A person who is sued may respond by filing their own claim against the party that started the lawsuit. The claims are usually related, for example a builder may sue a homeowner for unpaid work but the homeowner may counterclaim for damages done to their property by the builder. The court will then deal with both these claims at the same time.
Error message
Deprecated function: rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in Drupal\advagg_mod\EventSubscriber\InitSubscriber->onEvent() (line 130 of modules/contrib/advagg/advagg_mod/src/EventSubscriber/InitSubscriber.php).
Drupal\advagg_mod\EventSubscriber\InitSubscriber->onEvent(Object, 'kernel.request', Object) call_user_func(Array, Object, 'kernel.request', Object) (Line: 142) Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.request') (Line: 145) Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81) Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58) Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48) Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 191) Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 128) Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 82) Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48) Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51) Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23) Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 718) Drupal\Core\DrupalKernel->handle(Object) (Line: 19)