lib,src: eagerly exit process on unhanded promise rejections

lib/internal/bootstrap_node.js

@@ -304,13 +304,13 @@
 
   function setupProcessFatal() {
 
-    process._fatalException = function(er) {
+    process._fatalException = function(er, fromPromise) {
       var caught;
 
       if (process.domain && process.domain._errorHandler)
         caught = process.domain._errorHandler(er) || caught;
 
-      if (!caught)
+      if (!caught && !fromPromise)
         caught = process.emit('uncaughtException', er);
 
       // If someone handled it, then great.  otherwise, die in C++ land

lib/internal/process/promises.js

@@ -2,17 +2,10 @@
 
 const promiseRejectEvent = process._promiseRejectEvent;
 const hasBeenNotifiedProperty = new WeakMap();
-const promiseToGuidProperty = new WeakMap();
 const pendingUnhandledRejections = [];
-let lastPromiseId = 1;
 
 exports.setup = setupPromises;
 
-function getAsynchronousRejectionWarningObject(uid) {
-  return new Error('Promise rejection was handled ' +
-                   `asynchronously (rejection id: ${uid})`);
-}
-
 function setupPromises(scheduleMicrotasks) {
   process._setupPromises(function(event, promise, reason) {
     if (event === promiseRejectEvent.unhandled)
@@ -25,65 +18,31 @@ function setupPromises(scheduleMicrotasks) {
 
   function unhandledRejection(promise, reason) {
     hasBeenNotifiedProperty.set(promise, false);
-    promiseToGuidProperty.set(promise, lastPromiseId++);
     addPendingUnhandledRejection(promise, reason);
   }
 
   function rejectionHandled(promise) {
     const hasBeenNotified = hasBeenNotifiedProperty.get(promise);
     if (hasBeenNotified !== undefined) {
       hasBeenNotifiedProperty.delete(promise);
-      const uid = promiseToGuidProperty.get(promise);
-      promiseToGuidProperty.delete(promise);
       if (hasBeenNotified === true) {
-        let warning = null;
-        if (!process.listenerCount('rejectionHandled')) {
-          // Generate the warning object early to get a good stack trace.
-          warning = getAsynchronousRejectionWarningObject(uid);
-        }
         process.nextTick(function() {
-          if (!process.emit('rejectionHandled', promise)) {
-            if (warning === null)
-              warning = getAsynchronousRejectionWarningObject(uid);
-            warning.name = 'PromiseRejectionHandledWarning';
-            warning.id = uid;
-            process.emitWarning(warning);
-          }
+          process.emit('rejectionHandled', promise);
         });
       }
 
     }
   }
 
-  function emitWarning(uid, reason) {
-    const warning = new Error('Unhandled promise rejection ' +
-                              `(rejection id: ${uid}): ${reason}`);
-    warning.name = 'UnhandledPromiseRejectionWarning';
-    warning.id = uid;
-    if (reason instanceof Error) {
-      warning.stack = reason.stack;
-    }
-    process.emitWarning(warning);
-    if (!deprecationWarned) {
-      deprecationWarned = true;
-      process.emitWarning(
-        'Unhandled promise rejections are deprecated. In the future, ' +
-        'promise rejections that are not handled will terminate the ' +
-        'Node.js process with a non-zero exit code.',
-        'DeprecationWarning', 'DEP0018');
-    }
-  }
-  var deprecationWarned = false;
   function emitPendingUnhandledRejections() {
     let hadListeners = false;
     while (pendingUnhandledRejections.length > 0) {
       const promise = pendingUnhandledRejections.shift();
       const reason = pendingUnhandledRejections.shift();
       if (hasBeenNotifiedProperty.get(promise) === false) {
         hasBeenNotifiedProperty.set(promise, true);
-        const uid = promiseToGuidProperty.get(promise);
         if (!process.emit('unhandledRejection', reason, promise)) {
-          emitWarning(uid, reason);
+          process.promiseFatal(promise);
         } else {
           hadListeners = true;
         }

src/node.cc

@@ -1286,6 +1286,21 @@ void SetupPromises(const FunctionCallbackInfo<Value>& args) {
       FIXED_ONE_BYTE_STRING(args.GetIsolate(), "_setupPromises")).FromJust();
 }
 
