feat(ivy): implement `Renderer.getSwitchableDeclarations` (#25534)

This supports the "ngcc ivy switch" specified in #25238.

PR Close #25534

packages/compiler-cli/src/ngcc/src/rendering/esm2015_renderer.ts

@@ -7,6 +7,7 @@
  */
 import * as ts from 'typescript';
 import MagicString from 'magic-string';
+import {POST_NGCC_MARKER, PRE_NGCC_MARKER} from '../host/ngcc_host';
 import {AnalyzedClass} from '../analyzer';
 import {Renderer} from './renderer';
 
@@ -70,4 +71,14 @@ export class Esm2015Renderer extends Renderer {
       }
     });
   }
+
+  rewriteSwitchableDeclarations(outputText: MagicString, sourceFile: ts.SourceFile): void {
+    const declarations = this.host.getSwitchableDeclarations(sourceFile);
+    declarations.forEach(declaration => {
+      const start = declaration.initializer.getStart();
+      const end = declaration.initializer.getEnd();
+      const replacement = declaration.initializer.text.replace(PRE_NGCC_MARKER, POST_NGCC_MARKER);
+      outputText.overwrite(start, end, replacement);
+    });
+  }
 }

packages/compiler-cli/src/ngcc/src/rendering/renderer.ts

@@ -89,9 +89,13 @@ export abstract class Renderer {
         file.sourceFile);
 
     this.addImports(outputText, importManager.getAllImports(file.sourceFile.fileName, null));
-    // QUESTION: do we need to remove contructor param metadata and property decorators?
+
+    // TODO: remove contructor param metadata and property decorators (we need info from the
+    // handlers to do this)
     this.removeDecorators(outputText, decoratorsToRemove);
 
+    this.rewriteSwitchableDeclarations(outputText, file.sourceFile);
+
     return this.renderSourceAndMap(file, input, outputText, targetPath);
   }
 
@@ -102,6 +106,8 @@ export abstract class Renderer {
       output: MagicString, analyzedClass: AnalyzedClass, definitions: string): void;
   protected abstract removeDecorators(
       output: MagicString, decoratorsToRemove: Map<ts.Node, ts.Node[]>): void;
+  protected abstract rewriteSwitchableDeclarations(
+      outputText: MagicString, sourceFile: ts.SourceFile): void;
 
   /**
    * Add the decorator nodes that are to be removed to a map

packages/compiler-cli/src/ngcc/test/rendering/esm2015_renderer_spec.ts

@@ -46,6 +46,19 @@ export class C {}
 C.decorators = [
   { type: Directive, args: [{ selector: '[c]' }] },
 ];
+let compileNgModuleFactory = compileNgModuleFactory__PRE_NGCC__;
+let badlyFormattedVariable = __PRE_NGCC__badlyFormattedVariable;
+
+function compileNgModuleFactory__PRE_NGCC__(injector, options, moduleType) {
+  const compilerFactory = injector.get(CompilerFactory);
+  const compiler = compilerFactory.createCompiler([options]);
+  return compiler.compileModuleAsync(moduleType);
+}
+
+function compileNgModuleFactory__POST_NGCC__(injector, options, moduleType) {
+  ngDevMode && assertNgModuleType(moduleType);
+  return Promise.resolve(new R3NgModuleFactory(moduleType));
+}
 // Some other content`
 };
 
@@ -82,6 +95,29 @@ export class A {}`);
     });
   });
 
+  describe('rewriteSwitchableDeclarations', () => {
+    it('should switch marked declaration initializers', () => {
+      const {renderer, program} = setup(PROGRAM);
+      const file = program.getSourceFile('some/file.js');
+      if (file === undefined) {
+        throw new Error(`Could not find source file`);
+      }
+      const output = new MagicString(PROGRAM.contents);
+      renderer.rewriteSwitchableDeclarations(output, file);
+      expect(output.toString())
+          .not.toContain(`let compileNgModuleFactory = compileNgModuleFactory__PRE_NGCC__;`);
+      expect(output.toString())
+          .toContain(`let badlyFormattedVariable = __PRE_NGCC__badlyFormattedVariable;`);
+      expect(output.toString())
+          .toContain(`let compileNgModuleFactory = compileNgModuleFactory__POST_NGCC__;`);
+      expect(output.toString())
+          .toContain(
+              `function compileNgModuleFactory__PRE_NGCC__(injector, options, moduleType) {`);
+      expect(output.toString())
+          .toContain(
+              `function compileNgModuleFactory__POST_NGCC__(injector, options, moduleType) {`);
+    });
+  });
 
   describe('addDefinitions', () => {
     it('should insert the definitions directly after the class declaration', () => {

packages/compiler-cli/src/ngcc/test/rendering/renderer_spec.ts

@@ -29,6 +29,9 @@ class TestRenderer extends Renderer {
   removeDecorators(output: MagicString, decoratorsToRemove: Map<ts.Node, ts.Node[]>) {
     output.prepend('\n// REMOVE DECORATORS\n');
   }
+  rewriteSwitchableDeclarations(output: MagicString, sourceFile: ts.SourceFile): void {
+    output.prepend('\n// REWRITTEN DECLARATIONS\n');
+  }
 }
 
 function createTestRenderer() {
@@ -68,7 +71,7 @@ describe('Renderer', () => {
     ]
   });
   const RENDERED_CONTENTS =
-      `\n// REMOVE DECORATORS\n\n// ADD IMPORTS\n\n// ADD CONSTANTS\n\n// ADD DEFINITIONS\n` +
+      `\n// REWRITTEN DECLARATIONS\n\n// REMOVE DECORATORS\n\n// ADD IMPORTS\n\n// ADD CONSTANTS\n\n// ADD DEFINITIONS\n` +
       INPUT_PROGRAM.contents;
   const OUTPUT_PROGRAM_MAP = fromObject({
     'version': 3,
@@ -78,14 +81,14 @@ describe('Renderer', () => {
       'import { Directive } from \'@angular/core\';\nexport class A {\n    foo(x) {\n        return x;\n    }\n}\nA.decorators = [\n    { type: Directive, args: [{ selector: \'[a]\' }] }\n];\n'
     ],
     'names': [],
-    'mappings': ';;;;;;;;AAAA;;;;;;;;;'
+    'mappings': ';;;;;;;;;;AAAA;;;;;;;;;'
   });
 
   const MERGED_OUTPUT_PROGRAM_MAP = fromObject({
     'version': 3,
     'sources': ['/file.ts'],
     'names': [],
-    'mappings': ';;;;;;;;AAAA',
+    'mappings': ';;;;;;;;;;AAAA',
     'file': '/output_file.js',
     'sourcesContent': [
       'import { Directive } from \'@angular/core\';\nexport class A {\n    foo(x: string): string {\n        return x;\n    }\n    static decorators = [\n        { type: Directive, args: [{ selector: \'[a]\' }] }\n    ];\n}'