fix(@angular/build): resolve "Controller is already closed" error in Karma

This issue stems from the `Some of your tests did a full page reload` error, which occurs because `karmaOptions.client.clearContext` is set to `true` when `singleRun` is `false`, even though Karma is running in watch mode. Previously, the `watch` flag was configured inconsistently across multiple locations, leading to misalignment.

Closes #30506

(cherry picked from commit 49676c8)

Author: alan-agius4

packages/angular/build/src/builders/karma/application_builder.ts

@@ -24,7 +24,7 @@ import { ApplicationBuilderInternalOptions } from '../application/options';
 import { Result, ResultFile, ResultKind } from '../application/results';
 import { OutputHashing } from '../application/schema';
 import { findTests, getTestEntrypoints } from './find-tests';
-import { Schema as KarmaBuilderOptions } from './schema';
+import { NormalizedKarmaBuilderOptions } from './options';
 
 const localResolve = createRequire(__filename).resolve;
 const isWindows = process.platform === 'win32';
@@ -275,7 +275,7 @@ function injectKarmaReporter(
 }
 
 export function execute(
-  options: KarmaBuilderOptions,
+  options: NormalizedKarmaBuilderOptions,
   context: BuilderContext,
   karmaOptions: ConfigOptions,
   transforms: {
@@ -359,14 +359,14 @@ function normalizePolyfills(polyfills: string | string[] | undefined): [string[]
 }
 
 async function collectEntrypoints(
-  options: KarmaBuilderOptions,
+  options: NormalizedKarmaBuilderOptions,
   context: BuilderContext,
   projectSourceRoot: string,
 ): Promise<Map<string, string>> {
   // Glob for files to test.
   const testFiles = await findTests(
-    options.include ?? [],
-    options.exclude ?? [],
+    options.include,
+    options.exclude,
     context.workspaceRoot,
     projectSourceRoot,
   );
@@ -376,7 +376,7 @@ async function collectEntrypoints(
 
 // eslint-disable-next-line max-lines-per-function
 async function initializeApplication(
-  options: KarmaBuilderOptions,
+  options: NormalizedKarmaBuilderOptions,
   context: BuilderContext,
   karmaOptions: ConfigOptions,
   transforms: {
@@ -435,7 +435,7 @@ async function initializeApplication(
     scripts: options.scripts,
     polyfills,
     webWorkerTsConfig: options.webWorkerTsConfig,
-    watch: options.watch ?? !karmaOptions.singleRun,
+    watch: options.watch,
     stylePreprocessorOptions: options.stylePreprocessorOptions,
     inlineStyleLanguage: options.inlineStyleLanguage,
     fileReplacements: options.fileReplacements,

packages/angular/build/src/builders/karma/index.ts

@@ -15,6 +15,7 @@ import {
 import type { ConfigOptions } from 'karma';
 import { createRequire } from 'node:module';
 import path from 'node:path';
+import { NormalizedKarmaBuilderOptions, normalizeOptions } from './options';
 import type { Schema as KarmaBuilderOptions } from './schema';
 
 export type KarmaConfigOptions = ConfigOptions & {
@@ -34,19 +35,17 @@ export async function* execute(
   } = {},
 ): AsyncIterable<BuilderOutput> {
   const { execute } = await import('./application_builder');
-  const karmaOptions = getBaseKarmaOptions(options, context);
+  const normalizedOptions = normalizeOptions(options);
+  const karmaOptions = getBaseKarmaOptions(normalizedOptions, context);
 
-  yield* execute(options, context, karmaOptions, transforms);
+  yield* execute(normalizedOptions, context, karmaOptions, transforms);
 }
 
 function getBaseKarmaOptions(
-  options: KarmaBuilderOptions,
+  options: NormalizedKarmaBuilderOptions,
   context: BuilderContext,
 ): KarmaConfigOptions {
-  let singleRun: boolean | undefined;
-  if (options.watch !== undefined) {
-    singleRun = !options.watch;
-  }
+  const singleRun = !options.watch;
 
   // Determine project name from builder context target
   const projectName = context.target?.project;
@@ -67,21 +66,12 @@ function getBaseKarmaOptions(
   karmaOptions.client.clearContext ??= singleRun ?? false; // `singleRun` defaults to `false` per Karma docs.
 
   // Convert browsers from a string to an array
-  if (typeof options.browsers === 'string' && options.browsers) {
-    karmaOptions.browsers = options.browsers.split(',').map((browser) => browser.trim());
-  } else if (options.browsers === false) {
-    karmaOptions.browsers = [];
+  if (options.browsers) {
+    karmaOptions.browsers = options.browsers;
   }
 
   if (options.reporters) {
-    // Split along commas to make it more natural, and remove empty strings.
-    const reporters = options.reporters
-      .reduce<string[]>((acc, curr) => acc.concat(curr.split(',')), [])
-      .filter((x) => !!x);
-
-    if (reporters.length > 0) {
-      karmaOptions.reporters = reporters;
-    }
+    karmaOptions.reporters = options.reporters;
   }
 
   return karmaOptions;

packages/angular/build/src/builders/karma/options.ts

@@ -0,0 +1,36 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import { Schema as KarmaBuilderOptions } from './schema';
+
+export type NormalizedKarmaBuilderOptions = Awaited<ReturnType<typeof normalizeOptions>>;
+
+export function normalizeOptions(options: KarmaBuilderOptions) {
+  const { watch = true, include = [], exclude = [], reporters = [], browsers, ...rest } = options;
+
+  let normalizedBrowsers: string[] | undefined;
+  if (typeof options.browsers === 'string' && options.browsers) {
+    normalizedBrowsers = options.browsers.split(',').map((browser) => browser.trim());
+  } else if (options.browsers === false) {
+    normalizedBrowsers = [];
+  }
+
+  // Split along commas to make it more natural, and remove empty strings.
+  const normalizedReporters = reporters
+    .reduce<string[]>((acc, curr) => acc.concat(curr.split(',')), [])
+    .filter((x) => !!x);
+
+  return {
+    reporters: normalizedReporters.length ? normalizedReporters : undefined,
+    browsers: normalizedBrowsers,
+    watch,
+    include,
+    exclude,
+    ...rest,
+  };
+}

packages/angular/build/src/builders/karma/schema.json

@@ -229,7 +229,8 @@
     },
     "watch": {
       "type": "boolean",
-      "description": "Run build when files change."
+      "description": "Run build when files change.",
+      "default": true
     },
     "poll": {
       "type": "number",