fix(animations): Trigger leave animation when ViewContainerRef is injected (#48705)

Injecting `ViewContainerRef` into a component makes it effectively a container. The leave animation wasn't triggered on containers before this fix.

fixes angular#48667

PR Close #48705

packages/animations/browser/src/render/animation_engine_next.ts

@@ -72,8 +72,8 @@ export class AnimationEngine {
     this._transitionEngine.insertNode(namespaceId, element, parent, insertBefore);
   }
 
-  onRemove(namespaceId: string, element: any, context: any, isHostElement?: boolean): void {
-    this._transitionEngine.removeNode(namespaceId, element, isHostElement || false, context);
+  onRemove(namespaceId: string, element: any, context: any): void {
+    this._transitionEngine.removeNode(namespaceId, element, context);
   }
 
   disableAnimations(element: any, disable: boolean) {

packages/animations/browser/src/render/transition_animation_engine.ts

@@ -744,7 +744,7 @@ export class TransitionAnimationEngine {
     }
   }
 
-  removeNode(namespaceId: string, element: any, isHostElement: boolean, context: any): void {
+  removeNode(namespaceId: string, element: any, context: any): void {
     if (isElementNode(element)) {
       const ns = namespaceId ? this._fetchNamespace(namespaceId) : null;
       if (ns) {
@@ -753,11 +753,9 @@ export class TransitionAnimationEngine {
         this.markElementAsRemoved(namespaceId, element, false, context);
       }
 
-      if (isHostElement) {
-        const hostNS = this.namespacesByHostElement.get(element);
-        if (hostNS && hostNS.id !== namespaceId) {
-          hostNS.removeNode(element, context);
-        }
+      const hostNS = this.namespacesByHostElement.get(element);
+      if (hostNS && hostNS.id !== namespaceId) {
+        hostNS.removeNode(element, context);
       }
     } else {
       this._onRemovalComplete(element, context);

packages/animations/browser/test/render/transition_animation_engine_spec.ts

@@ -116,7 +116,7 @@ describe('TransitionAnimationEngine', () => {
 
       expect(engine.elementContainsData(DEFAULT_NAMESPACE_ID, element)).toBeTruthy();
 
-      engine.removeNode(DEFAULT_NAMESPACE_ID, element, true, true);
+      engine.removeNode(DEFAULT_NAMESPACE_ID, element, true);
       engine.flush();
 
       expect(engine.elementContainsData(DEFAULT_NAMESPACE_ID, element)).toBeTruthy();
@@ -171,7 +171,7 @@ describe('TransitionAnimationEngine', () => {
       expect(engine.statesByElement.has(element)).toBe(true, 'Expected parent data to be defined.');
       expect(engine.statesByElement.has(child)).toBe(true, 'Expected child data to be defined.');
 
-      engine.removeNode(DEFAULT_NAMESPACE_ID, element, true, true);
+      engine.removeNode(DEFAULT_NAMESPACE_ID, element, true);
       engine.flush();
       engine.players[0].finish();
 

packages/core/test/animation/animation_integration_spec.ts

@@ -8,7 +8,7 @@
 import {animate, animateChild, animation, AnimationEvent, AnimationMetadata, AnimationOptions, AUTO_STYLE, group, keyframes, query, sequence, state, style, transition, trigger, useAnimation, ɵPRE_STYLE as PRE_STYLE} from '@angular/animations';
 import {AnimationDriver, ɵAnimationEngine, ɵNoopAnimationDriver as NoopAnimationDriver} from '@angular/animations/browser';
 import {MockAnimationDriver, MockAnimationPlayer} from '@angular/animations/browser/testing';
-import {ChangeDetectorRef, Component, HostBinding, HostListener, Inject, RendererFactory2, ViewChild} from '@angular/core';
+import {ChangeDetectorRef, Component, HostBinding, HostListener, Inject, RendererFactory2, ViewChild, ViewContainerRef} from '@angular/core';
 import {fakeAsync, flushMicrotasks, TestBed} from '@angular/core/testing';
 import {ɵDomRendererFactory2} from '@angular/platform-browser';
 import {ANIMATION_MODULE_TYPE, BrowserAnimationsModule, NoopAnimationsModule} from '@angular/platform-browser/animations';
@@ -909,6 +909,56 @@ describe('animation tests', function() {
            ]);
          }));
 
+      it('should trigger a leave animation when the inner has ViewContainerRef injected',
+         fakeAsync(() => {
+           @Component({
+             selector: 'parent-cmp',
+             template: `
+             <child-cmp *ngIf="exp"></child-cmp>
+           `
+           })
+           class ParentCmp {
+             public exp = true;
+           }
+
+           @Component({
+             selector: 'child-cmp',
+             template: '...',
+             animations: [trigger(
+                 'host',
+                 [transition(':leave', [style({opacity: 1}), animate(1000, style({opacity: 0}))])])]
+           })
+           class ChildCmp {
+             @HostBinding('@host') public hostAnimation = true;
+             constructor(private vcr: ViewContainerRef) {}
+           }
+
+           TestBed.configureTestingModule({declarations: [ParentCmp, ChildCmp]});
+
+           const engine = TestBed.inject(ɵAnimationEngine);
+           const fixture = TestBed.createComponent(ParentCmp);
+           const cmp = fixture.componentInstance;
+           fixture.detectChanges();
+           engine.flush();
+           expect(getLog().length).toEqual(0);
+
+           cmp.exp = false;
+           fixture.detectChanges();
+           expect(fixture.debugElement.nativeElement.children.length).toBe(1);
+
+           engine.flush();
+           expect(getLog().length).toEqual(1);
+
+           const [player] = getLog();
+           expect(player.keyframes).toEqual([
+             new Map<string, string|number>([['opacity', '1'], ['offset', 0]]),
+             new Map<string, string|number>([['opacity', '0'], ['offset', 1]]),
+           ]);
+
+           player.finish();
+           expect(fixture.debugElement.nativeElement.children.length).toBe(0);
+         }));
+
       it('should trigger a leave animation when the inner components host binding updates',
          fakeAsync(() => {
            @Component({

packages/platform-browser/animations/src/animation_renderer.ts

@@ -180,7 +180,7 @@ export class BaseAnimationRenderer implements Renderer2 {
   }
 
   removeChild(parent: any, oldChild: any, isHostElement: boolean): void {
-    this.engine.onRemove(this.namespaceId, oldChild, this.delegate, isHostElement);
+    this.engine.onRemove(this.namespaceId, oldChild, this.delegate);
   }
 
   selectRootElement(selectorOrNode: any, preserveContent?: boolean) {