fix(@angular/build): resolve assets correctly during i18n prerendering

In i18n static output builds, requests for assets made during prerendering (e.g., via `HttpClient`) include the locale's `baseHref`. However, the in-memory asset mapping used by the patched server-side `fetch` did not account for this `baseHref`, causing assets to fail to resolve.

Closes angular#32713

(cherry picked from commit f30f890)

Author: alan-agius4

packages/angular/build/src/utils/server-rendering/prerender.ts

@@ -96,7 +96,9 @@ export async function prerenderPages(
 
   const assetsReversed: Record</** Destination */ string, /** Source */ string> = {};
   for (const { source, destination } of assets) {
-    assetsReversed[addLeadingSlash(toPosixPath(destination))] = source;
+    // Assets are not stored with baseHref when using i18n,
+    // we append the base href so that requests are resolved correctly.
+    assetsReversed[joinUrlParts(baseHref, toPosixPath(destination))] = source;
   }
 
   // Get routes to prerender

tests/e2e/tests/build/server-rendering/server-routes-output-mode-static-i18n-http-calls.ts

@@ -0,0 +1,137 @@
+import assert, { match } from 'node:assert';
+import { join } from 'node:path';
+import { readFile, writeMultipleFiles } from '../../../utils/fs';
+import { ng, noSilentNg, silentNg } from '../../../utils/process';
+import { getGlobalVariable } from '../../../utils/env';
+import { installWorkspacePackages, uninstallPackage } from '../../../utils/packages';
+import { useSha } from '../../../utils/project';
+import { langTranslations, setupI18nConfig } from '../../i18n/setup';
+
+export default async function () {
+  assert(
+    getGlobalVariable('argv')['esbuild'],
+    'This test should not be called in the Webpack suite.',
+  );
+
+  // Setup project
+  await setupI18nConfig();
+
+  // Forcibly remove in case another test doesn't clean itself up.
+  await uninstallPackage('@angular/ssr');
+  await ng('add', '@angular/ssr', '--skip-confirmation', '--skip-install');
+  await useSha();
+  await installWorkspacePackages();
+
+  await writeMultipleFiles({
+    // Add asset
+    'public/media.json': JSON.stringify({ dataFromAssets: true }),
+    // Update component to do an HTTP call to asset and API.
+    'src/app/app.ts': `
+    import { ChangeDetectorRef, Component, inject } from '@angular/core';
+    import { JsonPipe } from '@angular/common';
+    import { RouterOutlet } from '@angular/router';
+    import { HttpClient } from '@angular/common/http';
+
+    @Component({
+      selector: 'app-root',
+      imports: [JsonPipe, RouterOutlet],
+      template: \`
+        <p>{{ assetsData | json }}</p>
+        <p>{{ apiData | json }}</p>
+        <router-outlet></router-outlet>
+      \`,
+    })
+    export class App {
+      assetsData: any;
+      apiData: any;
+      private readonly cdr: ChangeDetectorRef = inject(ChangeDetectorRef);
+
+      constructor() {
+        const http = inject(HttpClient);
+
+        http.get('media.json').toPromise().then((d) => {
+          this.assetsData = d;
+          this.cdr.markForCheck();
+        });
+
+        http.get('/api').toPromise().then((d) => {
+          this.apiData = d;
+          this.cdr.markForCheck();
+        });
+      }
+    }
+    `,
+    // Add http client and route
+    'src/app/app.config.ts': `
+      import { ApplicationConfig } from '@angular/core';
+      import { provideRouter } from '@angular/router';
+
+      import { Home } from './home/home';
+      import { provideClientHydration } from '@angular/platform-browser';
+      import { provideHttpClient, withFetch } from '@angular/common/http';
+
+      export const appConfig: ApplicationConfig = {
+        providers: [
+          provideRouter([{
+            path: 'home',
+            component: Home,
+          }]),
+          provideClientHydration(),
+          provideHttpClient(withFetch()),
+        ],
+      };
+    `,
+    'src/server.ts': `
+      import { AngularNodeAppEngine, writeResponseToNodeResponse, isMainModule, createNodeRequestHandler } from '@angular/ssr/node';
+      import express from 'express';
+      import { join } from 'node:path';
+
+      export function app(): express.Express {
+        const server = express();
+        const browserDistFolder = join(import.meta.dirname, '../browser');
+        const angularNodeAppEngine = new AngularNodeAppEngine();
+
+        server.get('/api', (req, res) => {
+          res.json({ dataFromAPI: true })
+        });
+
+        server.use(express.static(browserDistFolder, {
+          maxAge: '1y',
+          index: 'index.html'
+        }));
+
+        server.use((req, res, next) => {
+          angularNodeAppEngine.handle(req)
+            .then((response) => response ? writeResponseToNodeResponse(response, res) : next())
+            .catch(next);
+        });
+        return server;
+      }
+
+      const server = app();
+
+      if (isMainModule(import.meta.url)) {
+        const port = process.env['PORT'] || 4000;
+        server.listen(port, (error) => {
+          if (error) {
+            throw error;
+          }
+          console.log(\`Node Express server listening on http://localhost:\${port}\`);
+        });
+      }
+
+      export const reqHandler = createNodeRequestHandler(server);
+    `,
+  });
+
+  await silentNg('generate', 'component', 'home');
+
+  await noSilentNg('build', '--output-mode=static');
+
+  for (const { lang, outputPath } of langTranslations) {
+    const contents = await readFile(join(outputPath, 'home/index.html'));
+    match(contents, /<p>{[\S\s]*"dataFromAssets":[\s\S]*true[\S\s]*}<\/p>/);
+    match(contents, /<p>{[\S\s]*"dataFromAPI":[\s\S]*true[\S\s]*}<\/p>/);
+    match(contents, new RegExp(`<base href="\\/${lang}\\/">`));
+  }
+}