fix(@angular-devkit/build-angular): only collect coverage from files under sourceRoot (#11974)

In some cases when having libraries within the workspace this is causing a `Maximum call stack size exceeded`, Also for libraries coverage should be collected with the respective `ng test`

Closes #11934

Author: alan-agius4

packages/angular_devkit/build_angular/src/angular-cli-files/models/build-options.ts

@@ -74,6 +74,7 @@ export interface WebpackTestOptions extends BuildOptions {
 export interface WebpackConfigOptions<T = BuildOptions> {
   root: string;
   projectRoot: string;
+  sourceRoot?: string;
   buildOptions: T;
   tsConfig: ts.ParsedCommandLine;
   tsConfigPath: string;

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

@@ -23,7 +23,7 @@ import { WebpackConfigOptions, WebpackTestOptions } from '../build-options';
 export function getTestConfig(
   wco: WebpackConfigOptions<WebpackTestOptions>,
 ): webpack.Configuration {
-  const { root, buildOptions } = wco;
+  const { root, buildOptions, sourceRoot: include } = wco;
 
   const extraRules: webpack.Rule[] = [];
   const extraPlugins: webpack.Plugin[] = [];
@@ -46,10 +46,12 @@ export function getTestConfig(
     }
 
     extraRules.push({
-      test: /\.(js|ts)$/, loader: 'istanbul-instrumenter-loader',
+      test: /\.(js|ts)$/,
+      loader: 'istanbul-instrumenter-loader',
       options: { esModules: true },
       enforce: 'post',
       exclude,
+      include,
     });
   }
 

packages/angular_devkit/build_angular/src/karma/index.ts

@@ -71,11 +71,13 @@ export class KarmaBuilder implements Builder<KarmaBuilderSchema> {
           karmaOptions.browsers = options.browsers.split(',');
         }
 
+        const sourceRoot = builderConfig.sourceRoot && resolve(root, builderConfig.sourceRoot);
+
         karmaOptions.buildWebpack = {
           root: getSystemPath(root),
           projectRoot: getSystemPath(projectRoot),
           options: options as NormalizedKarmaBuilderSchema,
-          webpackConfig: this._buildWebpackConfig(root, projectRoot, host,
+          webpackConfig: this._buildWebpackConfig(root, projectRoot, sourceRoot, host,
             options as NormalizedKarmaBuilderSchema),
           // Pass onto Karma to emit BuildEvents.
           successCb: () => obs.next({ success: true }),
@@ -108,6 +110,7 @@ export class KarmaBuilder implements Builder<KarmaBuilderSchema> {
   private _buildWebpackConfig(
     root: Path,
     projectRoot: Path,
+    sourceRoot: Path | undefined,
     host: virtualFs.Host<fs.Stats>,
     options: NormalizedKarmaBuilderSchema,
   ) {
@@ -130,6 +133,7 @@ export class KarmaBuilder implements Builder<KarmaBuilderSchema> {
     wco = {
       root: getSystemPath(root),
       projectRoot: getSystemPath(projectRoot),
+      sourceRoot: sourceRoot && getSystemPath(sourceRoot),
       // TODO: use only this.options, it contains all flags and configs items already.
       buildOptions: compatOptions,
       tsConfig,

packages/angular_devkit/build_angular/test/karma/code-coverage_spec_large.ts

@@ -56,4 +56,52 @@ describe('Karma Builder code coverage', () => {
       }),
     ).toPromise().then(done, done.fail);
   }, 120000);
+
+  it(`should collect coverage from paths in 'sourceRoot'`, (done) => {
+    const overrides: Partial<NormalizedKarmaBuilderSchema> = { codeCoverage: true };
+
+    const files: { [path: string]: string } = {
+      './dist/my-lib/index.d.ts': `
+        export declare const title = 'app';
+      `,
+      './dist/my-lib/index.js': `
+        export const title = 'app';
+      `,
+      './src/app/app.component.ts': `
+        import { Component } from '@angular/core';
+        import { title } from 'my-lib';
+
+        @Component({
+          selector: 'app-root',
+          templateUrl: './app.component.html',
+          styleUrls: ['./app.component.css']
+        })
+        export class AppComponent {
+          title = title;
+        }
+      `,
+    };
+
+    host.writeMultipleFiles(files);
+
+    host.replaceInFile('tsconfig.json', /"baseUrl": ".\/",/, `
+      "baseUrl": "./",
+      "paths": {
+        "my-lib": [
+          "./dist/my-lib"
+        ]
+      },
+    `);
+
+    runTargetSpec(host, karmaTargetSpec, overrides).pipe(
+      // It seems like the coverage files take a while being written to disk, so we wait 500ms here.
+      debounceTime(500),
+      tap(buildEvent => {
+        expect(buildEvent.success).toBe(true);
+        expect(host.scopedSync().exists(coverageFilePath)).toBe(true);
+        const content = virtualFs.fileBufferToString(host.scopedSync().read(coverageFilePath));
+        expect(content).not.toContain('my-lib');
+      }),
+    ).toPromise().then(done, done.fail);
+  }, 120000);
 });