fix(@angular-devkit/build-angular): provide better error messages for failed file reads

This commit adds a more actionable error message when `readFile` fails during index generation.

Author: alan-agius4

packages/angular_devkit/build_angular/src/utils/index-file/index-html-generator.ts

@@ -6,8 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import * as fs from 'fs';
-import { join } from 'path';
+import { readFile } from 'node:fs/promises';
+import { join } from 'node:path';
 import { NormalizedCachedOptions } from '../normalize-cache';
 import { NormalizedOptimizationOptions } from '../normalize-optimization';
 import { stripBom } from '../strip-bom';
@@ -104,11 +104,19 @@ export class IndexHtmlGenerator {
   }
 
   async readAsset(path: string): Promise<string> {
-    return fs.promises.readFile(path, 'utf-8');
+    try {
+      return await readFile(path, 'utf-8');
+    } catch {
+      throw new Error(`Failed to read asset "${path}".`);
+    }
   }
 
   protected async readIndex(path: string): Promise<string> {
-    return fs.promises.readFile(path, 'utf-8');
+    try {
+      return await readFile(path, 'utf-8');
+    } catch {
+      throw new Error(`Failed to read index HTML file "${path}".`);
+    }
   }
 }
 

packages/schematics/angular/migrations/update-17/use-application-builder.ts

@@ -57,6 +57,10 @@ export default function (): Rule {
           continue;
         }
 
+        if (options['index'] === '') {
+          options['index'] = false;
+        }
+
         // Rename and transform options
         options['browser'] = options['main'];
         if (hasServerTarget && typeof options['browser'] === 'string') {