src: refactor tickInfo access

- Wrap access to tickInfo fields in functions
- Rename `kHasScheduled` to `kHasTickScheduled` and
  `kHasPromiseRejections` to `kHasRejectionToWarn` for clarity - note
  the latter will be set to false if the rejection does not lead to
  a warning so the previous description is not accurate.
- Set `kHasRejectionToWarn` in JS land of relying on C++ to use
  an implict contract (return value of the promise rejection handler)
  to set it, as the decision is made entirely in JS land.
- Destructure promise reject event constants.

PR-URL: #25200
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/process/next_tick.js

@@ -11,6 +11,8 @@ const {
 } = internalBinding('task_queue');
 
 const {
+  setHasRejectionToWarn,
+  hasRejectionToWarn,
   promiseRejectHandler,
   emitPromiseRejectionWarnings
 } = require('internal/process/promises');
@@ -30,15 +32,21 @@ const { ERR_INVALID_CALLBACK } = require('internal/errors').codes;
 const FixedQueue = require('internal/fixed_queue');
 
 // *Must* match Environment::TickInfo::Fields in src/env.h.
-const kHasScheduled = 0;
-const kHasPromiseRejections = 1;
+const kHasTickScheduled = 0;
+
+function hasTickScheduled() {
+  return tickInfo[kHasTickScheduled] === 1;
+}
+function setHasTickScheduled(value) {
+  tickInfo[kHasTickScheduled] = value ? 1 : 0;
+}
 
 const queue = new FixedQueue();
 
 function runNextTicks() {
-  if (tickInfo[kHasScheduled] === 0 && tickInfo[kHasPromiseRejections] === 0)
+  if (!hasTickScheduled() && !hasRejectionToWarn())
     runMicrotasks();
-  if (tickInfo[kHasScheduled] === 0 && tickInfo[kHasPromiseRejections] === 0)
+  if (!hasTickScheduled() && !hasRejectionToWarn())
     return;
 
   internalTickCallback();
@@ -70,10 +78,10 @@ function internalTickCallback() {
 
       emitAfter(asyncId);
     }
-    tickInfo[kHasScheduled] = 0;
+    setHasTickScheduled(false);
     runMicrotasks();
   } while (!queue.isEmpty() || emitPromiseRejectionWarnings());
-  tickInfo[kHasPromiseRejections] = 0;
+  setHasRejectionToWarn(false);
 }
 
 class TickObject {
@@ -119,7 +127,7 @@ function nextTick(callback) {
   }
 
   if (queue.isEmpty())
-    tickInfo[kHasScheduled] = 1;
+    setHasTickScheduled(true);
   queue.push(new TickObject(callback, args, getDefaultTriggerAsyncId()));
 }
 

lib/internal/process/promises.js

@@ -2,24 +2,45 @@
 
 const { safeToString } = internalBinding('util');
 const {
-  promiseRejectEvents
+  tickInfo,
+  promiseRejectEvents: {
+    kPromiseRejectWithNoHandler,
+    kPromiseHandlerAddedAfterReject,
+    kPromiseResolveAfterResolved,
+    kPromiseRejectAfterResolved
+  }
 } = internalBinding('task_queue');
 
+// *Must* match Environment::TickInfo::Fields in src/env.h.
+const kHasRejectionToWarn = 1;
+
 const maybeUnhandledPromises = new WeakMap();
 const pendingUnhandledRejections = [];
 const asyncHandledRejections = [];
 let lastPromiseId = 0;
 
+function setHasRejectionToWarn(value) {
+  tickInfo[kHasRejectionToWarn] = value ? 1 : 0;
+}
+
+function hasRejectionToWarn() {
+  return tickInfo[kHasRejectionToWarn] === 1;
+}
+
 function promiseRejectHandler(type, promise, reason) {
   switch (type) {
-    case promiseRejectEvents.kPromiseRejectWithNoHandler:
-      return unhandledRejection(promise, reason);
-    case promiseRejectEvents.kPromiseHandlerAddedAfterReject:
-      return handledRejection(promise);
-    case promiseRejectEvents.kPromiseResolveAfterResolved:
-      return resolveError('resolve', promise, reason);
-    case promiseRejectEvents.kPromiseRejectAfterResolved:
-      return resolveError('reject', promise, reason);
+    case kPromiseRejectWithNoHandler:
+      unhandledRejection(promise, reason);
+      break;
+    case kPromiseHandlerAddedAfterReject:
+      handledRejection(promise);
+      break;
+    case kPromiseResolveAfterResolved:
+      resolveError('resolve', promise, reason);
+      break;
+    case kPromiseRejectAfterResolved:
+      resolveError('reject', promise, reason);
+      break;
   }
 }
 
