Force-kill stalled E2E teardown (verify Windows E2E hang fix)

.buildkite/commands/run-e2e-tests.sh

@@ -174,12 +174,33 @@ else
   echo 'Installing Playwright browsers...'
   npx playwright install
 
+  # TEMP(AINFRA-2588 probe): Windows E2E hangs *after* the Playwright suite finishes
+  # (~26 min) — the runner process never exits and the job runs to the 180-min timeout.
+  # Snapshot the surviving process tree while it is hung to find the leaked child/handle.
+  # Runs in the background so it fires even though `npx playwright test` never returns.
+  probe_pid=''
+  if [ "$PLATFORM" = "windows" ]; then
+    (
+      snapshot() {
+        echo "--- :mag: [hang-probe] surviving node/Studio/php processes at ${1}"
+        powershell -NoProfile -NonInteractive -Command "Get-CimInstance Win32_Process | Where-Object { \$_.Name -match 'node|Studio|php|electron|Squirrel' } | Select-Object ProcessId,ParentProcessId,Name,CommandLine | Format-Table -AutoSize -Wrap | Out-String -Width 1000" || true
+      }
+      sleep 2400; snapshot '40m'
+      sleep 1800; snapshot '70m'
+    ) &
+    probe_pid=$!
+  fi
+
   echo 'Running Playwright tests...'
   # Capture the exit code so a failure doesn't trip `set -e` before we collect
   # the daemon logs (~/.studio/daemon/logs) for artifact upload.
   test_exit=0
   npx playwright test || test_exit=$?
 
+  if [ -n "$probe_pid" ]; then
+    kill "$probe_pid" 2>/dev/null || true
+  fi
+
   if [ "$test_exit" -ne 0 ] && [ -d "$HOME/.studio/daemon/logs" ]; then
     mkdir -p test-results/daemon-logs
     cp -r "$HOME/.studio/daemon/logs/." test-results/daemon-logs/ || true

.buildkite/pipeline.yml

@@ -23,9 +23,9 @@ e2e_config: &e2e_config
     setup: { platform: [], arch: [] }
     adjustments:
       - with: { platform: mac, arch: arm64 }
-      # Windows E2E temporarily disabled while AINFRA-2588 investigates Windows E2E hangs in Buildkite.
-      # See https://linear.app/a8c/issue/AINFRA-2588/investigate-studio-windows-e2e-hangs-in-buildkite
-      # - with: { platform: windows, arch: x64 }
+      # TEMP(AINFRA-2588): Windows E2E re-enabled here to verify the closeApp() force-kill teardown
+      # fix lands the job under the 180-min timeout. Revert to the disabled form before merge.
+      - with: { platform: windows, arch: x64 }
   notify:
     - github_commit_status:
         context: E2E Tests

apps/studio/e2e/e2e-helpers.ts

@@ -1,4 +1,5 @@
 import { randomUUID } from 'crypto';
+import { spawnSync } from 'node:child_process';
 import { tmpdir } from 'os';
 import path from 'path';
 import { findLatestBuild, parseElectronApp } from 'electron-playwright-helpers';
@@ -80,7 +81,16 @@ export class E2ESession {
 			await new Promise< void >( ( resolve ) => setTimeout( resolve, 2000 ) );
 			console.log( 'App closed successfully' );
 		} catch ( error ) {
-			console.log( 'Process exit timeout' );
+			// The graceful quit stalled — a leaky IPC handler or a `site stop --all` child that
+			// won't exit keeps Electron alive (notably on Windows). Force-kill the process tree so
+			// the Playwright runner can exit, instead of leaving an orphaned process that blocks the
+			// run until the CI job timeout.
+			console.log( 'Process exit timeout; force-killing the app process tree' );
+			forceKillProcessTree( childProcess );
+			await Promise.race( [
+				exitPromise,
+				new Promise< void >( ( resolve ) => setTimeout( resolve, 5_000 ) ),
+			] );
 		} finally {
 			this.stopCapturingMainProcessLogs();
 		}
@@ -223,3 +233,23 @@ export class E2ESession {
 		return this.mainProcessLogs.join( '' ).trim();
 	}
 }
+
+function forceKillProcessTree( childProcess: ChildProcess ): void {
+	const { pid } = childProcess;
+	if ( ! pid ) {
+		return;
+	}
+
+	// `child.kill()` only signals the Electron main process; on Windows its renderer and php.exe
+	// descendants orphan and keep DLLs locked, so walk the whole tree with `taskkill /T`. Mirrors
+	// `killChild` in tools/common/lib/cli-process.ts.
+	if ( process.platform === 'win32' ) {
+		spawnSync( 'taskkill', [ '/F', '/T', '/PID', String( pid ) ], {
+			windowsHide: true,
+			stdio: 'ignore',
+		} );
+		return;
+	}
+
+	childProcess.kill( 'SIGKILL' );
+}

