src: fix process exit listeners not receiving unsettled tla codes

fix listeners registered via `process.on('exit', ...` not receiving
error code 13 when an unsettled top-level-await is encountered in
the code

Author: dario-piotrowicz

src/api/embed_helpers.cc

@@ -73,20 +73,7 @@ Maybe<ExitCode> SpinEventLoopInternal(Environment* env) {
 
   env->PrintInfoForSnapshotIfDebug();
   env->ForEachRealm([](Realm* realm) { realm->VerifyNoStrongBaseObjects(); });
-  Maybe<ExitCode> exit_code = EmitProcessExitInternal(env);
-  if (exit_code.FromMaybe(ExitCode::kGenericUserError) !=
-      ExitCode::kNoFailure) {
-    return exit_code;
-  }
-
-  auto unsettled_tla = env->CheckUnsettledTopLevelAwait();
-  if (unsettled_tla.IsNothing()) {
-    return Nothing<ExitCode>();
-  }
-  if (!unsettled_tla.FromJust()) {
-    return Just(ExitCode::kUnsettledTopLevelAwait);
-  }
-  return Just(ExitCode::kNoFailure);
+  return EmitProcessExitInternal(env);
 }
 
 struct CommonEnvironmentSetup::Impl {

src/api/hooks.cc

@@ -70,14 +70,25 @@ Maybe<ExitCode> EmitProcessExitInternal(Environment* env) {
     return Nothing<ExitCode>();
   }
 
-  Local<Integer> exit_code = Integer::New(
-      isolate, static_cast<int32_t>(env->exit_code(ExitCode::kNoFailure)));
+  ExitCode exit_code = env->exit_code(ExitCode::kNoFailure);
+
+  // the exit code wasn't already set, so let's check for unsettled tlas
+  if (exit_code == ExitCode::kNoFailure) {
+    auto unsettled_tla = env->CheckUnsettledTopLevelAwait();
+    if (!unsettled_tla.FromJust()) {
+      exit_code = ExitCode::kUnsettledTopLevelAwait;
+    }
+  }
 
-  if (ProcessEmit(env, "exit", exit_code).IsEmpty()) {
+  Local<Integer> exit_code_int =
+      Integer::New(isolate, static_cast<int32_t>(exit_code));
+
+  if (ProcessEmit(env, "exit", exit_code_int).IsEmpty()) {
     return Nothing<ExitCode>();
   }
+
   // Reload exit code, it may be changed by `emit('exit')`
-  return Just(env->exit_code(ExitCode::kNoFailure));
+  return Just(env->exit_code(exit_code));
 }
 
 Maybe<int> EmitProcessExit(Environment* env) {

test/es-module/test-esm-tla-unfinished.mjs

@@ -72,24 +72,31 @@ describe('ESM: unsettled and rejected promises', { concurrency: !process.env.TES
   });
 
   it('should exit for an unsettled TLA promise with warning', async () => {
-    const { code, stderr, stdout } = await spawnPromisified(execPath, [
+    const { code, stderr } = await spawnPromisified(execPath, [
       fixtures.path('es-modules/tla/unresolved.mjs'),
     ]);
 
-    assert.match(stderr, /Warning: Detected unsettled top-level await at.+unresolved\.mjs:1/);
+    assert.match(stderr, /Warning: Detected unsettled top-level await at.+unresolved\.mjs:5/);
     assert.match(stderr, /await new Promise/);
-    assert.strictEqual(stdout, '');
+    assert.strictEqual(code, 13);
+  });
+
+  it('the process exit event should provide the correct code for an unsettled TLA promise', async () => {
+    const { code, stdout } = await spawnPromisified(execPath, [
+      fixtures.path('es-modules/tla/unresolved.mjs'),
+    ]);
+
+    assert.strictEqual(stdout, 'the exit listener received code: 13\n');
     assert.strictEqual(code, 13);
   });
 
   it('should exit for an unsettled TLA promise without warning', async () => {
-    const { code, stderr, stdout } = await spawnPromisified(execPath, [
+    const { code, stderr } = await spawnPromisified(execPath, [
       '--no-warnings',
       fixtures.path('es-modules/tla/unresolved.mjs'),
     ]);
 
     assert.strictEqual(stderr, '');
-    assert.strictEqual(stdout, '');
     assert.strictEqual(code, 13);
   });
 
@@ -105,13 +112,22 @@ describe('ESM: unsettled and rejected promises', { concurrency: !process.env.TES
   });
 
   it('should exit for an unsettled TLA promise and respect explicit exit code via stdin', async () => {
-    const { code, stderr, stdout } = await spawnPromisified(execPath, [
+    const { code, stderr } = await spawnPromisified(execPath, [
       '--no-warnings',
       fixtures.path('es-modules/tla/unresolved-withexitcode.mjs'),
     ]);
 
     assert.strictEqual(stderr, '');
-    assert.strictEqual(stdout, '');
+    assert.strictEqual(code, 42);
+  });
+
+  it('should exit for an unsettled TLA promise and respect explicit exit code in process exit event', async () => {
+    const { code, stdout } = await spawnPromisified(execPath, [
+      '--no-warnings',
+      fixtures.path('es-modules/tla/unresolved-withexitcode.mjs'),
+    ]);
+
+    assert.strictEqual(stdout, 'the exit listener received code: 42\n');
     assert.strictEqual(code, 42);
   });
 

test/fixtures/es-modules/tla/unresolved-withexitcode.mjs

@@ -1,2 +1,7 @@
+process.on('exit', (exitCode) => {
+    console.log(`the exit listener received code: ${exitCode}`);
+});
+
 process.exitCode = 42;
+
 await new Promise(() => {});

test/fixtures/es-modules/tla/unresolved.mjs

@@ -1 +1,5 @@
+process.on('exit', (exitCode) => {
+    console.log(`the exit listener received code: ${exitCode}`);
+})
+
 await new Promise(() => {});