feat(coding-agent): print resume hint on interactive exit

packages/coding-agent/test/suite/regressions/5080-signal-shutdown-extension-cleanup.test.ts

@@ -1,4 +1,10 @@
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import chalk from "chalk";
 import { afterEach, describe, expect, test, vi } from "vitest";
+import { APP_NAME } from "../../../src/config.ts";
+import type { SessionManager } from "../../../src/core/session-manager.ts";
 import { InteractiveMode } from "../../../src/modes/interactive/interactive-mode.ts";
 
 // Regression for https://github.com/earendil-works/pi/issues/5080
@@ -16,6 +22,7 @@ type ShutdownThis = {
 	runtimeHost: { dispose: () => Promise<void> };
 	ui: { terminal: { drainInput: (ms: number) => Promise<void> } };
 	stop: () => void;
+	sessionManager: SessionManager;
 };
 
 type InteractiveModePrototypeWithShutdown = {
@@ -23,10 +30,42 @@ type InteractiveModePrototypeWithShutdown = {
 };
 
 const interactiveModePrototype = InteractiveMode.prototype as unknown;
+const tempDirs: string[] = [];
+const originalStdoutIsTTY = Object.getOwnPropertyDescriptor(process.stdout, "isTTY");
 
 class ProcessExitError extends Error {}
 
-function createContext(order: string[]): ShutdownThis {
+function createSessionManager(options: { sessionFile?: string } = {}): SessionManager {
+	return {
+		isPersisted: () => options.sessionFile !== undefined,
+		getSessionFile: () => options.sessionFile,
+		getSessionId: () => "test-session",
+		getSessionDir: () => "/tmp/pi-sessions",
+		usesDefaultSessionDir: () => true,
+	} as unknown as SessionManager;
+}
+
+function createTempFile(): string {
+	const dir = mkdtempSync(join(tmpdir(), "pi-shutdown-resume-hint-"));
+	tempDirs.push(dir);
+	const file = join(dir, "session.jsonl");
+	writeFileSync(file, "\n");
+	return file;
+}
+
+function setStdoutIsTTY(value: boolean): void {
+	Object.defineProperty(process.stdout, "isTTY", { configurable: true, value });
+}
+
+function restoreStdoutIsTTY(): void {
+	if (originalStdoutIsTTY) {
+		Object.defineProperty(process.stdout, "isTTY", originalStdoutIsTTY);
+	} else {
+		Reflect.deleteProperty(process.stdout, "isTTY");
+	}
+}
+
+function createContext(order: string[], sessionManager = createSessionManager()): ShutdownThis {
 	return {
 		isShuttingDown: false,
 		unregisterSignalHandlers: vi.fn(),
@@ -45,6 +84,7 @@ function createContext(order: string[]): ShutdownThis {
 		stop: vi.fn(() => {
 			order.push("stop");
 		}),
+		sessionManager,
 	};
 }
 
@@ -59,6 +99,10 @@ async function callShutdown(context: ShutdownThis, options?: { fromSignal?: bool
 describe("InteractiveMode.shutdown ordering (#5080)", () => {
 	afterEach(() => {
 		vi.restoreAllMocks();
+		restoreStdoutIsTTY();
+		for (const dir of tempDirs.splice(0)) {
+			rmSync(dir, { recursive: true, force: true });
+		}
 	});
 
 	test("signal-triggered shutdown emits session_shutdown before terminal writes", async () => {
@@ -87,6 +131,43 @@ describe("InteractiveMode.shutdown ordering (#5080)", () => {
 		expect(order).toEqual(["drainInput", "stop", "dispose"]);
 	});
 
+	test("interactive quit prints a resume hint for persisted sessions", async () => {
+		vi.spyOn(process, "exit").mockImplementation((() => {
+			throw new ProcessExitError();
+		}) as typeof process.exit);
+		const stdoutWrite = vi
+			.spyOn(process.stdout, "write")
+			.mockImplementation((() => true) as typeof process.stdout.write);
+		setStdoutIsTTY(true);
+		const order: string[] = [];
+		const context = createContext(order, createSessionManager({ sessionFile: createTempFile() }));
+
+		await callShutdown(context);
+
+		expect(order).toEqual(["drainInput", "stop", "dispose"]);
+		expect(stdoutWrite).toHaveBeenCalledWith(
+			`  ${chalk.dim("To resume this session:")} ${APP_NAME} --session test-session\n`,
+		);
+	});
+
+	test("signal-triggered shutdown does not print a resume hint", async () => {
+		vi.spyOn(process, "exit").mockImplementation((() => {
+			throw new ProcessExitError();
+		}) as typeof process.exit);
+		const stdoutWrite = vi
+			.spyOn(process.stdout, "write")
+			.mockImplementation((() => true) as typeof process.stdout.write);
+		setStdoutIsTTY(true);
+		const order: string[] = [];
+		const context = createContext(order, createSessionManager({ sessionFile: createTempFile() }));
+
+		await callShutdown(context, { fromSignal: true });
+
+		for (const call of stdoutWrite.mock.calls) {
+			expect(call[0]).not.toContain("To resume this session:");
+		}
+	});
+
 	test("re-entrant shutdown is a no-op", async () => {
 		vi.spyOn(process, "exit").mockImplementation((() => {
 			throw new ProcessExitError();