apps/studio/e2e/global-teardown.ts

@@ -0,0 +1,59 @@
+import { execFileSync } from 'node:child_process';
+
+/**
+ * The E2E suite drives Studio, which spawns a long-lived CLI process-manager daemon
+ * (`resources/cli/process-manager-daemon.mjs`) to run each site's PHP servers. On Windows
+ * the daemon is orphaned when the Electron app quits and survives with its
+ * `php-server-child.mjs` / `php.exe` subtree; the Playwright runner then holds an open
+ * handle to it and never exits, so the CI job hangs to the 180-min timeout (AINFRA-2588).
+ * `closeApp()` / `site stop --all` don't reap it. Once the whole suite is done nothing
+ * needs the daemon, so kill any survivors here to let the runner exit.
+ */
+export default function globalTeardown() {
+	if ( process.platform === 'win32' ) {
+		reapWindowsStudioDaemons();
+	} else {
+		reapUnixStudioDaemons();
+	}
+}
+
+function reapWindowsStudioDaemons() {
+	const query =
+		'Get-CimInstance Win32_Process | ' +
+		"Where-Object { $_.CommandLine -match 'process-manager-daemon\\.mjs' } | " +
+		'Select-Object -ExpandProperty ProcessId';
+
+	let pids: string[] = [];
+	try {
+		const out = execFileSync(
+			'powershell',
+			[ '-NoProfile', '-NonInteractive', '-Command', query ],
+			{ encoding: 'utf8' }
+		);
+		pids = out.split( /\s+/ ).filter( Boolean );
+	} catch {
+		// No daemon found, or powershell unavailable — nothing to reap.
+		return;
+	}
+
+	// `taskkill /T` walks the tree, killing the daemon's php-server-child.mjs and php.exe
+	// descendants along with it.
+	for ( const pid of pids ) {
+		try {
+			execFileSync( 'taskkill', [ '/F', '/T', '/PID', pid ], { stdio: 'ignore' } );
+			console.log( `[global-teardown] killed lingering Studio daemon tree (pid ${ pid })` );
+		} catch {
+			// Already exited between the query and the kill.
+		}
+	}
+}
+
+function reapUnixStudioDaemons() {
+	// macOS/Linux don't exhibit the hang, but reap any lingering daemon by command-line
+	// match so a leak can't regress silently. `pkill` exits non-zero when nothing matches.
+	try {
+		execFileSync( 'pkill', [ '-f', 'process-manager-daemon\\.mjs' ], { stdio: 'ignore' } );
+	} catch {
+		// Nothing matched — fine.
+	}
+}

playwright.config.ts

@@ -4,6 +4,10 @@ export default defineConfig( {
 	testDir: './apps/studio/e2e',
 	snapshotPathTemplate: '{testDir}/__screenshots__/{testFilePath}/{arg}{ext}',
 
+	// Reap Studio's orphaned CLI process-manager daemon after the suite so the runner can
+	// exit instead of hanging to the CI timeout on Windows (AINFRA-2588).
+	globalTeardown: './apps/studio/e2e/global-teardown.ts',
+
 	// The app only allows a single instance to be running at a time, so we can
 	// only run one test at a time.
 	workers: 1,