` and {command}`ghostty
+      +validate-config` bypass the generated config entirely (their option
+      parsers reject {option}`--config-file`), so they will show the host
+      config if one exists -- this affects both installed and ephemeral use.
+
+      On macOS, `ghostty-bin` is used by default, which is the pre-built
+      binary distribution [recommended for nix-darwin](https://ghostty.org/docs/install/binary)
+      by the Ghostty installation docs.
+    '';
+  };
+
+  config = {
+    package = lib.mkDefault (if pkgs.stdenv.isDarwin then pkgs.ghostty-bin else pkgs.ghostty);
+    constructFiles.ghosttyConfig = {
+      content = toGhosttyConf config.settings;
+      relPath = "${config.binName}-config";
+    };
+    addFlag = [
+      "--config-default-files=false"
+      "--config-file=${config.constructFiles.ghosttyConfig.path}"
+    ];
+    # Ghostty has no environment variable for specifying a config file, so CLI
+    # flags are the only option: --config-default-files=false prevents loading
+    # the host's ~/.config/ghostty/config (including on machines where one
+    # exists), and --config-file points at the generated one.
+    #
+    # However, Ghostty +actions and --help have their own minimal Options
+    # struct with no _diagnostics field.  Any flag unrecognised by the action
+    # parser causes error.InvalidField and a silent exit with no output.
+    # argv0type detects these and execs Ghostty directly without injecting any
+    # flags.
+    #
+    # Consequence: +show-config and +validate-config will show the host's
+    # ~/.config/ghostty/config if present, not the generated config, because
+    # their option parsers also reject --config-file.  This applies equally to
+    # installed and ephemeral use.
+    argv0type =
+      let
+        binPath = lib.escapeShellArg config.wrapperPaths.input;
+      in
+      cmd: ''
+        for _ghostty_arg in "$@"; do
+          case "$_ghostty_arg" in
+            +*|--help) exec -a "$0" ${binPath} "$@";;
+          esac
+        done
+        exec -a "$0" ${cmd}
+      '';
+    meta.description = "Ghostty terminal emulator";
+    meta.maintainers = [ wlib.maintainers.trustworthyadult ];
+    meta.platforms = lib.platforms.linux ++ [ "x86_64-darwin" "aarch64-darwin" ];
+  };
+}