+void PromiseFatal(const FunctionCallbackInfo<Value>& args) {
+  CHECK(args[0]->IsPromise());
+
+  Environment* env = Environment::GetCurrent(args);
+  Isolate* isolate = env->isolate();
+
+  Local<Promise> promise = args[0].As<Promise>();
+
+  CHECK(promise->State() == Promise::PromiseState::kRejected);
+  Local<Value> err = promise->Result();
+  Local<Message> message = Exception::CreateMessage(isolate, err);
+
+  InternalFatalException(isolate, err, message, true);
+}
+
 }  // anonymous namespace
 
 
@@ -1719,10 +1734,9 @@ void AppendExceptionLine(Environment* env,
             arrow_str).FromMaybe(false));
 }
 
-
-static void ReportException(Environment* env,
-                            Local<Value> er,
-                            Local<Message> message) {
+void ReportException(Environment* env,
+                     Local<Value> er,
+                     Local<Message> message) {
   HandleScope scope(env->isolate());
 
   AppendExceptionLine(env, er, message, FATAL_ERROR);
@@ -2615,6 +2629,14 @@ NO_RETURN void FatalError(const char* location, const char* message) {
 void FatalException(Isolate* isolate,
                     Local<Value> error,
                     Local<Message> message) {
+  InternalFatalException(isolate, error, message, false);
+}
+
+
+void InternalFatalException(Isolate* isolate,
+                            Local<Value> error,
+                            Local<Message> message,
+                            bool from_promise) {
   HandleScope scope(isolate);
 
   Environment* env = Environment::GetCurrent(isolate);
@@ -2637,9 +2659,12 @@ void FatalException(Isolate* isolate,
     // Do not call FatalException when _fatalException handler throws
     fatal_try_catch.SetVerbose(false);
 
+    Local<Value> argv[2] = { error,
+                             Boolean::New(env->isolate(), from_promise) };
+
     // this will return true if the JS layer handled it, false otherwise
     Local<Value> caught =
-        fatal_exception_function->Call(process_object, 1, &error);
+        fatal_exception_function->Call(process_object, 2, argv);
 
     if (fatal_try_catch.HasCaught()) {
       // the fatal exception function threw, so we must exit
@@ -3495,6 +3520,8 @@ void SetupProcessObject(Environment* env,
   env->SetMethod(process, "_setupPromises", SetupPromises);
   env->SetMethod(process, "_setupDomainUse", SetupDomainUse);
 
+  env->SetMethod(process, "promiseFatal", PromiseFatal);
+
   // pre-set _events object for faster emit checks
   Local<Object> events_obj = Object::New(env->isolate());
   CHECK(events_obj->SetPrototype(env->context(),

src/node_internals.h

@@ -168,6 +168,11 @@ void AppendExceptionLine(Environment* env,
                          v8::Local<v8::Message> message,
                          enum ErrorHandlingMode mode);
 
+void InternalFatalException(v8::Isolate* isolate,
+                            v8::Local<v8::Value> error,
+                            v8::Local<v8::Message> message,
+                            bool from_promise);
+
 NO_RETURN void FatalError(const char* location, const char* message);
 
 void ProcessEmitWarning(Environment* env, const char* fmt, ...);

test/message/promise_fast_handled_reject.js

@@ -0,0 +1,26 @@
+'use strict';
+const common = require('../common');
+
+const p1 = new Promise((res, rej) => {
+  consol.log('One'); // eslint-disable-line no-undef
+});
+
+const p2 = new Promise((res, rej) => { // eslint-disable-line no-unused-vars
+  consol.log('Two'); // eslint-disable-line no-undef
+});
+
+const p3 = new Promise((res, rej) => {
+  consol.log('Three'); // eslint-disable-line no-undef
+});
+
+new Promise((res, rej) => {
+  setTimeout(common.mustCall(() => {
+    p1.catch(() => {});
+    p3.catch(() => {});
+  }), 1);
+});
+
+process.on('uncaughtException', (err) =>
+    common.fail('Should not trigger uncaught exception'));
+
+process.on('exit', () => process._rawDebug('exit event emitted'));

