fix(tui): detect Linux user bus socket

packages/tui/src/desktop-notify.ts

@@ -20,6 +20,8 @@
 // iTerm2, WezTerm, …) keep working unchanged and the BEL emission still fires
 // for tmux `monitor-bell`, X11 urgency hints, and audible-bell handlers.
 
+import * as fs from "node:fs";
+import * as path from "node:path";
 import { $which } from "@oh-my-pi/pi-utils";
 import type { TerminalId, TerminalNotification } from "./terminal-capabilities";
 
@@ -42,9 +44,12 @@ export interface DesktopNotifier {
 export function hasLinuxDesktopSession(
 	platform: NodeJS.Platform = process.platform,
 	env: NodeJS.ProcessEnv = Bun.env,
+	fileExists: (path: string) => boolean = fs.existsSync,
 ): boolean {
 	if (platform !== "linux") return false;
-	return Boolean(env.DBUS_SESSION_BUS_ADDRESS);
+	if (env.DBUS_SESSION_BUS_ADDRESS) return true;
+	const runtimeDir = env.XDG_RUNTIME_DIR;
+	return Boolean(runtimeDir && fileExists(path.join(runtimeDir, "bus")));
 }
 
 /**

packages/tui/test/desktop-notify.test.ts

@@ -19,6 +19,14 @@ describe("hasLinuxDesktopSession", () => {
 		expect(hasLinuxDesktopSession("darwin", LINUX_ENV)).toBe(false);
 		expect(hasLinuxDesktopSession("win32", LINUX_ENV)).toBe(false);
 	});
+
+	it("accepts the systemd user bus socket when the address is not exported", () => {
+		const env = { XDG_RUNTIME_DIR: "/run/user/1000" };
+		const fileExists = (path: string) => path === "/run/user/1000/bus";
+
+		expect(hasLinuxDesktopSession("linux", env, fileExists)).toBe(true);
+		expect(hasLinuxDesktopSession("linux", env, () => false)).toBe(false);
+	});
 });
 
 describe("shouldDeliverDesktopNotification", () => {