From 7b27009e20c6a0eec3d3debfc967768284f1cf21 Mon Sep 17 00:00:00 2001
From: Alex Rickabaugh <alx+alxhub@alxandria.net>
Date: Thu, 28 Mar 2019 10:48:29 -0700
Subject: [PATCH] fix(ivy): fix proliferation of provider overrides for modules
 (#29571)

When an @NgModule is imported more than once in the testing module (for
example it appears in the imports of more than one module, or if it's
literally listed multiple times), then TestBed had a bug where the
providers for the module would be overridden many times.

This alone was problematic but would not break tests. However, the original
value of the providers field of the ngInjectorDef was saved each time, and
restored in the same order. Thus, if the provider array was [X], and
overrides were applied twice, then the override array would become
[X, X'] and then [X, X', X, X']. However, on the second override the state
[X, X'] would be stored as original. The array would then be restored to
[X] and then [X, X'].

Each test, therefore, would continue to double the size of the providers
array for the module, eventually exhausting the browser's memory.

This commit adds a Set to track when overrides have been applied to a module
and refrain from applying them more than once.

PR Close #29571
---
 packages/core/test/test_bed_spec.ts           | 28 ++++++++++++++++++-
 .../core/testing/src/r3_test_bed_compiler.ts  |  7 +++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/packages/core/test/test_bed_spec.ts b/packages/core/test/test_bed_spec.ts
index 6ef190b3f8..ac989deb5b 100644
--- a/packages/core/test/test_bed_spec.ts
+++ b/packages/core/test/test_bed_spec.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Component, Directive, ErrorHandler, Inject, InjectionToken, NgModule, Optional, Pipe, ɵdefineComponent as defineComponent, ɵsetClassMetadata as setClassMetadata, ɵtext as text} from '@angular/core';
+import {Component, Directive, ErrorHandler, Inject, Injectable, InjectionToken, NgModule, Optional, Pipe, ɵdefineComponent as defineComponent, ɵsetClassMetadata as setClassMetadata, ɵtext as text} from '@angular/core';
 import {TestBed, getTestBed} from '@angular/core/testing/src/test_bed';
 import {By} from '@angular/platform-browser';
 import {expect} from '@angular/platform-browser/testing/src/matchers';
@@ -413,5 +413,31 @@ describe('TestBed', () => {
              expect(SomeDirective.hasOwnProperty('ngDirectiveDef')).toBeTruthy();
              expect(SomePipe.hasOwnProperty('ngPipeDef')).toBeTruthy();
            });
+
+        it('should clean up overridden providers for modules that are imported more than once',
+           () => {
+
+             @Injectable()
+             class Token {
+               name: string = 'real';
+             }
+
+             @NgModule({
+               providers: [Token],
+             })
+             class Module {
+             }
+
+             TestBed.configureTestingModule({imports: [Module, Module]});
+             TestBed.overrideProvider(Token, {useValue: {name: 'fake'}});
+
+             expect(TestBed.get(Token).name).toEqual('fake');
+
+             TestBed.resetTestingModule();
+
+             // The providers for the module should have been restored to the original array, with
+             // no trace of the overridden providers.
+             expect((Module as any).ngInjectorDef.providers).toEqual([Token]);
+           });
       });
 });
diff --git a/packages/core/testing/src/r3_test_bed_compiler.ts b/packages/core/testing/src/r3_test_bed_compiler.ts
index c2e38deb3d..3a607f5851 100644
--- a/packages/core/testing/src/r3_test_bed_compiler.ts
+++ b/packages/core/testing/src/r3_test_bed_compiler.ts
@@ -111,6 +111,7 @@ export class R3TestBedCompiler {
   private providerOverrides: Provider[] = [];
   private rootProviderOverrides: Provider[] = [];
   private providerOverridesByToken = new Map<any, Provider[]>();
+  private moduleProvidersOverridden = new Set<Type<any>>();
 
   private testModuleType: NgModuleType<any>;
   private testModuleRef: NgModuleRef<any>|null = null;
@@ -374,6 +375,11 @@ export class R3TestBedCompiler {
   }
 
   private applyProviderOverridesToModule(moduleType: Type<any>): void {
+    if (this.moduleProvidersOverridden.has(moduleType)) {
+      return;
+    }
+    this.moduleProvidersOverridden.add(moduleType);
+
     const injectorDef: any = (moduleType as any)[NG_INJECTOR_DEF];
     if (this.providerOverridesByToken.size > 0) {
       if (this.hasProviderOverrides(injectorDef.providers)) {
@@ -530,6 +536,7 @@ export class R3TestBedCompiler {
       }
     });
     this.initialNgDefs.clear();
+    this.moduleProvidersOverridden.clear();
     this.restoreComponentResolutionQueue();
   }