fix(@angular-devkit/build-angular): don't use parent modules while deduping

packages/angular_devkit/build_angular/src/angular-cli-files/models/webpack-configs/common.ts

@@ -488,7 +488,6 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
       modules: [wco.tsConfig.options.baseUrl || projectRoot, 'node_modules'],
       plugins: [
         PnpWebpackPlugin,
-        new DedupeModuleResolvePlugin({ verbose: buildOptions.verbose }),
       ],
     },
     resolveLoader: {
@@ -606,6 +605,7 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
       // https://github.com/angular/angular/issues/11580
       // With VE the correct context is added in @ngtools/webpack, but Ivy doesn't need it at all.
       new ContextReplacementPlugin(/\@angular(\\|\/)core(\\|\/)/),
+      new DedupeModuleResolvePlugin({ verbose: buildOptions.verbose }),
       ...extraPlugins,
     ],
   };

packages/angular_devkit/build_angular/src/angular-cli-files/plugins/dedupe-module-resolve-plugin.ts

@@ -6,89 +6,87 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-interface NormalModuleFactoryRequest {
+import { Compiler } from 'webpack';
+
+interface AfterResolveResult {
   request: string;
+  resource: string;
   context: {
     issuer: string;
   };
-  relativePath: string;
-  path: string;
-  descriptionFileData: {
-    name?: string;
-    version?: string;
+  resourceResolveData: {
+    relativePath: string;
+    descriptionFileRoot: string;
+    descriptionFilePath: string;
+    descriptionFileData: {
+      name?: string;
+      version?: string;
+    };
   };
-  descriptionFileRoot: string;
-  descriptionFilePath: string;
-  directory?: boolean;
-  file?: boolean;
 }
 
 export interface DedupeModuleResolvePluginOptions {
   verbose?: boolean;
 }
 
 /**
- * DedupeModuleResolvePlugin is a webpack resolver plugin which dedupes modules with the same name and versions
+ * DedupeModuleResolvePlugin is a webpack plugin which dedupes modules with the same name and versions
  * that are laid out in different parts of the node_modules tree.
  *
  * This is needed because Webpack relies on package managers to hoist modules and doesn't have any deduping logic.
+ *
+ * This is similar to how Webpack's 'NormalModuleReplacementPlugin' works
+ * @see https://github.com/webpack/webpack/blob/4a1f068828c2ab47537d8be30d542cd3a1076db4/lib/NormalModuleReplacementPlugin.js#L9
  */
 export class DedupeModuleResolvePlugin {
-  modules = new Map<string, NormalModuleFactoryRequest>();
+  modules = new Map<string, { request: string, resource: string }>();
 
   constructor(private options?: DedupeModuleResolvePluginOptions) { }
 
   // tslint:disable-next-line: no-any
-  apply(resolver: any) {
-    resolver
-      .getHook('before-described-relative')
-      .tapPromise('DedupeModuleResolvePlugin', async (request: NormalModuleFactoryRequest) => {
-        if (request.relativePath !== '.') {
+  apply(compiler: Compiler) {
+    compiler.hooks.normalModuleFactory.tap('DedupeModuleResolvePlugin', nmf => {
+      nmf.hooks.afterResolve.tap('DedupeModuleResolvePlugin', (result: AfterResolveResult | undefined) => {
+        if (!result) {
           return;
         }
 
-        // When either of these properties is undefined. It typically means it's a link.
-        // In which case we shouldn't try to dedupe it.
-        if (request.file === undefined || request.directory === undefined) {
-          return;
-        }
+        const { resource, request, resourceResolveData } = result;
+        const { descriptionFileData, relativePath } = resourceResolveData;
 
-        // Empty name or versions are no valid primary entrypoints of a library
-        if (!request.descriptionFileData.name || !request.descriptionFileData.version) {
+        // Empty name or versions are no valid primary  entrypoints of a library
+        if (!descriptionFileData.name || !descriptionFileData.version) {
           return;
         }
 
-        const moduleId = request.descriptionFileData.name + '@' + request.descriptionFileData.version;
+        const moduleId = descriptionFileData.name + '@' + descriptionFileData.version + ':' + relativePath;
         const prevResolvedModule = this.modules.get(moduleId);
 
         if (!prevResolvedModule) {
           // This is the first time we visit this module.
-          this.modules.set(moduleId, request);
+          this.modules.set(moduleId, {
+            resource,
+            request,
+          });
 
           return;
         }
 
-        const {
-          path,
-          descriptionFilePath,
-          descriptionFileRoot,
-        } = prevResolvedModule;
-
-        if (request.path === path) {
+        const { resource: prevResource, request: prevRequest } = prevResolvedModule;
+        if (result.resource === prevResource) {
           // No deduping needed.
           // Current path and previously resolved path are the same.
           return;
         }
 
         if (this.options?.verbose) {
           // tslint:disable-next-line: no-console
-          console.warn(`[DedupeModuleResolvePlugin]: ${request.path} -> ${path}`);
+          console.warn(`[DedupeModuleResolvePlugin]: ${result.resource} -> ${prevResource}`);
         }
 
         // Alter current request with previously resolved module.
-        request.path = path;
-        request.descriptionFileRoot = descriptionFileRoot;
-        request.descriptionFilePath = descriptionFilePath;
+        result.request = prevRequest;
       });
+    });
   }
 }

tests/legacy-cli/e2e/tests/misc/dedupe-duplicate-modules.ts

@@ -32,10 +32,10 @@ export default async function () {
   const { stderr } = await ng('build', '--verbose', '--no-vendor-chunk', '--no-progress');
   const outFile = 'dist/test-project/main.js';
 
-  if (/\[DedupeModuleResolvePlugin\]:.+tslib-1-copy -> .+tslib-1/.test(stderr)) {
+  if (/\[DedupeModuleResolvePlugin\]:.+tslib-1-copy\/.+ -> .+tslib-1\/.+/.test(stderr)) {
     await expectFileToMatch(outFile, './node_modules/tslib-1/tslib.es6.js');
     await expectToFail(() => expectFileToMatch(outFile, './node_modules/tslib-1-copy/tslib.es6.js'));
-  } else if (/\[DedupeModuleResolvePlugin\]:.+tslib-1 -> .+tslib-1-copy/.test(stderr)) {
+  } else if (/\[DedupeModuleResolvePlugin\]:.+tslib-1\/.+ -> .+tslib-1-copy\/.+/.test(stderr)) {
     await expectFileToMatch(outFile, './node_modules/tslib-1-copy/tslib.es6.js');
     await expectToFail(() => expectFileToMatch(outFile, './node_modules/tslib-1/tslib.es6.js'));
   } else {