fix(ivy): properly compile NgModules with forward referenced types (#29198)

Previously, ngtsc would resolve forward references while evaluating the
bootstrap, declaration, imports, and exports fields of NgModule types.
However, when generating the resulting ngModuleDef, the forward nature of
these references was not taken into consideration, and so the generated JS
code would incorrectly reference types not yet declared.

This commit fixes this issue by introducing function closures in the
NgModuleDef type, similarly to how NgComponentDef uses them for forward
declarations of its directives and pipes arrays. ngtsc will then generate
closures when required, and the runtime will unwrap them if present.

PR Close #29198

packages/compiler-cli/src/ngtsc/annotations/src/component.ts

@@ -23,7 +23,7 @@ import {tsSourceMapBug29300Fixed} from '../../util/src/ts_source_map_bug_29300';
 import {ResourceLoader} from './api';
 import {extractDirectiveMetadata, extractQueriesFromDecorator, parseFieldArrayValue, queriesFromFields} from './directive';
 import {generateSetClassMetadataCall} from './metadata';
-import {findAngularDecorator, isAngularCoreReference, unwrapExpression} from './util';
+import {findAngularDecorator, isAngularCoreReference, isExpressionForwardReference, unwrapExpression} from './util';
 
 const EMPTY_MAP = new Map<string, Expression>();
 const EMPTY_ARRAY: any[] = [];
@@ -616,20 +616,6 @@ function getTemplateRange(templateExpr: ts.Expression) {
   };
 }
 
-function isExpressionForwardReference(
-    expr: Expression, context: ts.Node, contextSource: ts.SourceFile): boolean {
-  if (isWrappedTsNodeExpr(expr)) {
-    const node = ts.getOriginalNode(expr.node);
-    return node.getSourceFile() === contextSource && context.pos < node.pos;
-  } else {
-    return false;
-  }
-}
-
-function isWrappedTsNodeExpr(expr: Expression): expr is WrappedNodeExpr<ts.Node> {
-  return expr instanceof WrappedNodeExpr;
-}
-
 function sourceMapUrl(resourceUrl: string): string {
   if (!tsSourceMapBug29300Fixed()) {
     // By removing the template URL we are telling the translator not to try to

packages/compiler-cli/src/ngtsc/annotations/src/ng_module.ts

@@ -20,7 +20,7 @@ import {getSourceFile} from '../../util/src/typescript';
 
 import {generateSetClassMetadataCall} from './metadata';
 import {ReferencesRegistry} from './references_registry';
-import {combineResolvers, findAngularDecorator, forwardRefResolver, getValidConstructorDependencies, toR3Reference, unwrapExpression} from './util';
+import {combineResolvers, findAngularDecorator, forwardRefResolver, getValidConstructorDependencies, isExpressionForwardReference, toR3Reference, unwrapExpression} from './util';
 
 export interface NgModuleAnalysis {
   ngModuleDef: R3NgModuleMetadata;
@@ -90,38 +90,39 @@ export class NgModuleDecoratorHandler implements DecoratorHandler<NgModuleAnalys
     ]);
 
