fix(@angular/ssr): resolve circular dependency issue from main.server.js reference in manifest

The issue was addressed by changing the top-level import to a dynamic import.

Closes #28358

Author: alan-agius4

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

@@ -89,17 +89,15 @@ export function generateAngularServerAppManifest(
     if (
       file.path === INDEX_HTML_SERVER ||
       file.path === INDEX_HTML_CSR ||
-      file.path.endsWith('.css')
+      (inlineCriticalCss && file.path.endsWith('.css'))
     ) {
       serverAssetsContent.push(`['${file.path}', async () => ${JSON.stringify(file.text)}]`);
     }
   }
 
   const manifestContent = `
-import bootstrap from './main.server.mjs';
-
 export default {
-  bootstrap: () => bootstrap,
+  bootstrap: () => import('./main.server.mjs').then(m => m.default),
   inlineCriticalCss: ${inlineCriticalCss},
   routes: ${JSON.stringify(routes, undefined, 2)},
   assets: new Map([${serverAssetsContent.join(', \n')}]),

packages/angular/ssr/src/app.ts

@@ -15,7 +15,7 @@ import { getAngularAppManifest } from './manifest';
 import { ServerRouter } from './routes/router';
 import { REQUEST, REQUEST_CONTEXT, RESPONSE_INIT } from './tokens';
 import { InlineCriticalCssProcessor } from './utils/inline-critical-css';
-import { renderAngular } from './utils/ng';
+import { AngularBootstrap, renderAngular } from './utils/ng';
 
 /**
  * Enum representing the different contexts in which server rendering can occur.
@@ -58,6 +58,11 @@ export class AngularServerApp {
    */
   private inlineCriticalCssProcessor: InlineCriticalCssProcessor | undefined;
 
+  /**
+   * The bootstrap mechanism for the server application.
+   */
+  private boostrap: AngularBootstrap | undefined;
+
   /**
    * Renders a response for the given HTTP request using the server application.
    *
@@ -176,7 +181,9 @@ export class AngularServerApp {
       html = await hooks.run('html:transform:pre', { html });
     }
 
-    html = await renderAngular(html, manifest.bootstrap(), new URL(request.url), platformProviders);
+    this.boostrap ??= await manifest.bootstrap();
+
+    html = await renderAngular(html, this.boostrap, new URL(request.url), platformProviders);
 
     if (manifest.inlineCriticalCss) {
       // Optionally inline critical CSS.

packages/angular/ssr/src/manifest.ts

@@ -71,9 +71,10 @@ export interface AngularAppManifest {
 
   /**
    * The bootstrap mechanism for the server application.
-   * A function that returns a reference to an NgModule or a function returning a promise that resolves to an ApplicationRef.
+   * A function that returns a promise that resolves to an `NgModule` or a function
+   * returning a promise that resolves to an `ApplicationRef`.
    */
-  readonly bootstrap: () => AngularBootstrap;
+  readonly bootstrap: () => Promise<AngularBootstrap>;
 
   /**
    * Indicates whether critical CSS should be inlined into the HTML.

packages/angular/ssr/src/routes/ng-routes.ts

@@ -274,7 +274,7 @@ export async function extractRoutesAndCreateRouteTree(
   const routeTree = new RouteTree();
   const document = await new ServerAssets(manifest).getIndexServerHtml();
   const { baseHref, routes } = await getRoutesFromAngularRouterConfig(
-    manifest.bootstrap(),
+    await manifest.bootstrap(),
     document,
     url,
   );

packages/angular/ssr/test/testing-utils.ts

@@ -38,7 +38,7 @@ export function setAngularAppTestingManifest(routes: Routes, baseHref = ''): voi
 </html>`,
       }),
     ),
-    bootstrap: () => () => {
+    bootstrap: async () => () => {
       @Component({
         standalone: true,
         selector: 'app-root',

tests/legacy-cli/e2e/tests/build/ssr/express-engine-csp-nonce.ts

@@ -136,25 +136,30 @@ export default async function () {
       `,
   });
 
