From ad80e2b07231c6fd0d004ecdec55de76da748b6a Mon Sep 17 00:00:00 2001
From: Alan Agius <17563226+alan-agius4@users.noreply.github.com>
Date: Fri, 16 Oct 2026 07:40:33 +0000
Subject: [PATCH] fix(@angular/build): align lazy route entry names with
 workspace root for SSR modulepreload
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Override `compilerOptions.basePath` with `build.initialOptions.absWorkingDir` when initializing the Angular compilation so `lazyRoutesTransformer` computes `ɵentryName` relative to the workspace root rather than the tsconfig directory. This matches the workspace-relative keys in `entryPointToBrowserMapping` used for SSR `modulepreload` link generation when the application's `tsconfig` is not located at the workspace root.

Closes #34369
---
 .../behavior/chunk-optimization-server_spec.ts   | 16 ++++++++++------
 .../compilation/angular-compilation_spec.ts      |  8 +++++++-
 .../angular/compilation/compiler-options.ts      |  2 ++
 .../src/tools/esbuild/angular/compiler-plugin.ts |  1 +
 4 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/packages/angular/build/src/builders/application/tests/behavior/chunk-optimization-server_spec.ts b/packages/angular/build/src/builders/application/tests/behavior/chunk-optimization-server_spec.ts
index 76ecbbc4329e..18b92e7690a0 100644
--- a/packages/angular/build/src/builders/application/tests/behavior/chunk-optimization-server_spec.ts
+++ b/packages/angular/build/src/builders/application/tests/behavior/chunk-optimization-server_spec.ts
@@ -151,15 +151,19 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
         .not.toBeNull();
 
       const mapping = JSON.parse(mappingSource![1]) as Record<string, string[]>;
+      const mainServerContent = harness.readFile('dist/server/main.server.mjs');
 
-      // Every lazy route entry point must retain a mapping entry after optimization.
+      // Every lazy route entry point must retain a mapping entry after optimization
+      // that matches the ɵentryName emitted into the server bundle.
       for (const name of LAZY_ROUTE_NAMES) {
-        const key = Object.keys(mapping).find((entryPoint) =>
-          entryPoint.endsWith(`${name}.component.ts`),
-        );
-        expect(key)
-          .withContext(`mapping entry for lazy route '${name}' should exist`)
+        const expectedEntryPoint = `src/app/${name}.component.ts`;
+        expect(mapping[expectedEntryPoint])
+          .withContext(`mapping entry for '${expectedEntryPoint}' should exist`)
           .toBeDefined();
+
+        expect(mainServerContent)
+          .withContext(`main.server.mjs should contain ɵentryName '${expectedEntryPoint}'`)
+          .toContain(expectedEntryPoint);
       }
 
       // Every browser file referenced by the mapping must exist on disk.
diff --git a/packages/angular/build/src/tools/angular/compilation/angular-compilation_spec.ts b/packages/angular/build/src/tools/angular/compilation/angular-compilation_spec.ts
index 71eacd562259..0499431fe2c9 100644
--- a/packages/angular/build/src/tools/angular/compilation/angular-compilation_spec.ts
+++ b/packages/angular/build/src/tools/angular/compilation/angular-compilation_spec.ts
@@ -326,7 +326,11 @@ describe('AngularCompilation', () => {
     it('applies override options correctly', () => {
       const { compilerOptions } = transformCompilerOptions(
         ts,
-        { target: ts.ScriptTarget.ES2022, isolatedModules: true },
+        {
+          target: ts.ScriptTarget.ES2022,
+          isolatedModules: true,
+          basePath: '/workspace/projects/app',
+        },
         {
           sourcemap: true,
           preserveSymlinks: true,
@@ -334,9 +338,11 @@ describe('AngularCompilation', () => {
           enableHmr: true,
           instrumentForCoverage: true,
           includeTestMetadata: true,
+          basePath: '/workspace',
         },
       );
 
+      expect(compilerOptions.basePath).toBe('/workspace');
       expect(compilerOptions.inlineSources).toBe(true);
       expect(compilerOptions.inlineSourceMap).toBe(true);
       expect(compilerOptions.preserveSymlinks).toBe(true);
diff --git a/packages/angular/build/src/tools/angular/compilation/compiler-options.ts b/packages/angular/build/src/tools/angular/compilation/compiler-options.ts
index 45af80eae6d3..81ef9425b610 100644
--- a/packages/angular/build/src/tools/angular/compilation/compiler-options.ts
+++ b/packages/angular/build/src/tools/angular/compilation/compiler-options.ts
@@ -21,6 +21,7 @@ export interface CompilerOptionOverrides {
   includeTestMetadata?: boolean;
   customConditions?: string[];
   rootFiles?: string[];
+  basePath?: string;
 }
 
 export function transformCompilerOptions(
@@ -113,6 +114,7 @@ export function transformCompilerOptions(
   return {
     compilerOptions: {
       ...compilerOptions,
+      basePath: overrides?.basePath ?? compilerOptions.basePath,
       noEmitOnError: false,
       composite: false,
       inlineSources: !!overrides?.sourcemap,
diff --git a/packages/angular/build/src/tools/esbuild/angular/compiler-plugin.ts b/packages/angular/build/src/tools/esbuild/angular/compiler-plugin.ts
index 9a36eea56d61..cd53d6085e65 100644
--- a/packages/angular/build/src/tools/esbuild/angular/compiler-plugin.ts
+++ b/packages/angular/build/src/tools/esbuild/angular/compiler-plugin.ts
@@ -331,6 +331,7 @@ export function createCompilerPlugin(
               includeTestMetadata: !!pluginOptions.includeTestMetadata,
               customConditions: build.initialOptions.conditions,
               rootFiles: pluginOptions.rootFiles,
+              basePath: build.initialOptions.absWorkingDir,
             },
           );