     // Extract the module declarations, imports, and exports.
-    let declarations: Reference<ts.Declaration>[] = [];
+    let declarationRefs: Reference<ts.Declaration>[] = [];
     if (ngModule.has('declarations')) {
       const expr = ngModule.get('declarations') !;
       const declarationMeta = this.evaluator.evaluate(expr, forwardRefResolver);
-      declarations = this.resolveTypeList(expr, declarationMeta, name, 'declarations');
+      declarationRefs = this.resolveTypeList(expr, declarationMeta, name, 'declarations');
     }
-    let imports: Reference<ts.Declaration>[] = [];
+    let importRefs: Reference<ts.Declaration>[] = [];
     let rawImports: ts.Expression|null = null;
     if (ngModule.has('imports')) {
       rawImports = ngModule.get('imports') !;
       const importsMeta = this.evaluator.evaluate(rawImports, moduleResolvers);
-      imports = this.resolveTypeList(rawImports, importsMeta, name, 'imports');
+      importRefs = this.resolveTypeList(rawImports, importsMeta, name, 'imports');
     }
-    let exports: Reference<ts.Declaration>[] = [];
+    let exportRefs: Reference<ts.Declaration>[] = [];
     let rawExports: ts.Expression|null = null;
     if (ngModule.has('exports')) {
       rawExports = ngModule.get('exports') !;
       const exportsMeta = this.evaluator.evaluate(rawExports, moduleResolvers);
-      exports = this.resolveTypeList(rawExports, exportsMeta, name, 'exports');
-      this.referencesRegistry.add(node, ...exports);
+      exportRefs = this.resolveTypeList(rawExports, exportsMeta, name, 'exports');
+      this.referencesRegistry.add(node, ...exportRefs);
     }
-    let bootstrap: Reference<ts.Declaration>[] = [];
+    let bootstrapRefs: Reference<ts.Declaration>[] = [];
     if (ngModule.has('bootstrap')) {
       const expr = ngModule.get('bootstrap') !;
       const bootstrapMeta = this.evaluator.evaluate(expr, forwardRefResolver);
-      bootstrap = this.resolveTypeList(expr, bootstrapMeta, name, 'bootstrap');
+      bootstrapRefs = this.resolveTypeList(expr, bootstrapMeta, name, 'bootstrap');
     }
 
     // Register this module's information with the LocalModuleScopeRegistry. This ensures that
     // during the compile() phase, the module's metadata is available for selector scope
     // computation.
-    this.scopeRegistry.registerNgModule(node, {declarations, imports, exports});
+    this.scopeRegistry.registerNgModule(
+        node, {declarations: declarationRefs, imports: importRefs, exports: exportRefs});
 
     const valueContext = node.getSourceFile();
 
@@ -131,13 +132,26 @@ export class NgModuleDecoratorHandler implements DecoratorHandler<NgModuleAnalys
       typeContext = typeNode.getSourceFile();
     }
 
+    const bootstrap =
+        bootstrapRefs.map(bootstrap => this._toR3Reference(bootstrap, valueContext, typeContext));
+    const declarations =
+        declarationRefs.map(decl => this._toR3Reference(decl, valueContext, typeContext));
+    const imports = importRefs.map(imp => this._toR3Reference(imp, valueContext, typeContext));
+    const exports = exportRefs.map(exp => this._toR3Reference(exp, valueContext, typeContext));
+
+    const isForwardReference = (ref: R3Reference) =>
+        isExpressionForwardReference(ref.value, node.name !, valueContext);
+    const containsForwardDecls = bootstrap.some(isForwardReference) ||
+        declarations.some(isForwardReference) || imports.some(isForwardReference) ||
+        exports.some(isForwardReference);
+
     const ngModuleDef: R3NgModuleMetadata = {
       type: new WrappedNodeExpr(node.name !),
-      bootstrap:
-          bootstrap.map(bootstrap => this._toR3Reference(bootstrap, valueContext, typeContext)),
-      declarations: declarations.map(decl => this._toR3Reference(decl, valueContext, typeContext)),
-      exports: exports.map(exp => this._toR3Reference(exp, valueContext, typeContext)),
-      imports: imports.map(imp => this._toR3Reference(imp, valueContext, typeContext)),
+      bootstrap,
+      declarations,
+      exports,
+      imports,
+      containsForwardDecls,
       emitInline: false,
       // TODO: to be implemented as a part of FW-1004.
       schemas: [],
@@ -173,7 +187,7 @@ export class NgModuleDecoratorHandler implements DecoratorHandler<NgModuleAnalys
       analysis: {
         ngModuleDef,
         ngInjectorDef,
-        declarations,
+        declarations: declarationRefs,
         metadataStmt: generateSetClassMetadataCall(
             node, this.reflector, this.defaultImportRecorder, this.isCore),
       },