-  async function ngDevSsr(): Promise<number> {
+  async function spawnServer(): Promise<number> {
     const port = await findFreePort();
-    const useWebpackBuilder = !getGlobalVariable('argv')['esbuild'];
-    const validBundleRegEx = useWebpackBuilder ? /Compiled successfully\./ : /complete\./;
+
+    const runCommand = useWebpackBuilder ? 'serve:ssr' : 'serve:ssr:test-project';
 
     await execAndWaitForOutputToMatch(
-      'ng',
-      [
-        'run',
-        `test-project:${useWebpackBuilder ? 'serve-ssr' : 'serve'}:production`,
-        '--port',
-        String(port),
-      ],
-      validBundleRegEx,
+      'npm',
+      ['run', runCommand],
+      /Node Express server listening on/,
+      {
+        'PORT': String(port),
+      },
     );
 
     return port;
   }
 
-  const port = await ngDevSsr();
+  await ng('build');
+
+  if (useWebpackBuilder) {
+    // Build server code
+    await ng('run', 'test-project:server');
+  }
+
+  const port = await spawnServer();
   await ng('e2e', `--base-url=http://localhost:${port}`, '--dev-server-target=');
 }

tests/legacy-cli/e2e/tests/build/ssr/express-engine-ngmodule.ts

@@ -141,28 +141,34 @@ export default async function () {
       `,
   });
 
-  async function ngDevSsr(): Promise<number> {
+  async function spawnServer(): Promise<number> {
     const port = await findFreePort();
-    const validBundleRegEx = useWebpackBuilder ? /Compiled successfully\./ : /complete\./;
+
+    const runCommand = useWebpackBuilder ? 'serve:ssr' : `serve:ssr:test-project-two`;
 
     await execAndWaitForOutputToMatch(
-      'ng',
-      [
-        'run',
-        `test-project-two:${useWebpackBuilder ? 'serve-ssr' : 'serve'}:production`,
-        '--port',
-        String(port),
-      ],
-      validBundleRegEx,
+      'npm',
+      ['run', runCommand],
+      /Node Express server listening on/,
+      {
+        'PORT': String(port),
+      },
     );
 
     return port;
   }
 
-  const port = await ngDevSsr();
+  await ng('build', 'test-project-two');
+
+  if (useWebpackBuilder) {
+    // Build server code
+    await ng('run', `test-project-two:server`);
+  }
+
+  const port = await spawnServer();
   await ng(
     'e2e',
-    'test-project-two',
+    '--project=test-project-two',
     `--base-url=http://localhost:${port}`,
     '--dev-server-target=',
   );

tests/legacy-cli/e2e/tests/build/ssr/express-engine-standalone.ts

@@ -106,24 +106,28 @@ export default async function () {
       `,
   });
 
-  async function ngDevSsr(): Promise<number> {
+  async function spawnServer(): Promise<number> {
     const port = await findFreePort();
-    const validBundleRegEx = useWebpackBuilder ? /Compiled successfully\./ : /complete\./;
+    const runCommand = useWebpackBuilder ? 'serve:ssr' : 'serve:ssr:test-project';
 
     await execAndWaitForOutputToMatch(
-      'ng',
-      [
-        'run',
-        `test-project:${useWebpackBuilder ? 'serve-ssr' : 'serve'}:production`,
-        '--port',
-        String(port),
-      ],
-      validBundleRegEx,
+      'npm',
+      ['run', runCommand],
+      /Node Express server listening on/,
+      {
+        'PORT': String(port),
+      },
     );
 
     return port;
   }
 
-  const port = await ngDevSsr();
+  await ng('build');
+  if (useWebpackBuilder) {
+    // Build server code
+    await ng('run', `test-project:server`);
+  }
+
+  const port = await spawnServer();
   await ng('e2e', `--base-url=http://localhost:${port}`, '--dev-server-target=');
 }