fix(@angular-devkit/build-angular): normalize asset source locations in Vite-based development server

The Vite-based development server uses an allow list to permit access to configured assets. This list
is checked internally to Vite by using its normalized path form. To ensure that assets provided by the
build are checked correctly on all platforms, the asset list is now normalized with Vite's path
normalization prior to being used.

Author: clydin

packages/angular_devkit/build_angular/src/builders/dev-server/vite-server.ts

@@ -191,7 +191,7 @@ export async function* serveWithVite(
     assetFiles.clear();
     if (result.assetFiles) {
       for (const asset of result.assetFiles) {
-        assetFiles.set('/' + normalizePath(asset.destination), asset.source);
+        assetFiles.set('/' + normalizePath(asset.destination), normalizePath(asset.source));
       }
     }
 

tests/legacy-cli/e2e/tests/commands/serve/assets.ts

@@ -0,0 +1,38 @@
+import { mkdir, rm, writeFile } from 'node:fs/promises';
+import assert from 'assert';
+import { ngServe, updateJsonFile } from '../../../utils/project';
+import { randomUUID } from 'node:crypto';
+
+export default async function () {
+  const outsideDirectoryName = `../outside-${randomUUID()}`;
+
+  await updateJsonFile('angular.json', (json) => {
+    json.projects['test-project'].architect.build.options.assets = [
+      'src/favicon.ico',
+      'src/assets',
+      // Ensure assets located outside the workspace root work with the dev server
+      { 'input': outsideDirectoryName, 'glob': '**/*', 'output': './outside' },
+    ];
+  });
+
+  await mkdir(outsideDirectoryName);
+  try {
+    await writeFile(`${outsideDirectoryName}/some-asset.xyz`, 'XYZ');
+
+    const port = await ngServe();
+
+    let response = await fetch(`http://localhost:${port}/favicon.ico`);
+    assert.strictEqual(response.status, 200);
+
+    response = await fetch(`http://localhost:${port}/outside/some-asset.xyz`);
+    assert.strictEqual(response.status, 200);
+    assert.strictEqual(await response.text(), 'XYZ');
+
+    // A non-existent file is assumed to be a potential route and will fallback to index.html
+    response = await fetch(`http://localhost:${port}/does-not-exist.png`);
+    assert.strictEqual(response.status, 200);
+    assert.match(await response.text(), /<html/);
+  } finally {
+    await rm(outsideDirectoryName, { force: true, recursive: true });
+  }
+}