packages/compiler-cli/src/ngtsc/annotations/src/util.ts

@@ -278,3 +278,17 @@ export function combineResolvers(resolvers: ForeignFunctionResolver[]): ForeignF
     return null;
   };
 }
+
+export function isExpressionForwardReference(
+    expr: Expression, context: ts.Node, contextSource: ts.SourceFile): boolean {
+  if (isWrappedTsNodeExpr(expr)) {
+    const node = ts.getOriginalNode(expr.node);
+    return node.getSourceFile() === contextSource && context.pos < node.pos;
+  } else {
+    return false;
+  }
+}
+
+export function isWrappedTsNodeExpr(expr: Expression): expr is WrappedNodeExpr<ts.Node> {
+  return expr instanceof WrappedNodeExpr;
+}

packages/compiler-cli/test/ngtsc/ngtsc_spec.ts

@@ -643,6 +643,86 @@ describe('ngtsc behavioral tests', () => {
     expect(dtsContents).toContain('as i1 from "foo";');
   });
 
+  it('should compile NgModules with references to forward declared bootstrap components', () => {
+    env.tsconfig();
+    env.write('test.ts', `
+      import {Component, forwardRef, NgModule} from '@angular/core';
+
+      @NgModule({
+        bootstrap: [forwardRef(() => Foo)],
+      })
+      export class FooModule {}
+
+      @Component({selector: 'foo', template: 'foo'})
+      export class Foo {}
+    `);
+
+    env.driveMain();
+
+    const jsContents = env.getContents('test.js');
+    expect(jsContents).toContain('bootstrap: function () { return [Foo]; }');
+  });
+
+  it('should compile NgModules with references to forward declared directives', () => {
+    env.tsconfig();
+    env.write('test.ts', `
+      import {Directive, forwardRef, NgModule} from '@angular/core';
+
+      @NgModule({
+        declarations: [forwardRef(() => Foo)],
+      })
+      export class FooModule {}
+
+      @Directive({selector: 'foo'})
+      export class Foo {}
+    `);
+
+    env.driveMain();
+
+    const jsContents = env.getContents('test.js');
+    expect(jsContents).toContain('declarations: function () { return [Foo]; }');
+  });
+
+  it('should compile NgModules with references to forward declared imports', () => {
+    env.tsconfig();
+    env.write('test.ts', `
+      import {forwardRef, NgModule} from '@angular/core';
+
+      @NgModule({
+        imports: [forwardRef(() => BarModule)],
+      })
+      export class FooModule {}
+
+      @NgModule({})
+      export class BarModule {}
+    `);
+
+    env.driveMain();
+
+    const jsContents = env.getContents('test.js');
+    expect(jsContents).toContain('imports: function () { return [BarModule]; }');
+  });
+
+  it('should compile NgModules with references to forward declared exports', () => {
+    env.tsconfig();
+    env.write('test.ts', `
+      import {forwardRef, NgModule} from '@angular/core';
+
+      @NgModule({
+        exports: [forwardRef(() => BarModule)],
+      })
+      export class FooModule {}
+
+      @NgModule({})
+      export class BarModule {}
+    `);
+
+    env.driveMain();
+
+    const jsContents = env.getContents('test.js');
+    expect(jsContents).toContain('exports: function () { return [BarModule]; }');
+  });
+
   it('should compile Pipes without errors', () => {
     env.tsconfig();
     env.write('test.ts', `

packages/compiler/src/jit_compiler_facade.ts

@@ -88,6 +88,7 @@ export class CompilerFacadeImpl implements CompilerFacade {
       imports: facade.imports.map(wrapReference),
       exports: facade.exports.map(wrapReference),
       emitInline: true,
+      containsForwardDecls: false,
       schemas: facade.schemas ? facade.schemas.map(wrapReference) : null,
     };
     const res = compileNgModule(meta);

packages/compiler/src/render3/r3_module_compiler.ts

@@ -58,6 +58,11 @@ export interface R3NgModuleMetadata {
    */
   emitInline: boolean;
 
