refactor(core): use ApplicationRef.whenStable instead of a custom util function

This commit removes a custom `whenStable` util in favor of standard `ApplicationRef.whenStable` API.

There is also an important different between the custom `whenStable` function and `ApplicationRef.whenStable` implementation: the `whenStable` was caching the "stable" promise on per-ApplicationRef basis, which resulted in unexpected behavior with zoneless, when some code ended up getting a stale resolved promise, when an application was not stable yet, this causing order of operations issues. This commit also has an extra test that covers that case.

Author: AndrewKushnir

packages/common/http/src/transfer_cache.ts

@@ -19,7 +19,6 @@ import {
   ɵformatRuntimeError as formatRuntimeError,
   ɵperformanceMarkFeature as performanceMarkFeature,
   ɵtruncateMiddle as truncateMiddle,
-  ɵwhenStable as whenStable,
   ɵRuntimeError as RuntimeError,
 } from '@angular/core';
 import {isPlatformServer} from '@angular/common';
@@ -338,7 +337,7 @@ export function withHttpTransferCache(cacheOptions: HttpTransferCacheOptions): P
         const cacheState = inject(CACHE_OPTIONS);
 
         return () => {
-          whenStable(appRef).then(() => {
+          appRef.whenStable().then(() => {
             cacheState.isCacheActive = false;
           });
         };

packages/common/src/directives/ng_optimized_image/ng_optimized_image.ts

@@ -31,7 +31,6 @@ import {
   ɵunwrapSafeValue as unwrapSafeValue,
   ChangeDetectorRef,
   ApplicationRef,
-  ɵwhenStable as whenStable,
 } from '@angular/core';
 
 import {RuntimeErrorCode} from '../../errors';
@@ -1310,7 +1309,7 @@ function assertNoLoaderParamsWithoutLoader(dir: NgOptimizedImage, imageLoader: I
 async function assetPriorityCountBelowThreshold(appRef: ApplicationRef) {
   if (IMGS_WITH_PRIORITY_ATTR_COUNT === 0) {
     IMGS_WITH_PRIORITY_ATTR_COUNT++;
-    await whenStable(appRef);
+    await appRef.whenStable();
     if (IMGS_WITH_PRIORITY_ATTR_COUNT > PRIORITY_COUNT_THRESHOLD) {
       console.warn(
         formatRuntimeError(

packages/core/src/application/application_ref.ts

@@ -915,6 +915,10 @@ let whenStableStore: WeakMap<ApplicationRef, Promise<void>> | undefined;
 /**
  * Returns a Promise that resolves when the application becomes stable after this method is called
  * the first time.
+ *
+ * Note: this function is unused in the FW code, but it's still present since the CLI code relies
+ * on it currently (see https://github.com/angular/angular-cli/blob/20411f696eb52c500e096e3dfc5e195185794edc/packages/angular/ssr/src/routes/ng-routes.ts#L435).
+ * Remove this function once CLI code is updated to use `ApplicationRef.whenStable` instead.
  */
 export function whenStable(applicationRef: ApplicationRef): Promise<void> {
   whenStableStore ??= new WeakMap();

packages/core/src/hydration/api.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import {APP_BOOTSTRAP_LISTENER, ApplicationRef, whenStable} from '../application/application_ref';
+import {APP_BOOTSTRAP_LISTENER, ApplicationRef} from '../application/application_ref';
 import {Console} from '../console';
 import {
   ENVIRONMENT_INITIALIZER,
@@ -152,7 +152,7 @@ function printHydrationStats(injector: Injector) {
  * Returns a Promise that is resolved when an application becomes stable.
  */
 function whenStableWithTimeout(appRef: ApplicationRef, injector: Injector): Promise<void> {
-  const whenStablePromise = whenStable(appRef);
+  const whenStablePromise = appRef.whenStable();
   if (typeof ngDevMode !== 'undefined' && ngDevMode) {
     const timeoutTime = APPLICATION_IS_STABLE_TIMEOUT;
     const console = injector.get(Console);

packages/core/src/hydration/event_replay.ts

@@ -18,7 +18,7 @@ import {
   EventPhase,
 } from '@angular/core/primitives/event-dispatch';
 
-import {APP_BOOTSTRAP_LISTENER, ApplicationRef, whenStable} from '../application/application_ref';
+import {APP_BOOTSTRAP_LISTENER, ApplicationRef} from '../application/application_ref';
 import {ENVIRONMENT_INITIALIZER, Injector} from '../di';
 import {inject} from '../di/injector_compatibility';
 import {Provider} from '../di/interface/provider';
@@ -134,7 +134,7 @@ export function withEventReplay(): Provider[] {
             // Kick off event replay logic once hydration for the initial part
             // of the application is completed. This timing is similar to the unclaimed
             // dehydrated views cleanup timing.
-            whenStable(appRef).then(() => {
+            appRef.whenStable().then(() => {
               const eventContractDetails = injector.get(JSACTION_EVENT_CONTRACT);
               initEventReplay(eventContractDetails, injector);
               const jsActionMap = injector.get(JSACTION_BLOCK_ELEMENT_MAP);

packages/core/test/bundling/hydration/bundle.golden_symbols.json

@@ -134,9 +134,6 @@
   {
     "name": "ElementRef"
   },
-  {
-    "name": "EmptyError"
-  },
   {
     "name": "EmulatedEncapsulationDomRenderer2"
   },
@@ -680,9 +677,6 @@
   {
     "name": "deepForEachProvider"
   },
-  {
-    "name": "defaultErrorFactory"
-  },
   {
     "name": "detachMovedView"
   },
@@ -1298,9 +1292,6 @@
   {
     "name": "subscribeOn"
   },
-  {
-    "name": "throwIfEmpty"
-  },
   {
     "name": "throwProviderNotFoundError"
   },
@@ -1337,12 +1328,6 @@
   {
     "name": "walkProviderTree"
   },
-  {
-    "name": "whenStable"
-  },
-  {
-    "name": "whenStableStore"
-  },
   {
     "name": "withDomHydration"
   },

packages/platform-server/src/utils.ts

@@ -19,7 +19,6 @@ import {
   ɵannotateForHydration as annotateForHydration,
   ɵIS_HYDRATION_DOM_REUSE_ENABLED as IS_HYDRATION_DOM_REUSE_ENABLED,
   ɵSSR_CONTENT_INTEGRITY_MARKER as SSR_CONTENT_INTEGRITY_MARKER,
-  ɵwhenStable as whenStable,
   ɵstartMeasuring as startMeasuring,
   ɵstopMeasuring as stopMeasuring,
 } from '@angular/core';
@@ -178,8 +177,10 @@ function insertEventRecordScript(
 async function _render(platformRef: PlatformRef, applicationRef: ApplicationRef): Promise<string> {
   const measuringLabel = 'whenStable';
   startMeasuring(measuringLabel);
+
   // Block until application is stable.
-  await whenStable(applicationRef);
+  await applicationRef.whenStable();
+
   stopMeasuring(measuringLabel);
 
   const platformState = platformRef.injector.get(PlatformState);