fix(@angular/build): correct Vitest coverage include handling for virtual files

Addresses an issue where user-defined `coverageInclude` patterns in Vitest
could incorrectly exclude bundled virtual files during the pre-sourcemap
coverage check, leading to incomplete or empty coverage reports.

This change modifies the `generateCoverageOption` function to augment
user-provided `coverageInclude` arrays with specific globs (`spec-*.js`,
`chunk-*.js`) that match the internal bundled test entry points and code
chunks. This ensures that all necessary files are considered during Vitest's
initial coverage pass, while still respecting the user's original `include`
patterns for the post-sourcemap remapping.

Author: clydin

packages/angular/build/src/builders/unit-test/runners/vitest/plugins.ts

@@ -285,7 +285,10 @@ async function generateCoverageOption(
   return {
     enabled: coverage.enabled,
     excludeAfterRemap: true,
-    include: coverage.include,
+    // Vitest performs a pre-check and a post-check for sourcemaps.
+    // The pre-check uses the bundled files, so specific bundled entry points and chunks need to be included.
+    // The post-check uses the original source files, so the user's include is used.
+    ...(coverage.include ? { include: ['spec-*.js', 'chunk-*.js', ...coverage.include] } : {}),
     reportsDirectory: toPosixPath(path.join('coverage', projectName)),
     thresholds: coverage.thresholds,
     watermarks: coverage.watermarks,

packages/angular/build/src/builders/unit-test/tests/options/code-coverage-include_spec.ts

@@ -0,0 +1,82 @@
+/**
+ * @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 { execute } from '../../index';
+import {
+  BASE_OPTIONS,
+  describeBuilder,
+  UNIT_TEST_BUILDER_INFO,
+  setupApplicationTarget,
+} from '../setup';
+
+describeBuilder(execute, UNIT_TEST_BUILDER_INFO, (harness) => {
+  describe('Option: "coverageInclude"', () => {
+    beforeEach(async () => {
+      setupApplicationTarget(harness);
+      await harness.writeFiles({
+        'src/app/included.ts': `export const a = 1;`,
+        'src/app/included.spec.ts': `
+          import { a } from './included';
+          describe('included', () => {
+            it('should work', () => {
+              expect(a).toBe(1);
+            });
+          });
+        `,
+        'src/app/excluded.ts': `export const b = 2;`,
+      });
+    });
+
+    it('should only include and report coverage for files that match the glob pattern', async () => {
+      harness.useTarget('test', {
+        ...BASE_OPTIONS,
+        coverage: true,
+        coverageInclude: ['**/included.ts'],
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+
+      const summary = JSON.parse(harness.readFile('coverage/test/coverage-final.json'));
+      const summaryKeys = Object.keys(summary);
+
+      const includedKey = summaryKeys.find((key) => key.endsWith('src/app/included.ts'));
+      const excludedKey = summaryKeys.find((key) => key.endsWith('src/app/excluded.ts'));
+
+      // Check that the included file is in the report and the excluded one is not.
+      expect(includedKey).toBeDefined();
+      expect(excludedKey).toBeUndefined();
+
+      // Check that the coverage data for the included file is valid.
+      const includedCoverage = summary[includedKey!];
+      // The file has one statement, and it should have been executed once.
+      expect(includedCoverage.s['0']).toBe(1);
+    });
+
+    it('should only include referenced files when no include pattern is provided', async () => {
+      harness.useTarget('test', {
+        ...BASE_OPTIONS,
+        coverage: true,
+        // coverageInclude is not provided, so only referenced files should be included.
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+      const summary = JSON.parse(harness.readFile('coverage/test/coverage-final.json'));
+      const summaryKeys = Object.keys(summary);
+
+      const includedKey = summaryKeys.find((key) => key.endsWith('src/app/included.ts'));
+      const excludedKey = summaryKeys.find((key) => key.endsWith('src/app/excluded.ts'));
+
+      // The included file is referenced by its spec and should be in the report.
+      expect(includedKey).toBeDefined();
+      // The excluded file is not referenced and should NOT be in the report.
+      expect(excludedKey).toBeUndefined();
+    });
+  });
+});