+  /**
+   * Whether to generate closure wrappers for bootstrap, declarations, imports, and exports.
+   */
+  containsForwardDecls: boolean;
+
   /**
    * The set of schemas that declare elements to be allowed in the NgModule.
    */
@@ -68,33 +73,42 @@ export interface R3NgModuleMetadata {
  * Construct an `R3NgModuleDef` for the given `R3NgModuleMetadata`.
  */
 export function compileNgModule(meta: R3NgModuleMetadata): R3NgModuleDef {
-  const {type: moduleType, bootstrap, declarations, imports, exports, schemas} = meta;
+  const {
+    type: moduleType,
+    bootstrap,
+    declarations,
+    imports,
+    exports,
+    schemas,
+    containsForwardDecls
+  } = meta;
+
   const definitionMap = {
     type: moduleType
   } as{
     type: o.Expression,
-    bootstrap: o.LiteralArrayExpr,
-    declarations: o.LiteralArrayExpr,
-    imports: o.LiteralArrayExpr,
-    exports: o.LiteralArrayExpr,
+    bootstrap: o.Expression,
+    declarations: o.Expression,
+    imports: o.Expression,
+    exports: o.Expression,
     schemas: o.LiteralArrayExpr
   };
 
   // Only generate the keys in the metadata if the arrays have values.
   if (bootstrap.length) {
-    definitionMap.bootstrap = o.literalArr(bootstrap.map(ref => ref.value));
+    definitionMap.bootstrap = refsToArray(bootstrap, containsForwardDecls);
   }
 
   if (declarations.length) {
-    definitionMap.declarations = o.literalArr(declarations.map(ref => ref.value));
+    definitionMap.declarations = refsToArray(declarations, containsForwardDecls);
   }
 
   if (imports.length) {
-    definitionMap.imports = o.literalArr(imports.map(ref => ref.value));
+    definitionMap.imports = refsToArray(imports, containsForwardDecls);
   }
 
   if (exports.length) {
-    definitionMap.exports = o.literalArr(exports.map(ref => ref.value));
+    definitionMap.exports = refsToArray(exports, containsForwardDecls);
   }
 
   if (schemas && schemas.length) {
@@ -182,3 +196,8 @@ function tupleTypeOf(exp: R3Reference[]): o.Type {
   const types = exp.map(ref => o.typeofExpr(ref.type));
   return exp.length > 0 ? o.expressionType(o.literalArr(types)) : o.NONE_TYPE;
 }
+
+function refsToArray(refs: R3Reference[], shouldForwardDeclare: boolean): o.Expression {
+  const values = o.literalArr(refs.map(ref => ref.value));
+  return shouldForwardDeclare ? o.fn([], [new o.ReturnStatement(values)]) : values;
+}

packages/core/src/linker/compiler.ts

@@ -15,6 +15,7 @@ import {ViewEncapsulation} from '../metadata';
 import {ComponentFactory as ComponentFactoryR3} from '../render3/component_ref';
 import {getComponentDef, getNgModuleDef} from '../render3/definition';
 import {NgModuleFactory as NgModuleFactoryR3} from '../render3/ng_module_ref';
+import {maybeUnwrapFn} from '../render3/util/misc_utils';
 
 import {ComponentFactory} from './component_factory';
 import {NgModuleFactory} from './ng_module_factory';
@@ -60,7 +61,9 @@ export const Compiler_compileModuleAndAllComponentsSync__POST_R3__: <T>(moduleTy
         ModuleWithComponentFactories<T> {
   const ngModuleFactory = Compiler_compileModuleSync__POST_R3__(moduleType);
   const moduleDef = getNgModuleDef(moduleType) !;
-  const componentFactories = moduleDef.declarations.reduce((factories, declaration) => {
+  const componentFactories =
+      maybeUnwrapFn(moduleDef.declarations)
+          .reduce((factories: ComponentFactory<any>[], declaration: Type<any>) => {
             const componentDef = getComponentDef(declaration);
             componentDef && factories.push(new ComponentFactoryR3(componentDef));
             return factories;

packages/core/src/metadata/ng_module.ts

@@ -49,19 +49,19 @@ export interface NgModuleDef<T> {
   type: T;
 
   /** List of components to bootstrap. */
-  bootstrap: Type<any>[];
+  bootstrap: Type<any>[]|(() => Type<any>[]);
 
