fix(core): unable to NgModuleRef.injector in module constructor

packages/core/src/di/r3_injector.ts

@@ -78,8 +78,21 @@ interface Record<T> {
 export function createInjector(
     defType: /* InjectorType<any> */ any, parent: Injector | null = null,
     additionalProviders: StaticProvider[] | null = null, name?: string): Injector {
-  parent = parent || getNullInjector();
-  return new R3Injector(defType, additionalProviders, parent, name);
+  const injector =
+      createInjectorWithoutInjectorInstances(defType, parent, additionalProviders, name);
+  injector._resolveInjectorDefTypes();
+  return injector;
+}
+
+/**
+ * Creates a new injector without eagerly resolving its injector types. Can be used in places
+ * where resolving the injector types immediately can lead to an infinite loop. The injector types
+ * should be resolved at a later point by calling `_resolveInjectorDefTypes`.
+ */
+export function createInjectorWithoutInjectorInstances(
+    defType: /* InjectorType<any> */ any, parent: Injector | null = null,
+    additionalProviders: StaticProvider[] | null = null, name?: string): R3Injector {
+  return new R3Injector(defType, additionalProviders, parent || getNullInjector(), name);
 }
 
 export class R3Injector {
@@ -136,9 +149,6 @@ export class R3Injector {
     const record = this.records.get(INJECTOR_SCOPE);
     this.scope = record != null ? record.value : null;
 
-    // Eagerly instantiate the InjectorType classes themselves.
-    this.injectorDefTypes.forEach(defType => this.get(defType));
-
     // Source name, used for debugging
     this.source = source || (typeof def === 'object' ? null : stringify(def));
   }
@@ -224,6 +234,9 @@ export class R3Injector {
     }
   }
 
+  /** @internal */
+  _resolveInjectorDefTypes() { this.injectorDefTypes.forEach(defType => this.get(defType)); }
+
   toString() {
     const tokens = <string[]>[], records = this.records;
     records.forEach((v, token) => tokens.push(stringify(token)));

packages/core/src/render3/ng_module_ref.ts

@@ -9,7 +9,7 @@
 import {Injector} from '../di/injector';
 import {INJECTOR} from '../di/injector_compatibility';
 import {InjectFlags} from '../di/interface/injector';
-import {R3Injector, createInjector} from '../di/r3_injector';
+import {R3Injector, createInjectorWithoutInjectorInstances} from '../di/r3_injector';
 import {Type} from '../interface/type';
 import {ComponentFactoryResolver as viewEngine_ComponentFactoryResolver} from '../linker/component_factory_resolver';
 import {InternalNgModuleRef, NgModuleFactory as viewEngine_NgModuleFactory, NgModuleRef as viewEngine_NgModuleRef} from '../linker/ng_module_factory';
@@ -52,13 +52,18 @@ export class NgModuleRef<T> extends viewEngine_NgModuleRef<T> implements Interna
     const ngLocaleIdDef = getNgLocaleIdDef(ngModuleType);
     ngLocaleIdDef && setLocaleId(ngLocaleIdDef);
     this._bootstrapComponents = maybeUnwrapFn(ngModuleDef !.bootstrap);
-    this._r3Injector = createInjector(
+    this._r3Injector = createInjectorWithoutInjectorInstances(
         ngModuleType, _parent,
         [
           {provide: viewEngine_NgModuleRef, useValue: this},
           {provide: viewEngine_ComponentFactoryResolver, useValue: this.componentFactoryResolver}
         ],
         stringify(ngModuleType)) as R3Injector;
+
+    // We need to resolve the injector types separately from the injector creation, because
+    // the module might be trying to use this ref in its contructor for DI which will cause a
+    // circular error that will eventually error out, because the injector isn't created yet.
+    this._r3Injector._resolveInjectorDefTypes();
     this.instance = this.get(ngModuleType);
   }
 

packages/core/test/acceptance/ng_module_spec.ts

@@ -7,7 +7,7 @@
  */
 
 import {CommonModule} from '@angular/common';
-import {CUSTOM_ELEMENTS_SCHEMA, Component, ComponentFactory, Injectable, NO_ERRORS_SCHEMA, NgModule, NgModuleRef, ɵsetClassMetadata as setClassMetadata, ɵɵdefineComponent as defineComponent, ɵɵdefineInjector as defineInjector, ɵɵdefineNgModule as defineNgModule, ɵɵelement as element} from '@angular/core';
+import {CUSTOM_ELEMENTS_SCHEMA, Component, Injectable, InjectionToken, NO_ERRORS_SCHEMA, NgModule, NgModuleRef, ɵsetClassMetadata as setClassMetadata, ɵɵdefineComponent as defineComponent, ɵɵdefineInjector as defineInjector, ɵɵdefineNgModule as defineNgModule, ɵɵelement as element} from '@angular/core';
 import {TestBed} from '@angular/core/testing';
 import {expect} from '@angular/platform-browser/testing/src/matchers';
 import {modifiedInIvy, onlyInIvy} from '@angular/private/testing';
@@ -475,9 +475,28 @@ describe('NgModule', () => {
 
   });
 
-  it('should be able to use ComponentFactoryResolver from the NgModuleRef inside the module constructor',
+  it('should be able to use DI through the NgModuleRef inside the module constructor', () => {
+    const token = new InjectionToken<string>('token');
+    let value: string|undefined;
+
+    @NgModule({
+      imports: [CommonModule],
+      providers: [{provide: token, useValue: 'foo'}],
+    })
+    class TestModule {
+      constructor(ngRef: NgModuleRef<TestModule>) { value = ngRef.injector.get(token); }
+    }
+
+    TestBed.configureTestingModule({imports: [TestModule], declarations: [TestCmp]});
+    const fixture = TestBed.createComponent(TestCmp);
+    fixture.detectChanges();
+
+    expect(value).toBe('foo');
+  });
+
+  it('should be able to create a component through the ComponentFactoryResolver of an NgModuleRef in a module constructor',
      () => {
-       let factory: ComponentFactory<TestCmp>;
+       let componentInstance: TestCmp|undefined;
 
        @NgModule({
          declarations: [TestCmp],
@@ -486,13 +505,14 @@ describe('NgModule', () => {
        })
        class MyModule {
          constructor(ngModuleRef: NgModuleRef<any>) {
-           factory = ngModuleRef.componentFactoryResolver.resolveComponentFactory(TestCmp);
+           const factory = ngModuleRef.componentFactoryResolver.resolveComponentFactory(TestCmp);
+           componentInstance = factory.create(ngModuleRef.injector).instance;
          }
        }
 
        TestBed.configureTestingModule({imports: [MyModule]});
        TestBed.createComponent(TestCmp);
-       expect(factory !.componentType).toBe(TestCmp);
+       expect(componentInstance).toBeAnInstanceOf(TestCmp);
      });
 
 });

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

@@ -107,6 +107,9 @@
   {
     "name": "createInjector"
   },
+  {
+    "name": "createInjectorWithoutInjectorInstances"
+  },
   {
     "name": "deepForEach"
   },
@@ -224,4 +227,4 @@
   {
     "name": "noSideEffects"
   }
-]
+]