fix(zed): support preexisting JSON5 settings (#7317)

Zed uses JSON5 for settings files. JQ doesn't understand that format and
fails if found, when merging with preexisting settings.

Here I add a conversion step that converts JSON5 to JSON before handling
the contents to JQ.

Besides, I changed the arguments in the jq function, so instead of using
`[0]` and `[1]`, we now use `$dynamic` and `$static` respectively. This
should make scripts more readable.

Fixes https://github.com/nix-community/home-manager/issues/7247
Fixes https://github.com/nix-community/home-manager/issues/7226

modules/programs/zed-editor.nix

@@ -15,13 +15,16 @@ let
 
   cfg = config.programs.zed-editor;
   jsonFormat = pkgs.formats.json { };
+  json5 = pkgs.python3Packages.toPythonApplication pkgs.python3Packages.json5;
   impureConfigMerger = empty: jqOperation: path: staticSettings: ''
     mkdir -p $(dirname ${lib.escapeShellArg path})
     if [ ! -e ${lib.escapeShellArg path} ]; then
       # No file? Create it
       echo ${lib.escapeShellArg empty} > ${lib.escapeShellArg path}
     fi
-    config="$(${pkgs.jq}/bin/jq -s ${lib.escapeShellArg jqOperation} ${lib.escapeShellArg path} ${lib.escapeShellArg staticSettings})"
+    dynamic="$(${lib.getExe json5} --as-json ${lib.escapeShellArg path})"
+    static="$(cat ${lib.escapeShellArg staticSettings})"
+    config="$(${lib.getExe pkgs.jq} -s ${lib.escapeShellArg jqOperation} --argjson dynamic "$dynamic" --argjson static "$static")"
     printf '%s\n' "$config" > ${lib.escapeShellArg path}
     unset config
   '';
@@ -170,7 +173,7 @@ in
     home.activation = mkMerge [
       (mkIf (mergedSettings != { }) {
         zedSettingsActivation = lib.hm.dag.entryAfter [ "linkGeneration" ] (
-          impureConfigMerger "{}" ".[0] * .[1]" "${config.xdg.configHome}/zed/settings.json" (
+          impureConfigMerger "{}" "$dynamic * $static" "${config.xdg.configHome}/zed/settings.json" (
             jsonFormat.generate "zed-user-settings" mergedSettings
           )
         );
@@ -178,7 +181,7 @@ in
       (mkIf (cfg.userKeymaps != [ ]) {
         zedKeymapActivation = lib.hm.dag.entryAfter [ "linkGeneration" ] (
           impureConfigMerger "[]"
-            ".[0] + .[1] | group_by(.context) | map(reduce .[] as $item ({}; . * $item))"
+            "$dynamic + $static | group_by(.context) | map(reduce .[] as $item ({}; . * $item))"
             "${config.xdg.configHome}/zed/keymap.json"
             (jsonFormat.generate "zed-user-keymaps" cfg.userKeymaps)
         );

tests/modules/programs/zed-editor/keymap.nix

@@ -30,6 +30,7 @@
     let
       preexistingKeymaps = builtins.toFile "preexisting.json" ''
         [
+          // Things changed interactively
           {
             "bindings": {
               "down": "menu::SelectNext"
@@ -41,12 +42,14 @@
             },
             "context": "Terminal"
           },
+
+          /* Manually changed */
           {
             "bindings": {
               "enter": "newline"
             },
-            "context": "Editor"
-          }
+            "context": "Editor",
+          },
         ]
       '';
 

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

@@ -27,7 +27,10 @@
     let
       preexistingSettings = builtins.toFile "preexisting.json" ''
         {
+          // I chose this theme interactively
           "theme": "Default",
+
+          /* I change AI settings interactively */
           "features": {
             "copilot": true,
             "ai_assist": true