   /** List of components, directives, and pipes declared by this module. */
-  declarations: Type<any>[];
+  declarations: Type<any>[]|(() => Type<any>[]);
 
   /** List of modules or `ModuleWithProviders` imported by this module. */
-  imports: Type<any>[];
+  imports: Type<any>[]|(() => Type<any>[]);
 
   /**
    * List of modules, `ModuleWithProviders`, components, directives, or pipes exported by this
    * module.
    */
-  exports: Type<any>[];
+  exports: Type<any>[]|(() => Type<any>[]);
 
   /**
    * Cached value of computed `transitiveCompileScopes` for this module.

packages/core/src/render3/jit/module.ts

@@ -19,7 +19,7 @@ import {getComponentDef, getDirectiveDef, getNgModuleDef, getPipeDef} from '../d
 import {NG_COMPONENT_DEF, NG_DIRECTIVE_DEF, NG_MODULE_DEF, NG_PIPE_DEF} from '../fields';
 import {ComponentDef} from '../interfaces/definition';
 import {NgModuleType} from '../ng_module_ref';
-import {renderStringify} from '../util/misc_utils';
+import {maybeUnwrapFn, renderStringify} from '../util/misc_utils';
 
 import {angularCoreEnv} from './environment';
 
@@ -156,14 +156,17 @@ function verifySemanticsOfNgModuleDef(moduleType: NgModuleType): void {
   moduleType = resolveForwardRef(moduleType);
   const ngModuleDef = getNgModuleDef(moduleType, true);
   const errors: string[] = [];
-  ngModuleDef.declarations.forEach(verifyDeclarationsHaveDefinitions);
+  const declarations = maybeUnwrapFn(ngModuleDef.declarations);
+  const imports = maybeUnwrapFn(ngModuleDef.imports);
+  const exports = maybeUnwrapFn(ngModuleDef.exports);
+  declarations.forEach(verifyDeclarationsHaveDefinitions);
   const combinedDeclarations: Type<any>[] = [
-    ...ngModuleDef.declarations.map(resolveForwardRef),  //
-    ...flatten(ngModuleDef.imports.map(computeCombinedExports), resolveForwardRef),
+    ...declarations.map(resolveForwardRef),  //
+    ...flatten(imports.map(computeCombinedExports), resolveForwardRef),
   ];
-  ngModuleDef.exports.forEach(verifyExportsAreDeclaredOrReExported);
-  ngModuleDef.declarations.forEach(verifyDeclarationIsUnique);
-  ngModuleDef.declarations.forEach(verifyComponentEntryComponentsIsPartOfNgModule);
+  exports.forEach(verifyExportsAreDeclaredOrReExported);
+  declarations.forEach(verifyDeclarationIsUnique);
+  declarations.forEach(verifyComponentEntryComponentsIsPartOfNgModule);
 
   const ngModule = getAnnotation<NgModule>(moduleType, 'NgModule');
   if (ngModule) {
@@ -297,15 +300,14 @@ export function resetCompiledComponents(): void {
 }
 
 /**
- * Computes the combined declarations of explicit declarations, as well as declarations inherited
- * by
+ * Computes the combined declarations of explicit declarations, as well as declarations inherited by
  * traversing the exports of imported modules.
  * @param type
  */
 function computeCombinedExports(type: Type<any>): Type<any>[] {
   type = resolveForwardRef(type);
   const ngModuleDef = getNgModuleDef(type, true);
-  return [...flatten(ngModuleDef.exports.map((type) => {
+  return [...flatten(maybeUnwrapFn(ngModuleDef.exports).map((type) => {
     const ngModuleDef = getNgModuleDef(type);
     if (ngModuleDef) {
       verifySemanticsOfNgModuleDef(type as any as NgModuleType);
@@ -388,7 +390,7 @@ export function transitiveScopesFor<T>(
     },
   };
 
-  def.declarations.forEach(declared => {
+  maybeUnwrapFn(def.declarations).forEach(declared => {
     const declaredWithDefs = declared as Type<any>& { ngPipeDef?: any; };
 
     if (getPipeDef(declaredWithDefs)) {
@@ -401,7 +403,7 @@ export function transitiveScopesFor<T>(
     }
   });
 
