fix(compiler): also create `.ngfactory.js` files in non obvious cases (#19301)

E.g. when an exported class contains a ctor argument which is
from another compilation unit.

PR Close #19301

packages/compiler-cli/test/ngc_spec.ts

@@ -840,6 +840,7 @@ describe('ngc transformer command-line', () => {
           })
           export class Module {}
         `);
+      write('lib1/class1.ts', `export class Class1 {}`);
 
       // Lib 2
       write('lib2/tsconfig-lib2.json', `{
@@ -855,6 +856,13 @@ describe('ngc transformer command-line', () => {
       write('lib2/module.ts', `
           export {Module} from 'lib1_built/module';
         `);
+      write('lib2/class2.ts', `
+        import {Class1} from 'lib1_built/class1';
+
+        export class Class2 {
+          constructor(class1: Class1) {}
+        }
+      `);
 
       // Application
       write('app/tsconfig-app.json', `{
@@ -904,6 +912,12 @@ describe('ngc transformer command-line', () => {
       shouldExist('lib2_built/module.ngfactory.js');
       shouldExist('lib2_built/module.ngfactory.d.ts');
 
+      shouldExist('lib2_built/class2.ngsummary.json');
+      shouldNotExist('lib2_built/class2.ngsummary.js');
+      shouldNotExist('lib2_built/class2.ngsummary.d.ts');
+      shouldExist('lib2_built/class2.ngfactory.js');
+      shouldExist('lib2_built/class2.ngfactory.d.ts');
+
       // app
       // make `shouldExist` / `shouldNotExist` relative to `built`
       outDir = path.resolve(basePath, 'built');

packages/compiler/src/aot/compiler.ts

@@ -34,7 +34,7 @@ import {ResolvedStaticSymbol, StaticSymbolResolver} from './static_symbol_resolv
 import {createForJitStub, serializeSummaries} from './summary_serializer';
 import {ngfactoryFilePath, splitTypescriptSuffix, summaryFileName, summaryForJitFileName, summaryForJitName} from './util';
 
-export enum StubEmitFlags {
+enum StubEmitFlags {
   Basic = 1 << 0,
   TypeCheck = 1 << 1,
   All = TypeCheck | Basic
@@ -170,22 +170,14 @@ export class AotCompiler {
       }
     });
 
-    // make sure we create a .ngfactory if we have a least one component
-    // in the file.
+    // Make sure we create a .ngfactory if we have a injectable/directive/pipe/NgModule
+    // or a reference to a non source file.
+    // Note: This is overestimating the required .ngfactory files as the real calculation is harder.
     // Only do this for StubEmitFlags.Basic, as adding a type check block
     // does not change this file (as we generate type check blocks based on NgModules).
     if (outputCtx.statements.length === 0 && (emitFlags & StubEmitFlags.Basic) &&
-        file.directives.some(
-            dir => this._metadataResolver.getNonNormalizedDirectiveMetadata(
-                                             dir) !.metadata.isComponent)) {
-      _createEmptyStub(outputCtx);
-    }
-
-    // make sure we create a .ngfactory if we reexport a non source file.
-    // Only do this for StubEmitFlags.Basic, as adding a type check block
-    // does not change this file (as we generate type check blocks based on NgModules).
-    if (outputCtx.statements.length === 0 && (emitFlags & StubEmitFlags.Basic) &&
-        file.exportsNonSourceFiles) {
+        (file.directives.length || file.pipes.length || file.injectables.length ||
+         file.ngModules.length || file.exportsNonSourceFiles)) {
       _createEmptyStub(outputCtx);
     }
 
@@ -648,22 +640,29 @@ export function analyzeFile(
       if (!symbolMeta || symbolMeta.__symbolic === 'error') {
         return;
       }
-      exportsNonSourceFiles =
-          exportsNonSourceFiles || isValueExportingNonSourceFile(host, symbolMeta);
+      let isNgSymbol = false;
       if (symbolMeta.__symbolic === 'class') {
         if (metadataResolver.isDirective(symbol)) {
+          isNgSymbol = true;
           directives.push(symbol);
         } else if (metadataResolver.isPipe(symbol)) {
+          isNgSymbol = true;
           pipes.push(symbol);
         } else if (metadataResolver.isInjectable(symbol)) {
+          isNgSymbol = true;
           injectables.push(symbol);
         } else {
           const ngModule = metadataResolver.getNgModuleMetadata(symbol, false);
           if (ngModule) {
+            isNgSymbol = true;
             ngModules.push(ngModule);
           }
         }
       }
+      if (!isNgSymbol) {
+        exportsNonSourceFiles =
+            exportsNonSourceFiles || isValueExportingNonSourceFile(host, symbolMeta);
+      }
     });
   }
   return {