From 0b6ebb2b02f734aa277ad4bf64c15a831bea857c Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Tue, 26 Aug 2025 20:41:14 -0400
Subject: [PATCH] fix(@angular/build): ensure karma polyfills reporter factory
 returns a value

The factory function for the `reporter:angular--polyfills` Karma plugin did not return a value, which violates Karma's plugin contract. This could cause Karma to crash when multiple reporters were in use, particularly with tools that use Karma's multi-reporter functionality.

This change modifies the factory to return an object with an empty `adapters` array (`{ adapters: [] }`). This satisfies Karma's plugin requirements and ensures compatibility with the multi-reporter, preventing the crash.

Fixes #31039
---
 .../angular/build/src/builders/karma/application_builder.ts    | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/angular/build/src/builders/karma/application_builder.ts b/packages/angular/build/src/builders/karma/application_builder.ts
index ae238b7239cf..004c46930ff9 100644
--- a/packages/angular/build/src/builders/karma/application_builder.ts
+++ b/packages/angular/build/src/builders/karma/application_builder.ts
@@ -187,6 +187,9 @@ class AngularPolyfillsPlugin {
             included: true,
             watched: false,
           });
+
+          // Karma needs a return value for a factory and Karma's multi-reporter expects an `adapters` array
+          return { adapters: [] };
         }, AngularPolyfillsPlugin),
       ],
     };