test/message/promise_fast_handled_reject.out

@@ -0,0 +1,16 @@
+exit event emitted
+*test*message*promise_fast_handled_reject.js:*
+  consol.log('One'); // eslint-disable-line no-undef
+  ^
+
+ReferenceError: consol is not defined
+    at Promise (*test*message*promise_fast_handled_reject.js:*:*)
+    at Promise (<anonymous>)
+    at Object.<anonymous> (*test*message*promise_fast_handled_reject.js:*:*)
+    at Module._compile (module.js:*:*)
+    at Object.Module._extensions..js (module.js:*:*)
+    at Module.load (module.js:*:*)
+    at tryModuleLoad (module.js:*:*)
+    at Function.Module._load (module.js:*:*)
+    at Function.Module.runMain (module.js:*:*)
+    at startup (bootstrap_node.js:*:*)

test/message/promise_fast_reject.js

@@ -0,0 +1,18 @@
+'use strict';
+
+// We should always have the stacktrace of the oldest rejection.
+
+const common = require('../common');
+
+new Promise(function(res, rej) {
+  consol.log('One'); // eslint-disable-line no-undef
+});
+
+new Promise(function(res, rej) {
+  consol.log('Two'); // eslint-disable-line no-undef
+});
+
+process.on('uncaughtException', (err) =>
+    common.fail('Should not trigger uncaught exception'));
+
+process.on('exit', () => process._rawDebug('exit event emitted'));

test/message/promise_fast_reject.out

@@ -0,0 +1,16 @@
+exit event emitted
+*test*message*promise_fast_reject.js:*
+  consol.log('One'); // eslint-disable-line no-undef
+  ^
+
+ReferenceError: consol is not defined
+    at *test*message*promise_fast_reject.js:*:*
+    at Promise (<anonymous>)
+    at Object.<anonymous> (*test*message*promise_fast_reject.js:*:*)
+    at Module._compile (module.js:*:*)
+    at Object.Module._extensions..js (module.js:*:*)
+    at Module.load (module.js:*:*)
+    at tryModuleLoad (module.js:*:*)
+    at Function.Module._load (module.js:*:*)
+    at Function.Module.runMain (module.js:*:*)
+    at startup (bootstrap_node.js:*:*)

test/message/promise_reject.js

@@ -0,0 +1,18 @@
+'use strict';
+const common = require('../common');
+
+
+Promise.reject(new Error('oops'));
+
+setImmediate(() => {
+  common.fail('Should not reach Immediate');
+});
+
+process.on('beforeExit', () =>
+    common.fail('beforeExit should not be reached'));
+
+process.on('uncaughtException', (err) => {
+  common.fail('Should not trigger uncaught exception');
+});
+
+process.on('exit', () => process._rawDebug('exit event emitted'));

test/message/promise_reject.out

@@ -0,0 +1,15 @@
+exit event emitted
+*test*message*promise_reject.js:*
+Promise.reject(new Error('oops'));
+               ^
+
+Error: oops
+    at *test*message*promise_reject.js:*:*
+    at Module._compile (module.js:*:*)
+    at Object.Module._extensions..js (module.js:*:*)
+    at Module.load (module.js:*:*)
+    at tryModuleLoad (module.js:*:*)
+    at Function.Module._load (module.js:*:*)
+    at Function.Module.runMain (module.js:*:*)
+    at startup (bootstrap_node.js:*:*)
+    at bootstrap_node.js:*:*

test/parallel/test-promises-handled-reject.js

@@ -0,0 +1,19 @@
+'use strict';
+const common = require('../common');
+
+// Flags: --expose-gc
+
+const p = new Promise((res, rej) => {
+  consol.log('oops'); // eslint-disable-line no-undef
+});
+
+// Manually call GC due to possible memory contraints with attempting to
+// trigger it "naturally".
+process.nextTick(common.mustCall(() => {
+  p.catch(() => {});
+  /* eslint-disable no-undef */
+  gc();
+  gc();
+  gc();
+  /* eslint-enable no-undef */
+}, 1));

test/parallel/test-promises-unhandled-rejections.js

@@ -1,5 +1,5 @@
 'use strict';
-require('../common');
+const common = require('../common');
 const assert = require('assert');
 const domain = require('domain');
 
@@ -673,6 +673,8 @@ asyncTest('Throwing an error inside a rejectionHandled handler goes to' +
     tearDownException();
     done();
   });
+  // Prevent fatal unhandled error.
+  process.on('unhandledRejection', common.noop);
   process.on('rejectionHandled', function() {
     throw e2;
   });