fix(@angular-devkit/build-angular): fail browser build when index gen…

…eration fails

Currently, when there is an error during index generation this is just been logged in the console.

(cherry picked from commit c65b049)

packages/angular_devkit/build_angular/src/browser/index.ts

@@ -648,6 +648,7 @@ export function buildWebpackBrowser(
                     postTransform: transforms.indexHtml,
                   });
 
+                  let hasErrors = false;
                   for (const [locale, outputPath] of outputPaths.entries()) {
                     try {
                       const { content, warnings, errors } = await indexHtmlGenerator.process({
@@ -663,7 +664,10 @@ export function buildWebpackBrowser(
                       if (warnings.length || errors.length) {
                         spinner.stop();
                         warnings.forEach((m) => context.logger.warn(m));
-                        errors.forEach((m) => context.logger.error(m));
+                        errors.forEach((m) => {
+                          context.logger.error(m);
+                          hasErrors = true;
+                        });
                         spinner.start();
                       }
 
@@ -677,7 +681,13 @@ export function buildWebpackBrowser(
                     }
                   }
 
-                  spinner.succeed('Index html generation complete.');
+                  if (hasErrors) {
+                    spinner.fail('Index html generation failed.');
+
+                    return { success: false };
+                  } else {
+                    spinner.succeed('Index html generation complete.');
+                  }
                 }
 
                 if (options.serviceWorker) {