test: deflake debugger PID attachment and cleanup

Wait for the target to finish starting before attaching the debugger.
Capture the CLI close event when it is spawned so quit() also completes
after an early exit, and terminate the target before awaiting cleanup.
Add a regression test for quitting an already exited CLI and remove the
Windows flaky entry.

Refs: #63212
Signed-off-by: Filip Skokan <panva.ip@gmail.com>
Assisted-by: Codex
PR-URL: #66320
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: panva

test/common/debugger.js

@@ -27,6 +27,8 @@ function startCLI(args, flags = [], spawnOpts = {}, opts = { randomPort: true })
     ...args,
   ], spawnOpts);
 
+  const closed = new Promise((resolve) => child.once('close', resolve));
+
   const outputBuffer = [];
   function bufferOutput(chunk) {
     if (this === child.stderr) {
@@ -180,10 +182,8 @@ function startCLI(args, flags = [], spawnOpts = {}, opts = { randomPort: true })
     },
 
     quit() {
-      return new Promise((resolve) => {
-        child.stdin.end();
-        child.on('close', resolve);
-      });
+      child.stdin.end();
+      return closed;
     },
   };
 }

test/fixtures/debugger/alive.js

@@ -3,3 +3,5 @@ function heartbeat() {
   ++x;
 }
 setInterval(heartbeat, 50);
+
+if (process.send) process.send('ready');

test/sequential/sequential.status

@@ -11,8 +11,6 @@ test-cpu-prof-dir-worker: PASS, FLAKY
 test-http2-large-file: PASS, FLAKY
 
 [$system==win32]
-# https://github.com/nodejs/node/issues/63212#issuecomment-5423558796
-test-debugger-pid: PASS, FLAKY
 
 [$system==linux]
 # https://github.com/nodejs/node/issues/54817

test/sequential/test-debugger-pid.js

@@ -8,11 +8,15 @@ const startCLI = require('../common/debugger');
 
 const assert = require('assert');
 const { spawn } = require('child_process');
+const { once } = require('events');
 
 const script = fixtures.path('debugger', 'alive.js');
 
 (async () => {
-  const target = spawn(process.execPath, [script]);
+  const target = spawn(process.execPath, [script], {
+    stdio: ['ignore', 'pipe', 'pipe', 'ipc'],
+  });
+  await once(target, 'message');
   const cli = startCLI(['-p', `${target.pid}`], [], {}, { randomPort: false });
 
   try {
@@ -25,7 +29,8 @@ const script = fixtures.path('debugger', 'alive.js');
       /> 3 {3}\+\+x;/,
       'marks the 3rd line');
   } finally {
-    await cli.quit();
+    const targetClosed = once(target, 'close');
     target.kill();
+    await Promise.all([cli.quit(), targetClosed]);
   }
 })().then(common.mustCall());

test/sequential/test-debugger-quit-after-exit.js

@@ -0,0 +1,12 @@
+'use strict';
+const common = require('../common');
+common.skipIfInspectorDisabled();
+
+const assert = require('assert');
+const startCLI = require('../common/debugger');
+
+(async () => {
+  const cli = startCLI(['--help'], [], {}, { randomPort: false });
+  await assert.rejects(cli.waitForPrompt(), /Child exited while waiting/);
+  await cli.quit();
+})().then(common.mustCall());