fresh-editor: add opt-in mutable settings

modules/misc/news/2026/10/2026-10-21_06-43-34.nix

@@ -0,0 +1,11 @@
+{ config, ... }:
+{
+  time = "2026-10-21T06:43:34+00:00";
+  condition = config.programs.fresh-editor.enable;
+  message = ''
+    Fresh now supports `programs.fresh-editor.mutableSettings` to load
+    declarative settings from `config_linux.json` or `config_macos.json`,
+    leaving `config.json` writable by Fresh. Declarative settings override
+    the same keys in the user file. The option is disabled by default.
+  '';
+}

modules/programs/fresh-editor.nix

@@ -16,12 +16,38 @@ let
 
   cfg = config.programs.fresh-editor;
   jsonFormat = pkgs.formats.json { };
+  settingsFile =
+    if cfg.mutableSettings then
+      "config_${if pkgs.stdenv.hostPlatform.isDarwin then "macos" else "linux"}.json"
+    else
+      "config.json";
 in
 {
   meta.maintainers = with lib.maintainers; [ drupol ];
   options.programs.fresh-editor = {
     enable = mkEnableOption "fresh-editor";
     package = mkPackageOption pkgs "fresh-editor" { nullable = true; };
+    mutableSettings = mkOption {
+      type = types.bool;
+      default = false;
+      example = true;
+      description = ''
+        Whether to put declarative settings in Fresh's platform configuration
+        file, leaving {file}`fresh/config.json` writable by Fresh. Declarative
+        settings override the same keys in the user file. Project and session
+        settings take precedence over the declarative settings.
+
+        The declarative file is
+        {file}`$XDG_CONFIG_HOME/fresh/config_linux.json` on Linux and
+        {file}`~/.config/fresh/config_macos.json` on macOS. Fresh ignores
+        {env}`XDG_CONFIG_HOME` on macOS.
+
+        Before disabling this option while
+        {option}`programs.fresh-editor.settings` is non-empty, remove or back up
+        the Fresh-owned {file}`fresh/config.json`. Home Manager otherwise
+        treats it as a file collision.
+      '';
+    };
     extraPackages = mkOption {
       type = with types; listOf package;
       default = [ ];
@@ -78,7 +104,11 @@ in
       VISUAL = "fresh";
     };
 
-    xdg.configFile."fresh/config.json" = mkIf (cfg.settings != { }) {
+    xdg.configFile."fresh/${settingsFile}" = mkIf (cfg.settings != { }) {
+      # Fresh uses ~/.config on macOS even when XDG_CONFIG_HOME is set.
+      target = mkIf (
+        cfg.mutableSettings && pkgs.stdenv.hostPlatform.isDarwin
+      ) "${config.home.homeDirectory}/.config/fresh/${settingsFile}";
       source = jsonFormat.generate "config.json" cfg.settings;
     };
   };

tests/darwinScrublist.nix

@@ -61,6 +61,7 @@ let
     "feh"
     "flameshot"
     "freetube"
+    "fresh-editor"
     "fzf"
     "gallery-dl"
     "getconf"

tests/modules/programs/fresh-editor/default.nix

@@ -1,3 +1,8 @@
 {
   fresh-editor = ./fresh-editor-settings.nix;
+  fresh-editor-mutable = import ./mutable-settings.nix "mutable";
+  fresh-editor-mutable-custom-xdg = import ./mutable-settings.nix "custom-xdg";
+  fresh-editor-mutable-disabled = import ./mutable-settings.nix "disabled";
+  fresh-editor-mutable-empty = import ./mutable-settings.nix "empty";
+  fresh-editor-immutable-empty = import ./mutable-settings.nix "immutable-empty";
 }

tests/modules/programs/fresh-editor/fresh-editor-settings.nix

@@ -6,5 +6,7 @@
 
   nmt.script = ''
     assertFileContent home-files/.config/fresh/config.json ${./config.json}
+    assertPathNotExists home-files/.config/fresh/config_linux.json
+    assertPathNotExists home-files/.config/fresh/config_macos.json
   '';
 }

tests/modules/programs/fresh-editor/mutable-settings.nix

@@ -0,0 +1,52 @@
+mode:
+
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  customXdg = mode == "custom-xdg";
+  hasSettings =
+    !(lib.elem mode [
+      "empty"
+      "immutable-empty"
+    ]);
+  configDir =
+    if customXdg && !pkgs.stdenv.hostPlatform.isDarwin then "config with spaces" else ".config";
+  platformFile =
+    if pkgs.stdenv.hostPlatform.isDarwin then "config_macos.json" else "config_linux.json";
+  otherPlatformFile =
+    if pkgs.stdenv.hostPlatform.isDarwin then "config_linux.json" else "config_macos.json";
+in
+{
+  xdg.configHome = lib.mkIf customXdg "${config.home.homeDirectory}/config with spaces";
+
+  programs.fresh-editor = {
+    enable = mode != "disabled";
+    mutableSettings = mode != "immutable-empty";
+    settings = lib.optionalAttrs hasSettings (builtins.fromJSON (builtins.readFile ./config.json));
+  };
+
+  nmt.script = ''
+    assertPathNotExists "home-files/${configDir}/fresh/config.json"
+    assertPathNotExists "home-files/${configDir}/fresh/${otherPlatformFile}"
+  ''
+  + (
+    if hasSettings && mode != "disabled" then
+      ''
+        assertFileContent "home-files/${configDir}/fresh/${platformFile}" ${./config.json}
+      ''
+    else
+      ''
+        assertPathNotExists "home-files/${configDir}/fresh/${platformFile}"
+      ''
+  )
+  + lib.optionalString customXdg ''
+    assertPathNotExists "home-files/${
+      if pkgs.stdenv.hostPlatform.isDarwin then "config with spaces" else ".config"
+    }/fresh"
+  '';
+}