Revert "fix(core): NgZone coaleascing options should trigger onStable correctly (#40540)"

This reverts commit 22f9e454a4.

packages/core/src/zone/ng_zone.ts

@@ -148,7 +148,6 @@ export class NgZone {
         !shouldCoalesceRunChangeDetection && shouldCoalesceEventChangeDetection;
     self.shouldCoalesceRunChangeDetection = shouldCoalesceRunChangeDetection;
     self.lastRequestAnimationFrameId = -1;
-    self.isCheckStableRunning = false;
     self.nativeRequestAnimationFrame = getNativeRequestAnimationFrame().nativeRequestAnimationFrame;
     forkInnerZoneWithAngularBehavior(self);
   }
@@ -244,17 +243,6 @@ interface NgZonePrivate extends NgZone {
   hasPendingMacrotasks: boolean;
   hasPendingMicrotasks: boolean;
   lastRequestAnimationFrameId: number;
-  /**
-   * A flag to indicate if NgZone is currently inside
-   * checkStable and to prevent re-entry. The flag is
-   * needed because it is possible to invoke the change
-   * detection from within change detection leading to
-   * incorrect behavior.
-   *
-   * For detail, please refer here,
-   * https://github.com/angular/angular/pull/40540
-   */
-  isCheckStableRunning: boolean;
   isStable: boolean;
   /**
    * Optionally specify coalescing event change detections or not.
@@ -303,9 +291,7 @@ interface NgZonePrivate extends NgZone {
 }
 
 function checkStable(zone: NgZonePrivate) {
-  if (!zone.isCheckStableRunning && zone._nesting == 0 && !zone.hasPendingMicrotasks &&
+  if (zone._nesting == 0 && !zone.hasPendingMicrotasks && !zone.isStable) {
-      !zone.isStable) {
-    zone.isCheckStableRunning = true;
     try {
       zone._nesting++;
       zone.onMicrotaskEmpty.emit(null);
@@ -318,26 +304,12 @@ function checkStable(zone: NgZonePrivate) {
           zone.isStable = true;
         }
       }
-      zone.isCheckStableRunning = false;
     }
   }
 }
 
 function delayChangeDetectionForEvents(zone: NgZonePrivate) {
-  /**
+  if (zone.lastRequestAnimationFrameId !== -1) {
-   * We also need to check isCheckStableRunning here
-   * Consider the following case with shouldCoalesceRunChangeDetection = true
-   *
-   * ngZone.run(() => {});
-   * ngZone.run(() => {});
-   *
-   * We want the two `ngZone.run()` only trigger one change detection
-   * when shouldCoalesceRunChangeDetection is true.
-   * And because in this case, change detection run in async way(requestAnimationFrame),
-   * so we also need to check the isCheckStableRunning here to prevent multiple
-   * change detections.
-   */
-  if (zone.isCheckStableRunning || zone.lastRequestAnimationFrameId !== -1) {
     return;
   }
   zone.lastRequestAnimationFrameId = zone.nativeRequestAnimationFrame.call(global, () => {

packages/core/test/zone/ng_zone_spec.ts

@@ -982,7 +982,6 @@ function commonTests() {
 
     describe('shouldCoalesceEventChangeDetection = true, shouldCoalesceRunChangeDetection = false', () => {
       let nativeRequestAnimationFrame: (fn: FrameRequestCallback) => void;
-      let nativeSetTimeout: any = (global as any)[Zone.__symbol__('setTimeout')];
       if (!(global as any).requestAnimationFrame) {
         nativeRequestAnimationFrame = function(fn: Function) {
           (global as any)[Zone.__symbol__('setTimeout')](fn, 16);
@@ -1043,32 +1042,6 @@ function commonTests() {
            });
          });
 
-      it('should only emit onMicroTaskEmpty once within the same event loop for ngZone.run in onMicrotaskEmpty subscription',
-         (done: DoneFn) => {
-           const tasks: Task[] = [];
-           coalesceZone.onMicrotaskEmpty.subscribe(() => {
-             coalesceZone.run(() => {});
-           });
-           coalesceZone.run(() => {
-             tasks.push(Zone.current.scheduleEventTask('myEvent', () => {
-               logs.push('eventTask1');
-             }, undefined, () => {}));
-           });
-           coalesceZone.run(() => {
-             tasks.push(Zone.current.scheduleEventTask('myEvent', () => {
-               logs.push('eventTask2');
-             }, undefined, () => {}));
-           });
-           tasks.forEach(t => t.invoke());
-           expect(logs).toEqual(['microTask empty', 'microTask empty', 'eventTask1', 'eventTask2']);
-           nativeSetTimeout(() => {
-             expect(logs).toEqual([
-               'microTask empty', 'microTask empty', 'eventTask1', 'eventTask2', 'microTask empty'
-             ]);
-             done();
-           }, 100);
-         });
-
       it('should emit onMicroTaskEmpty once within the same event loop for not only event tasks, but event tasks are before other tasks',
          (done: DoneFn) => {
            const tasks: Task[] = [];
@@ -1121,7 +1094,6 @@ function commonTests() {
 
     describe('shouldCoalesceRunChangeDetection = true', () => {
       let nativeRequestAnimationFrame: (fn: FrameRequestCallback) => void;
-      let nativeSetTimeout: any = (global as any)[Zone.__symbol__('setTimeout')];
       if (!(global as any).requestAnimationFrame) {
         nativeRequestAnimationFrame = function(fn: Function) {
           (global as any)[Zone.__symbol__('setTimeout')](fn, 16);
@@ -1167,20 +1139,6 @@ function commonTests() {
            });
          });
 
-      it('should only emit onMicroTaskEmpty once within the same event loop for ngZone.run in onMicrotaskEmpty subscription',
-         (done: DoneFn) => {
-           coalesceZone.onMicrotaskEmpty.subscribe(() => {
-             coalesceZone.run(() => {});
-           });
-           coalesceZone.run(() => {});
-           coalesceZone.run(() => {});
-           expect(logs).toEqual([]);
-           nativeSetTimeout(() => {
-             expect(logs).toEqual(['microTask empty']);
-             done();
-           }, 100);
-         });
-
       it('should only emit onMicroTaskEmpty once within the same event loop for multiple tasks',
          (done: DoneFn) => {
            const tasks: Task[] = [];