refactor(@angular-devkit/build-angular): remove unneeded @angular/core System.import workarounds

With the removal of support for the string form of `loadChildren` within the Angular router, the usage of `System.import` has also been removal from `@angular/core`. This removal allows for the additional removal of all workarounds within the Angular CLI due to the `System.import` usage. Webpack's deprecated support for `System.import` was previously required to be enabled which resulted in warnings that then needed to be suppressed. A Webpack context dependency replacement was also previously required to prevent Webpack from failing due to the otherwise unknown behavior of the `System.import` call. All of these workarounds have now been removed.

Author: clydin

packages/angular_devkit/build_angular/src/builders/browser/tests/options/named-chunks_spec.ts

@@ -11,7 +11,7 @@ import { BASE_OPTIONS, BROWSER_BUILDER_INFO, describeBuilder } from '../setup';
 
 const MAIN_OUTPUT = 'dist/main.js';
 const NAMED_LAZY_OUTPUT = 'dist/src_lazy-module_ts.js';
-const UNNAMED_LAZY_OUTPUT = 'dist/339.js';
+const UNNAMED_LAZY_OUTPUT = 'dist/629.js';
 
 describeBuilder(buildWebpackBrowser, BROWSER_BUILDER_INFO, (harness) => {
   describe('Option: "namedChunks"', () => {

packages/angular_devkit/build_angular/src/webpack/configs/common.ts

@@ -355,9 +355,6 @@ export async function getCommonConfig(wco: WebpackConfigOptions): Promise<Config
       hints: false,
     },
     ignoreWarnings: [
-      // Webpack 5+ has no facility to disable this warning.
-      // System.import is used in @angular/core for deprecated string-form lazy routes
-      /System.import\(\) is deprecated and will be removed soon/i,
       // https://github.com/webpack-contrib/source-map-loader/blob/b2de4249c7431dd8432da607e08f0f65e9d64219/src/index.js#L83
       /Failed to parse source map from/,
       // https://github.com/webpack-contrib/postcss-loader/blob/bd261875fdf9c596af4ffb3a1a73fe3c549befda/src/index.js#L153-L158
@@ -367,12 +364,6 @@ export async function getCommonConfig(wco: WebpackConfigOptions): Promise<Config
       // Show an error for missing exports instead of a warning.
       strictExportPresence: true,
       rules: [
-        {
-          // Mark files inside `@angular/core` as using SystemJS style dynamic imports.
-          // Removing this will cause deprecation warnings to appear.
-          test: /[/\\]@angular[/\\]core[/\\].+\.js$/,
-          parser: { system: true },
-        },
         {
           // Mark files inside `rxjs/add` as containing side effects.
           // If this is fixed upstream and the fixed version becomes the minimum
@@ -414,17 +405,7 @@ export async function getCommonConfig(wco: WebpackConfigOptions): Promise<Config
       chunkIds: buildOptions.namedChunks ? 'named' : 'deterministic',
       emitOnErrors: false,
     },
-    plugins: [
-      // Always replace the context for the System.import in angular/core to prevent warnings.
-      // https://github.com/angular/angular/issues/11580
-      new ContextReplacementPlugin(
-        /@angular[\\/]core[\\/]/,
-        path.join(projectRoot, '$_lazy_route_resources'),
-        {},
-      ),
-      new DedupeModuleResolvePlugin({ verbose: buildOptions.verbose }),
-      ...extraPlugins,
-    ],
+    plugins: [new DedupeModuleResolvePlugin({ verbose: buildOptions.verbose }), ...extraPlugins],
   };
 }
 

tests/legacy-cli/e2e/tests/build/worker.ts

@@ -33,7 +33,7 @@ export default async function () {
   await expectFileToMatch('dist/test-project/main.js', 'src_app_app_worker_ts');
 
   await ng('build', '--output-hashing=none');
-  const chunkId = '151';
+  const chunkId = '310';
   await expectFileToExist(`dist/test-project/${chunkId}.js`);
   await expectFileToMatch('dist/test-project/main.js', chunkId);