fix(ivy): TestBed should not clobber compilation of global-scope modules (#28033)

When an @NgModule decorator executes, the module is added to a queue in
render3/jit/module.ts. Reading an ngComponentDef property causes this queue
to be flushed, ensuring that the component gets the correct module scope
applied.

In before_each.ts, a global beforeEach is added to all Angular tests which
calls TestBed.resetTestingModule() prior to running each test. This in turn
clears the module compilation queue (which is correct behavior, as modules
declared within the test should not leak outside of it via the queue).

So far this is okay. But before the first test runs, the module compilation
queue is full of modules declared in global scope. No definitions have been
read, so no flushes of the queue have been triggered. The global beforeEach
triggers a reset of the queue, aborting all of the in-progress global
compilation, breaking those classes when they're later used in tests.

This commit adds logic to TestBedRender3 to respect the state of the module
queue before the TestBed is first initialized or reset. The queue is flushed
prior to such an operation to ensure global compilation is allowed to finish
properly.

With this fix, a platform-server test now passes (previously the <my-child>
element was not detected as a component, because the encompassing module
never finished compilation.

FW-887 #resolve

PR Close #28033

packages/core/src/core_render3_private_export.ts

@@ -135,6 +135,7 @@ export {
   compileNgModuleDefs as ɵcompileNgModuleDefs,
   patchComponentDefWithScope as ɵpatchComponentDefWithScope,
   resetCompiledComponents as ɵresetCompiledComponents,
+  flushModuleScopingQueueAsMuchAsPossible as ɵflushModuleScopingQueueAsMuchAsPossible,
   transitiveScopesFor as ɵtransitiveScopesFor,
 } from './render3/jit/module';
 export {

packages/core/testing/src/r3_test_bed.ts

@@ -43,6 +43,7 @@ import {
   ɵcompileNgModuleDefs as compileNgModuleDefs,
   ɵcompilePipe as compilePipe,
   ɵgetInjectableDef as getInjectableDef,
+  ɵflushModuleScopingQueueAsMuchAsPossible as flushModuleScopingQueueAsMuchAsPossible,
   ɵpatchComponentDefWithScope as patchComponentDefWithScope,
   ɵresetCompiledComponents as resetCompiledComponents,
   ɵstringify as stringify, ɵtransitiveScopesFor as transitiveScopesFor,
@@ -245,6 +246,7 @@ export class TestBedRender3 implements Injector, TestBed {
   private _testModuleType: NgModuleType<any> = null !;
 
   private _instantiated: boolean = false;
+  private _globalCompilationChecked = false;
 
   // Map that keeps initial version of component/directive/pipe defs in case
   // we compile a Type again, thus overriding respective static fields. This is
@@ -285,6 +287,7 @@ export class TestBedRender3 implements Injector, TestBed {
   }
 
   resetTestingModule(): void {
+    this._checkGlobalCompilationFinished();
     resetCompiledComponents();
     // reset metadata overrides
     this._moduleOverrides = [];
@@ -459,6 +462,7 @@ export class TestBedRender3 implements Injector, TestBed {
   // internal methods
 
   private _initIfNeeded(): void {
+    this._checkGlobalCompilationFinished();
     if (this._instantiated) {
       return;
     }
@@ -626,6 +630,27 @@ export class TestBedRender3 implements Injector, TestBed {
       patchComponentDefWithScope((cmp as any).ngComponentDef, scope);
     });
   }
+
+  /**
+   * Check whether the module scoping queue should be flushed, and flush it if needed.
+   *
+   * When the TestBed is reset, it clears the JIT module compilation queue, cancelling any
+   * in-progress module compilation. This creates a potential hazard - the very first time the
+   * TestBed is initialized (or if it's reset without being initialized), there may be pending
+   * compilations of modules declared in global scope. These compilations should be finished.
+   *
+   * To ensure that globally declared modules have their components scoped properly, this function
+   * is called whenever TestBed is initialized or reset. The _first_ time that this happens, prior
+   * to any other operations, the scoping queue is flushed.
+   */
+  private _checkGlobalCompilationFinished(): void {
+    // !this._instantiated should not be necessary, but is left in as an additional guard that
+    // compilations queued in tests (after instantiation) are never flushed accidentally.
+    if (!this._globalCompilationChecked && !this._instantiated) {
+      flushModuleScopingQueueAsMuchAsPossible();
+    }
+    this._globalCompilationChecked = true;
+  }
 }
 
 let testBed: TestBedRender3;

packages/platform-server/test/integration_spec.ts

@@ -617,15 +617,14 @@ class HiddenModule {
            });
          }));
 
-      fixmeIvy('FW-887: JIT: compilation of NgModule')
-          .it('should handle false values on attributes', async(() => {
-                renderModule(FalseAttributesModule, {document: doc}).then(output => {
-                  expect(output).toBe(
-                      '<html><head></head><body><app ng-version="0.0.0-PLACEHOLDER">' +
-                      '<my-child ng-reflect-attr="false">Works!</my-child></app></body></html>');
-                  called = true;
-                });
-              }));
+      it('should handle false values on attributes', async(() => {
+           renderModule(FalseAttributesModule, {document: doc}).then(output => {
+             expect(output).toBe(
+                 '<html><head></head><body><app ng-version="0.0.0-PLACEHOLDER">' +
+                 '<my-child ng-reflect-attr="false">Works!</my-child></app></body></html>');
+             called = true;
+           });
+         }));
 
       it('should handle element property "name"', async(() => {
            renderModule(NameModule, {document: doc}).then(output => {