[8.x] Check for incomplete class to prevent unexpected error when class cannot be loaded (#38379)

* Check for incomplete class to prevent unexpected error when class cannot be loaded

* Check for incomplete class to prevent unexpected error when class cannot be loaded (style)

* Update RetryCommand.php

Co-authored-by: Christoph Beyer <the-real-christoph>
Co-authored-by: Taylor Otwell <[email protected]>

Author: the-real-christoph

src/Illuminate/Queue/Console/RetryCommand.php

@@ -171,7 +171,7 @@ protected function refreshRetryUntil($payload)
             throw new RuntimeException('Unable to extract job payload.');
         }
 
-        if (is_object($instance) && method_exists($instance, 'retryUntil')) {
+        if (is_object($instance) && ! $instance instanceof \__PHP_Incomplete_Class && method_exists($instance, 'retryUntil')) {
             $retryUntil = $instance->retryUntil();
 
             $payload['retryUntil'] = $retryUntil instanceof DateTimeInterface