fix(core): ensure that standalone components get correct injector ins…

…tances (#50954)

Prior to this change, we've used `componentDef.id` as a key in a Map that acts as a cache to avoid re-creating injector instances for standalone components. In v16, the logic that generates the id has changed from an auto-incremental to a generation based on metadata. If multiple components have similar metadata, their ids might overlap.

This commit updates the logic to stop using `componentDef.id` as a key and instead, use the `componentDef` itself. This would ensure that we always have a correct instance of an injector associated with a standalone component instance.

Resolves #50724.

PR Close #50954

packages/core/src/render3/features/standalone_feature.ts

@@ -19,7 +19,7 @@ import {createEnvironmentInjector} from '../ng_module_ref';
  * collected from the imports graph rooted at a given standalone component.
  */
 class StandaloneService implements OnDestroy {
-  cachedInjectors = new Map<string, EnvironmentInjector|null>();
+  cachedInjectors = new Map<ComponentDef<unknown>, EnvironmentInjector|null>();
 
   constructor(private _injector: EnvironmentInjector) {}
 
@@ -28,16 +28,16 @@ class StandaloneService implements OnDestroy {
       return null;
     }
 
-    if (!this.cachedInjectors.has(componentDef.id)) {
+    if (!this.cachedInjectors.has(componentDef)) {
       const providers = internalImportProvidersFrom(false, componentDef.type);
       const standaloneInjector = providers.length > 0 ?
           createEnvironmentInjector(
               [providers], this._injector, `Standalone[${componentDef.type.name}]`) :
           null;
-      this.cachedInjectors.set(componentDef.id, standaloneInjector);
+      this.cachedInjectors.set(componentDef, standaloneInjector);
     }
 
-    return this.cachedInjectors.get(componentDef.id)!;
+    return this.cachedInjectors.get(componentDef)!;
   }
 
   ngOnDestroy() {

packages/core/test/acceptance/standalone_spec.ts

@@ -6,8 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {CommonModule} from '@angular/common';
-import {Component, createEnvironmentInjector, Directive, EnvironmentInjector, forwardRef, Injector, Input, isStandalone, NgModule, NO_ERRORS_SCHEMA, OnInit, Pipe, PipeTransform, ViewChild, ViewContainerRef} from '@angular/core';
+import {CommonModule, NgComponentOutlet} from '@angular/common';
+import {Component, createEnvironmentInjector, Directive, EnvironmentInjector, forwardRef, inject, Injectable, Injector, Input, isStandalone, NgModule, NO_ERRORS_SCHEMA, OnInit, Pipe, PipeTransform, ViewChild, ViewContainerRef} from '@angular/core';
 import {TestBed} from '@angular/core/testing';
 
 describe('standalone components, directives, and pipes', () => {
@@ -217,6 +217,69 @@ describe('standalone components, directives, and pipes', () => {
         .toEqual('Outer<inner-cmp>Inner(Service)</inner-cmp>Service');
   });
 
+  it('should correctly associate an injector with a standalone component def', () => {
+    @Injectable()
+    class MyServiceA {
+    }
+
+    @Injectable()
+    class MyServiceB {
+    }
+
+    @NgModule({
+      providers: [MyServiceA],
+    })
+    class MyModuleA {
+    }
+
+    @NgModule({
+      providers: [MyServiceB],
+    })
+    class MyModuleB {
+    }
+
+    @Component({
+      selector: 'duplicate-selector',
+      template: `ComponentA: {{ service ? 'service found' : 'service not found' }}`,
+      standalone: true,
+      imports: [MyModuleA],
+    })
+    class ComponentA {
+      service = inject(MyServiceA, {optional: true});
+    }
+
+    @Component({
+      selector: 'duplicate-selector',
+      template: `ComponentB: {{ service ? 'service found' : 'service not found' }}`,
+      standalone: true,
+      imports: [MyModuleB],
+    })
+    class ComponentB {
+      service = inject(MyServiceB, {optional: true});
+    }
+
+    @Component({
+      selector: 'app-cmp',
+      template: `
+        <ng-container [ngComponentOutlet]="ComponentA" />
+        <ng-container [ngComponentOutlet]="ComponentB" />
+      `,
+      standalone: true,
+      imports: [NgComponentOutlet],
+    })
+    class AppCmp {
+      ComponentA = ComponentA;
+      ComponentB = ComponentB;
+    }
+
+    const fixture = TestBed.createComponent(AppCmp);
+    fixture.detectChanges();
+
+    const textContent = fixture.nativeElement.textContent;
+    expect(textContent).toContain('ComponentA: service found');
+    expect(textContent).toContain('ComponentB: service found');
+  });
+
   it('should dynamically insert a standalone component', () => {
     class Service {
       value = 'Service';