fix(nix): restore desktop app icon matching (#2506)

* fix(nix): identify desktop app for icon matching

* fix(desktop): ignore wrapper class in CLI passthrough

* fix(nix): give the Electron launcher a real app root

The Wayland app_id — what a bar or taskbar uses to find the .desktop
entry, and therefore the icon — is fixed during Electron startup, so
neither `--class=` nor main.ts's `app.setName()` reaches it on current
Electron. Launching `electron path/to/main.js` gives Electron no
package.json to read a name from, so the window published the default
"electron" app_id and shells drew the generic Electron icon.

Launch a one-file app root named "paseo-desktop" instead, matching the
installed desktop entry and hicolor icon. Older Electron (38) derives
the app_id from the runtime app name "Paseo", so also ship a NoDisplay
alias entry under that name; the icon resolves either way and the
launcher list still shows a single Paseo.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

nix/desktop-package.nix

@@ -187,11 +187,22 @@ buildNpmPackage {
       install -Dm644 packages/desktop/assets/icon.png \
         $out/share/icons/hicolor/512x512/apps/paseo-desktop.png
 
+      # Electron derives Wayland's toplevel app_id from the package name in the
+      # app root it launches. Point it at a one-file app named "paseo-desktop"
+      # so shells can match the window to the desktop entry and hicolor icon.
+      mkdir -p $out/share/paseo-desktop/electron-app
+      printf '%s\n' "{ \"name\": \"paseo-desktop\", \"version\": \"$version\", \"main\": \"index.js\" }" \
+        > $out/share/paseo-desktop/electron-app/package.json
+      printf '%s\n' 'require("../packages/desktop/dist/main.js");' \
+        > $out/share/paseo-desktop/electron-app/index.js
+
       # Chromium's setuid sandbox cannot live in the immutable Nix store.
       makeWrapper ${electron}/bin/electron $out/bin/paseo-desktop \
-        --add-flags "$out/share/paseo-desktop/packages/desktop/dist/main.js" \
+        --add-flags "$out/share/paseo-desktop/electron-app" \
         --add-flags "--no-sandbox" \
-        --set EXPO_DEV_URL "paseo://app/"
+        --add-flags "--class=paseo-desktop" \
+        --set EXPO_DEV_URL "paseo://app/" \
+        --set CHROME_DESKTOP "paseo-desktop.desktop"
 
       copyDesktopItems
     ''}
@@ -219,7 +230,23 @@ buildNpmPackage {
       exec = "paseo-desktop";
       icon = "paseo-desktop";
       categories = ["Development"];
+      startupWMClass = "paseo-desktop";
+    })
+    # Hidden alias entry. Which of the two names Electron ends up publishing as
+    # the Wayland app_id depends on the Electron version: 41 uses the app-root
+    # package.json `name` ("paseo-desktop"), 38 uses the runtime app name that
+    # main.ts sets ("Paseo"). Ship a NoDisplay entry for the second spelling so
+    # the icon resolves either way without a duplicate launcher item.
+    (makeDesktopItem {
+      name = "Paseo";
+      desktopName = "Paseo";
+      genericName = "AI Coding Agents";
+      comment = "Self-hosted daemon for AI coding agents";
+      exec = "paseo-desktop";
+      icon = "paseo-desktop";
+      categories = [ "Development" ];
       startupWMClass = "Paseo";
+      noDisplay = true;
     })
   ];
 

packages/desktop/src/daemon/cli/passthrough.test.ts

@@ -65,6 +65,23 @@ describe("passthrough CLI", () => {
     ).toBeNull();
   });
 
+  it("ignores Linux desktop identity arguments injected by the Nix wrapper", () => {
+    expect(
+      parsePassthroughCliArgs({
+        argv: [
+          "/nix/store/electron/bin/electron",
+          "/nix/store/paseo-desktop/share/paseo-desktop/electron-app",
+          "--no-sandbox",
+          "--class=paseo-desktop",
+          "daemon",
+          "status",
+        ],
+        isDefaultApp: true,
+        forceCli: false,
+      }),
+    ).toEqual(["daemon", "status"]);
+  });
+
   it("ignores Electron remote debugging switches", () => {
     expect(
       parsePassthroughCliArgs({

packages/desktop/src/daemon/cli/passthrough.ts

@@ -2,7 +2,7 @@ import { pathToFileURL } from "node:url";
 import { resolvePassthroughCliEntrypoint } from "./entrypoints.js";
 
 const DESKTOP_CLI_ENV = "PASEO_DESKTOP_CLI";
-const IGNORED_ARG_PREFIXES = ["-psn_", "--no-sandbox", "--remote-debugging-port="];
+const IGNORED_ARG_PREFIXES = ["-psn_", "--class=", "--no-sandbox", "--remote-debugging-port="];
 
 export type PassthroughCliRunner = (argv: string[]) => Promise<number>;