refactor(@angular/build): remove source-map-support from Vitest runner

This change removes the injection of `source-map-support` in Vitest browser tests and enables sourcemap rebasing for coverage runs as well. This allows Vitest's native remapper to handle stack traces and coverage correctly without needing the external polyfill in the browser. The E2E tests have been verified to pass with these changes. The unused `createSourcemapSupportPlugin` function has also been removed.

Author: clydin

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

@@ -232,16 +232,12 @@ export async function createVitestConfigPlugin(
         delete config.plugins;
       }
 
-      // Add browser source map support if coverage is enabled
+      // Validate browser coverage support if coverage is enabled
       if (
         (browser || testConfig?.browser?.enabled) &&
         (options.coverage.enabled || testConfig?.coverage?.enabled)
       ) {
-        // Validate that enabled browsers support the selected coverage provider
         validateBrowserCoverage(browser, testConfig?.browser, determinedProvider);
-
-        projectPlugins.unshift(createSourcemapSupportPlugin());
-        setupFiles.unshift('virtual:source-map-support');
       }
 
       const projectResolver = createRequire(projectSourceRoot + '/').resolve;
@@ -408,7 +404,7 @@ export function createVitestPlugins(pluginOptions: PluginOptions): VitestPlugins
 
           const map = sourceMapText ? JSON.parse(sourceMapText) : undefined;
           if (map) {
-            adjustSourcemapSources(map, !vitestConfig?.coverage?.enabled, workspaceRoot, id);
+            adjustSourcemapSources(map, true, workspaceRoot, id);
           }
 
           return {
@@ -475,36 +471,6 @@ function adjustSourcemapSources(
   }
 }
 
-function createSourcemapSupportPlugin(): VitestPlugins[0] {
-  return {
-    name: 'angular:source-map-support',
-    enforce: 'pre',
-    resolveId(source) {
-      if (source.includes('virtual:source-map-support')) {
-        return '\0source-map-support';
-      }
-    },
-    async load(id) {
-      if (id !== '\0source-map-support') {
-        return;
-      }
-
-      const packageResolve = createRequire(__filename).resolve;
-      const supportPath = packageResolve('source-map-support/browser-source-map-support.js');
-
-      const content = await readFile(supportPath, 'utf-8');
-
-      // The `source-map-support` library currently relies on `this` being defined in the global scope.
-      // However, when running in an ESM environment, `this` is undefined.
-      // To workaround this, we patch the library to use `globalThis` instead of `this`.
-      return (
-        content.replaceAll(/this\.(define|sourceMapSupport|base64js)/g, 'globalThis.$1') +
-        '\n;globalThis.sourceMapSupport.install();'
-      );
-    },
-  };
-}
-
 interface CustomBrowserConfigOptions {
   enabled?: boolean;
   instances?: { browser: string }[];