fix(qa-lab): bound Node binary lookup (#109428)

extensions/qa-lab/src/node-exec.test.ts

@@ -1,6 +1,6 @@
 // Qa Lab tests cover node exec plugin behavior.
 import path from "node:path";
-import { beforeEach, describe, expect, it, vi } from "vitest";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
 const { runExecMock } = vi.hoisted(() => ({ runExecMock: vi.fn() }));
 
@@ -13,6 +13,10 @@ describe("resolveQaNodeExecPath", () => {
     runExecMock.mockReset();
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it("reuses the current exec path when already running under Node", async () => {
     await expect(
       resolveQaNodeExecPath({
@@ -66,6 +70,7 @@ describe("resolveQaNodeExecPath", () => {
     expect(runExecMock).toHaveBeenCalledWith("which", ["node"], {
       baseEnv: env,
       logOutput: false,
+      timeoutMs: 5_000,
     });
   });
 
@@ -82,6 +87,7 @@ describe("resolveQaNodeExecPath", () => {
           expect(options).toEqual({
             encoding: "utf8",
             env: { SystemRoot: String.raw`D:\Windows` },
+            timeoutMs: 5_000,
           });
           return {
             stdout: String.raw`D:\nodejs\node.exe` + "\r\n",
@@ -92,6 +98,33 @@ describe("resolveQaNodeExecPath", () => {
     ).resolves.toBe(String.raw`D:\nodejs\node.exe`);
   });
 
+  it("fails after the lookup timeout when the PATH probe stalls", async () => {
+    vi.useFakeTimers();
+    runExecMock.mockImplementationOnce(
+      (_file: string, _args: string[], options: { timeoutMs: number }): Promise<never> =>
+        new Promise((_resolve, reject) => {
+          setTimeout(() => reject(new Error("timed out")), options.timeoutMs);
+        }),
+    );
+
+    const lookup = resolveQaNodeExecPath({
+      execPath: "/opt/homebrew/bin/bun",
+      platform: "darwin",
+      versions: { ...process.versions, bun: "1.2.3" },
+    });
+    const rejection = lookup.catch((error: unknown) => error);
+
+    await vi.advanceTimersByTimeAsync(5_000);
+    await expect(rejection).resolves.toEqual(
+      expect.objectContaining({ message: expect.stringContaining("Node not found in PATH") }),
+    );
+    expect(runExecMock).toHaveBeenCalledWith("which", ["node"], {
+      baseEnv: undefined,
+      logOutput: false,
+      timeoutMs: 5_000,
+    });
+  });
+
   it("throws a clear error when node is unavailable", async () => {
     await expect(
       resolveQaNodeExecPath({

extensions/qa-lab/src/node-exec.ts

@@ -9,11 +9,18 @@ type ExecFileAsync = (
   options: {
     encoding: "utf8";
     env?: NodeJS.ProcessEnv;
+    timeoutMs: number;
   },
 ) => Promise<{ stdout: string; stderr: string }>;
 
+const NODE_BINARY_LOOKUP_TIMEOUT_MS = 5_000;
+
 const execFileAsync: ExecFileAsync = async (file, args, options) =>
-  await runExec(file, [...args], { baseEnv: options.env, logOutput: false });
+  await runExec(file, [...args], {
+    baseEnv: options.env,
+    logOutput: false,
+    timeoutMs: options.timeoutMs,
+  });
 
 function isNodeExecPath(execPath: string, platform: NodeJS.Platform): boolean {
   const pathModule = platform === "win32" ? path.win32 : path.posix;
@@ -48,6 +55,7 @@ export async function resolveQaNodeExecPath(params?: {
     ({ stdout } = await execFileImpl(locator, ["node"], {
       encoding: "utf8",
       env: params?.env,
+      timeoutMs: NODE_BINARY_LOOKUP_TIMEOUT_MS,
     }));
   } catch {
     throw new Error(