fix(@angular/build): ensure correct handling of index.output for SSR

packages/angular/build/src/builders/application/options.ts

@@ -327,24 +327,26 @@ export async function normalizeOptions(
     let indexOutput: string;
     // The output file will be created within the configured output path
     if (typeof options.index === 'string') {
-      /**
-       * If SSR is activated, create a distinct entry file for the `index.html`.
-       * This is necessary because numerous server/cloud providers automatically serve the `index.html` as a static file
-       * if it exists (handling SSG).
-       *
-       * For instance, accessing `foo.com/` would lead to `foo.com/index.html` being served instead of hitting the server.
-       *
-       * This approach can also be applied to service workers, where the `index.csr.html` is served instead of the prerendered `index.html`.
-       */
-      const indexBaseName = path.basename(options.index);
-      indexOutput =
-        (ssrOptions || prerenderOptions) && indexBaseName === 'index.html'
-          ? INDEX_HTML_CSR
-          : indexBaseName;
+      indexOutput = options.index;
     } else {
       indexOutput = options.index.output || 'index.html';
     }
 
+    /**
+     * If SSR is activated, create a distinct entry file for the `index.html`.
+     * This is necessary because numerous server/cloud providers automatically serve the `index.html` as a static file
+     * if it exists (handling SSG).
+     *
+     * For instance, accessing `foo.com/` would lead to `foo.com/index.html` being served instead of hitting the server.
+     *
+     * This approach can also be applied to service workers, where the `index.csr.html` is served instead of the prerendered `index.html`.
+     */
+    const indexBaseName = path.basename(indexOutput);
+    indexOutput =
+      (ssrOptions || prerenderOptions) && indexBaseName === 'index.html'
+        ? INDEX_HTML_CSR
+        : indexBaseName;
+
     indexHtmlOptions = {
       input: path.join(
         workspaceRoot,

packages/angular/build/src/builders/application/tests/behavior/index-csr_spec.ts

@@ -0,0 +1,57 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+import { buildApplication } from '../../index';
+import { APPLICATION_BUILDER_INFO, BASE_OPTIONS, describeBuilder } from '../setup';
+
+describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
+  describe('Behavior: "index.csr.html"', () => {
+    beforeEach(async () => {
+      await harness.modifyFile('src/tsconfig.app.json', (content) => {
+        const tsConfig = JSON.parse(content);
+        tsConfig.files ??= [];
+        tsConfig.files.push('main.server.ts');
+
+        return JSON.stringify(tsConfig);
+      });
+    });
+
+    it(`should generate 'index.csr.html' instead of 'index.html' when ssr is enabled.`, async () => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        server: 'src/main.server.ts',
+        ssr: true,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+      harness.expectDirectory('dist/server').toExist();
+      harness.expectFile('dist/browser/index.csr.html').toExist();
+      harness.expectFile('dist/browser/index.html').toNotExist();
+    });
+
+    it(`should generate 'index.csr.html' instead of 'index.html' when 'output' is 'index.html' and ssr is enabled.`, async () => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        index: {
+          input: 'src/index.html',
+          output: 'index.html',
+        },
+        server: 'src/main.server.ts',
+        ssr: true,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+
+      harness.expectDirectory('dist/server').toExist();
+      harness.expectFile('dist/browser/index.csr.html').toExist();
+      harness.expectFile('dist/browser/index.html').toNotExist();
+    });
+  });
+});

packages/angular/build/src/builders/application/tests/options/index_spec.ts

@@ -12,7 +12,6 @@ import { APPLICATION_BUILDER_INFO, BASE_OPTIONS, describeBuilder } from '../setu
 describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
   describe('Option: "index"', () => {
     beforeEach(async () => {
-      // Application code is not needed for index tests
       await harness.writeFile('src/main.ts', 'console.log("TEST");');
     });
 
@@ -140,92 +139,72 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
       });
     });
 
-    it('should generate initial preload link elements when preloadInitial is true', async () => {
-      harness.useTarget('build', {
-        ...BASE_OPTIONS,
-        index: {
-          input: 'src/index.html',
-          preloadInitial: true,
-        },
-      });
-
-      // Setup an initial chunk usage for JS
-      await harness.writeFile('src/a.ts', 'console.log("TEST");');
-      await harness.writeFile('src/b.ts', 'import "./a";');
-      await harness.writeFile('src/main.ts', 'import "./a";\n(() => import("./b"))();');
+    describe('preload', () => {
+      it('should generate initial preload link elements when preloadInitial is true', async () => {
+        harness.useTarget('build', {
+          ...BASE_OPTIONS,
+          index: {
+            input: 'src/index.html',
+            preloadInitial: true,
+          },
+        });
 
-      const { result } = await harness.executeOnce();
+        // Setup an initial chunk usage for JS
+        await harness.writeFile('src/a.ts', 'console.log("TEST");');
+        await harness.writeFile('src/b.ts', 'import "./a";');
+        await harness.writeFile('src/main.ts', 'import "./a";\n(() => import("./b"))();');
 