@@ -38,7 +59,7 @@ function unhandledRejection(promise, reason) {
     warned: false
   });
   pendingUnhandledRejections.push(promise);
-  return true;
+  setHasRejectionToWarn(true);
 }
 
 function handledRejection(promise) {
@@ -54,10 +75,11 @@ function handledRejection(promise) {
       warning.name = 'PromiseRejectionHandledWarning';
       warning.id = uid;
       asyncHandledRejections.push({ promise, warning });
-      return true;
+      setHasRejectionToWarn(true);
+      return;
     }
   }
-  return false;
+  setHasRejectionToWarn(false);
 }
 
 const unhandledRejectionErrName = 'UnhandledPromiseRejectionWarning';
@@ -121,6 +143,8 @@ function emitPromiseRejectionWarnings() {
 }
 
 module.exports = {
+  hasRejectionToWarn,
+  setHasRejectionToWarn,
   promiseRejectHandler,
   emitPromiseRejectionWarnings
 };

src/callback_scope.cc

@@ -95,7 +95,7 @@ void InternalCallbackScope::Close() {
   Environment::TickInfo* tick_info = env_->tick_info();
 
   if (!env_->can_call_into_js()) return;
-  if (!tick_info->has_scheduled()) {
+  if (!tick_info->has_tick_scheduled()) {
     env_->isolate()->RunMicrotasks();
   }
 
@@ -106,7 +106,7 @@ void InternalCallbackScope::Close() {
     CHECK_EQ(env_->trigger_async_id(), 0);
   }
 
-  if (!tick_info->has_scheduled() && !tick_info->has_promise_rejections()) {
+  if (!tick_info->has_tick_scheduled() && !tick_info->has_rejection_to_warn()) {
     return;
   }
 

src/env-inl.h

@@ -265,16 +265,12 @@ inline AliasedBuffer<uint8_t, v8::Uint8Array>& Environment::TickInfo::fields() {
   return fields_;
 }
 
-inline bool Environment::TickInfo::has_scheduled() const {
-  return fields_[kHasScheduled] == 1;
+inline bool Environment::TickInfo::has_tick_scheduled() const {
+  return fields_[kHasTickScheduled] == 1;
 }
 
-inline bool Environment::TickInfo::has_promise_rejections() const {
-  return fields_[kHasPromiseRejections] == 1;
-}
-
-inline void Environment::TickInfo::promise_rejections_toggle_on() {
-  fields_[kHasPromiseRejections] = 1;
+inline bool Environment::TickInfo::has_rejection_to_warn() const {
+  return fields_[kHasRejectionToWarn] == 1;
 }
 
 inline void Environment::AssignToContext(v8::Local<v8::Context> context,

src/env.h

@@ -572,18 +572,16 @@ class Environment {
   class TickInfo {
    public:
     inline AliasedBuffer<uint8_t, v8::Uint8Array>& fields();
-    inline bool has_scheduled() const;
-    inline bool has_promise_rejections() const;
-
-    inline void promise_rejections_toggle_on();
+    inline bool has_tick_scheduled() const;
+    inline bool has_rejection_to_warn() const;
 
    private:
     friend class Environment;  // So we can call the constructor.
     inline explicit TickInfo(v8::Isolate* isolate);
 
     enum Fields {
-      kHasScheduled,
-      kHasPromiseRejections,
+      kHasTickScheduled = 0,
+      kHasRejectionToWarn,
       kFieldsCount
     };
 

src/node_task_queue.cc

@@ -17,7 +17,6 @@ using v8::kPromiseRejectAfterResolved;
 using v8::kPromiseRejectWithNoHandler;
 using v8::kPromiseResolveAfterResolved;
 using v8::Local;
-using v8::MaybeLocal;
 using v8::Number;
 using v8::Object;
 using v8::Promise;
@@ -80,13 +79,8 @@ static void PromiseRejectCallback(PromiseRejectMessage message) {
   }
 
   Local<Value> args[] = { type, promise, value };
-  MaybeLocal<Value> ret = callback->Call(env->context(),
-                                         Undefined(isolate),
-                                         arraysize(args),
-                                         args);
-
-  if (!ret.IsEmpty() && ret.ToLocalChecked()->IsTrue())
-    env->tick_info()->promise_rejections_toggle_on();
+  USE(callback->Call(
+      env->context(), Undefined(isolate), arraysize(args), args));
 }
 
 static void InitializePromiseRejectCallback(