vm: fix async hook stack after microtask timeout

Assisted-by: Claude Code
Signed-off-by: lazerg <lazerg2@gmail.com>

Author: lazerg

src/node_contextify.cc

@@ -1286,6 +1286,8 @@ bool ContextifyScript::EvalMachine(Local<Context> context,
   MaybeLocal<Value> result;
   bool timed_out = false;
   bool received_signal = false;
+  const uint32_t async_stack_length =
+      env->async_hooks()->fields()[AsyncHooks::kStackLength];
   {
     auto wd = timeout != -1 ? std::make_optional<Watchdog>(
                                   env->isolate(), timeout, &timed_out)
@@ -1304,6 +1306,13 @@ bool ContextifyScript::EvalMachine(Local<Context> context,
     if (!env->is_main_thread() && env->is_stopping())
       return false;
     env->isolate()->CancelTerminateExecution();
+    // A promise job terminated by the watchdog never runs its async hook
+    // `after` callback, so drop the contexts it left on the stack.
+    AsyncHooks* async_hooks = env->async_hooks();
+    while (async_hooks->fields()[AsyncHooks::kStackLength] >
+           async_stack_length) {
+      async_hooks->pop_async_context(env->execution_async_id());
+    }
     // It is possible that execution was terminated by another timeout in
     // which this timeout is nested, so check whether one of the watchdogs
     // from this invocation is responsible for termination.

test/parallel/test-async-hooks-vm-timeout.js

@@ -0,0 +1,24 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const async_hooks = require('async_hooks');
+const vm = require('vm');
+
+async_hooks.createHook({ init() {} }).enable();
+
+const executionAsyncId = async_hooks.executionAsyncId();
+const context = vm.createContext({}, { microtaskMode: 'afterEvaluate' });
+
+assert.throws(() => {
+  vm.runInContext(
+    'Promise.resolve().then(() => { while (true); });',
+    context,
+    { timeout: 5 }
+  );
+}, {
+  code: 'ERR_SCRIPT_EXECUTION_TIMEOUT',
+});
+
+assert.strictEqual(async_hooks.executionAsyncId(), executionAsyncId);
+setImmediate(common.mustCall());