-      expect(result?.success).toBe(true);
-      harness.expectFile('dist/browser/main.js').content.toContain('chunk-');
-      harness.expectFile('dist/browser/index.html').content.toContain('modulepreload');
-      harness.expectFile('dist/browser/index.html').content.toContain('chunk-');
-    });
+        const { result } = await harness.executeOnce();
 
-    it('should generate initial preload link elements when preloadInitial is undefined', async () => {
-      harness.useTarget('build', {
-        ...BASE_OPTIONS,
-        index: {
-          input: 'src/index.html',
-          preloadInitial: undefined,
-        },
+        expect(result?.success).toBe(true);
+        harness.expectFile('dist/browser/main.js').content.toContain('chunk-');
+        harness.expectFile('dist/browser/index.html').content.toContain('modulepreload');
+        harness.expectFile('dist/browser/index.html').content.toContain('chunk-');
       });
 
-      // Setup an initial chunk usage for JS
-      await harness.writeFile('src/a.ts', 'console.log("TEST");');
-      await harness.writeFile('src/b.ts', 'import "./a";');
-      await harness.writeFile('src/main.ts', 'import "./a";\n(() => import("./b"))();');
+      it('should generate initial preload link elements when preloadInitial is undefined', async () => {
+        harness.useTarget('build', {
+          ...BASE_OPTIONS,
+          index: {
+            input: 'src/index.html',
+            preloadInitial: undefined,
+          },
+        });
 
-      const { result } = await harness.executeOnce();
+        // Setup an initial chunk usage for JS
+        await harness.writeFile('src/a.ts', 'console.log("TEST");');
+        await harness.writeFile('src/b.ts', 'import "./a";');
+        await harness.writeFile('src/main.ts', 'import "./a";\n(() => import("./b"))();');
 
-      expect(result?.success).toBe(true);
-      harness.expectFile('dist/browser/main.js').content.toContain('chunk-');
-      harness.expectFile('dist/browser/index.html').content.toContain('modulepreload');
-      harness.expectFile('dist/browser/index.html').content.toContain('chunk-');
-    });
+        const { result } = await harness.executeOnce();
 
-    it('should not generate initial preload link elements when preloadInitial is false', async () => {
-      harness.useTarget('build', {
-        ...BASE_OPTIONS,
-        index: {
-          input: 'src/index.html',
-          preloadInitial: false,
-        },
+        expect(result?.success).toBe(true);
+        harness.expectFile('dist/browser/main.js').content.toContain('chunk-');
+        harness.expectFile('dist/browser/index.html').content.toContain('modulepreload');
+        harness.expectFile('dist/browser/index.html').content.toContain('chunk-');
       });
 
-      // Setup an initial chunk usage for JS
-      await harness.writeFile('src/a.ts', 'console.log("TEST");');
-      await harness.writeFile('src/b.ts', 'import "./a";');
-      await harness.writeFile('src/main.ts', 'import "./a";\n(() => import("./b"))();');
-
-      const { result } = await harness.executeOnce();
-
-      expect(result?.success).toBe(true);
-      harness.expectFile('dist/browser/main.js').content.toContain('chunk-');
-      harness.expectFile('dist/browser/index.html').content.not.toContain('modulepreload');
-      harness.expectFile('dist/browser/index.html').content.not.toContain('chunk-');
-    });
+      it('should not generate initial preload link elements when preloadInitial is false', async () => {
+        harness.useTarget('build', {
+          ...BASE_OPTIONS,
+          index: {
+            input: 'src/index.html',
+            preloadInitial: false,
+          },
+        });
 
-    it(`should generate 'index.csr.html' instead of 'index.html' by default when ssr is enabled.`, async () => {
-      await harness.modifyFile('src/tsconfig.app.json', (content) => {
-        const tsConfig = JSON.parse(content);
-        tsConfig.files ??= [];
-        tsConfig.files.push('main.server.ts');
+        // Setup an initial chunk usage for JS
+        await harness.writeFile('src/a.ts', 'console.log("TEST");');
+        await harness.writeFile('src/b.ts', 'import "./a";');
+        await harness.writeFile('src/main.ts', 'import "./a";\n(() => import("./b"))();');
 
-        return JSON.stringify(tsConfig);
-      });
+        const { result } = await harness.executeOnce();
 
-      harness.useTarget('build', {
-        ...BASE_OPTIONS,
-        server: 'src/main.server.ts',
-        ssr: true,
+        expect(result?.success).toBe(true);
+        harness.expectFile('dist/browser/main.js').content.toContain('chunk-');
+        harness.expectFile('dist/browser/index.html').content.not.toContain('modulepreload');
+        harness.expectFile('dist/browser/index.html').content.not.toContain('chunk-');
       });
-
-      const { result } = await harness.executeOnce();
-      expect(result?.success).toBeTrue();
-      harness.expectDirectory('dist/server').toExist();
-      harness.expectFile('dist/browser/index.csr.html').toExist();
-      harness.expectFile('dist/browser/index.html').toNotExist();
     });
   });
 });