fix(@angular-devkit/build-angular): disable glob mounting for patterns that start with a forward slash

By default, a glob pattern starting with a forward slash will be "mounted" onto the system root. This causes globs to escape the workspace root.

With this change we configure disable glob "mounting".

Closes angular#23467

Author: alan-agius4

packages/angular_devkit/build_angular/src/builders/karma/tests/options/code-coverage-exclude_spec.ts

@@ -37,6 +37,21 @@ describeBuilder(execute, KARMA_BUILDER_INFO, (harness) => {
       harness.expectFile(coveragePath).content.not.toContain('app.component.ts');
     });
 
+    it('should exclude file from coverage when set when glob starts with a forward slash', async () => {
+      harness.useTarget('test', {
+        ...BASE_OPTIONS,
+        codeCoverage: true,
+        codeCoverageExclude: ['/**/app.component.ts'],
+      });
+
+      const { result } = await harness.executeOnce();
+
+      expect(result?.success).toBeTrue();
+
+      await setTimeoutPromise(1000);
+      harness.expectFile(coveragePath).content.not.toContain('app.component.ts');
+    });
+
     it('should not exclude file from coverage when set', async () => {
       harness.useTarget('test', {
         ...BASE_OPTIONS,

packages/angular_devkit/build_angular/src/utils/copy-assets.ts

@@ -37,6 +37,7 @@ export async function copyAssets(
       cwd,
       dot: true,
       nodir: true,
+      nomount: true,
       ignore: entry.ignore ? defaultIgnore.concat(entry.ignore) : defaultIgnore,
       follow: entry.followSymlinks,
     });

packages/angular_devkit/build_angular/src/webpack/utils/helpers.ts

@@ -128,7 +128,7 @@ export function getInstrumentationExcludedPaths(
 
   for (const excludeGlob of excludedPaths) {
     glob
-      .sync(excludeGlob, { nodir: true, cwd: sourceRoot })
+      .sync(excludeGlob, { nodir: true, cwd: sourceRoot, nomount: true })
       .forEach((p) => excluded.add(path.join(sourceRoot, p)));
   }