-  def.imports.forEach(<I>(imported: Type<I>) => {
+  maybeUnwrapFn(def.imports).forEach(<I>(imported: Type<I>) => {
     const importedType = imported as Type<I>& {
       // If imported is an @NgModule:
       ngModuleDef?: NgModuleDef<I>;
@@ -422,7 +424,7 @@ export function transitiveScopesFor<T>(
     importedScope.exported.pipes.forEach(entry => scopes.compilation.pipes.add(entry));
   });
 
-  def.exports.forEach(<E>(exported: Type<E>) => {
+  maybeUnwrapFn(def.exports).forEach(<E>(exported: Type<E>) => {
     const exportedType = exported as Type<E>& {
       // Components, Directives, NgModules, and Pipes can all be exported.
       ngComponentDef?: any;

packages/core/src/render3/ng_module_ref.ts

@@ -18,6 +18,7 @@ import {assertDefined} from '../util/assert';
 import {stringify} from '../util/stringify';
 import {ComponentFactoryResolver} from './component_ref';
 import {getNgModuleDef} from './definition';
+import {maybeUnwrapFn} from './util/misc_utils';
 
 export interface NgModuleType<T = any> extends Type<T> { ngModuleDef: NgModuleDef<T>; }
 
@@ -43,7 +44,7 @@ export class NgModuleRef<T> extends viewEngine_NgModuleRef<T> implements Interna
                      ngModuleDef,
                      `NgModule '${stringify(ngModuleType)}' is not a subtype of 'NgModuleType'.`);
 
-    this._bootstrapComponents = ngModuleDef !.bootstrap;
+    this._bootstrapComponents = maybeUnwrapFn(ngModuleDef !.bootstrap);
     const additionalProviders: StaticProvider[] = [
       {
         provide: viewEngine_NgModuleRef,

packages/core/src/render3/util/misc_utils.ts

@@ -76,3 +76,14 @@ export const INTERPOLATION_DELIMITER = `<60>`;
 export function isPropMetadataString(str: string): boolean {
   return str.indexOf(INTERPOLATION_DELIMITER) >= 0;
 }
+
+/**
+ * Unwrap a value which might be behind a closure (for forward declaration reasons).
+ */
+export function maybeUnwrapFn<T>(value: T | (() => T)): T {
+  if (value instanceof Function) {
+    return value();
+  } else {
+    return value;
+  }
+}

packages/core/test/render3/ivy/jit_spec.ts

@@ -158,6 +158,9 @@ ivyEnabled && describe('render3 jit', () => {
 
     const moduleDef: NgModuleDef<Module> = (Module as any).ngModuleDef;
     expect(moduleDef).toBeDefined();
+    if (!Array.isArray(moduleDef.declarations)) {
+      return fail('Expected an array');
+    }
     expect(moduleDef.declarations.length).toBe(1);
     expect(moduleDef.declarations[0]).toBe(Cmp);
   });

packages/core/testing/src/r3_test_bed.ts

@@ -732,7 +732,7 @@ export class TestBedRender3 implements Injector, TestBed {
    * @internal
    */
   _getComponentFactories(moduleType: NgModuleType): ComponentFactory<any>[] {
-    return moduleType.ngModuleDef.declarations.reduce((factories, declaration) => {
+    return maybeUnwrapFn(moduleType.ngModuleDef.declarations).reduce((factories, declaration) => {
       const componentDef = (declaration as any).ngComponentDef;
       componentDef && factories.push(new ComponentFactory(componentDef, this._moduleRef));
       return factories;
@@ -820,3 +820,14 @@ class R3TestCompiler implements Compiler {
 class R3TestErrorHandler extends ErrorHandler {
   handleError(error: any) { throw error; }
 }
+
+/**
+ * Unwrap a value which might be behind a closure (for forward declaration reasons).
+ */
+function maybeUnwrapFn<T>(value: T | (() => T)): T {
+  if (value instanceof Function) {
+    return value();
+  } else {
+    return value;
+  }
+}