Merge branch '5.4' into 6.0

* 5.4:
  [DependencyInjection] Add `SubscribedService` attribute, deprecate current `ServiceSubscriberTrait` usage
  Use try/finally to restore error handlers
  Allow serializer default context configuration

Author: nicolas-grekas

Store/FlockStore.php

@@ -106,15 +106,18 @@ private function lock(Key $key, bool $read, bool $blocking)
 
             // Silence error reporting
             set_error_handler(function ($type, $msg) use (&$error) { $error = $msg; });
-            if (!$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r')) {
-                if ($handle = fopen($fileName, 'x')) {
-                    chmod($fileName, 0666);
-                } elseif (!$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r')) {
-                    usleep(100); // Give some time for chmod() to complete
-                    $handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r');
+            try {
+                if (!$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r')) {
+                    if ($handle = fopen($fileName, 'x')) {
+                        chmod($fileName, 0666);
+                    } elseif (!$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r')) {
+                        usleep(100); // Give some time for chmod() to complete
+                        $handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r');
+                    }
                 }
+            } finally {
+                restore_error_handler();
             }
-            restore_error_handler();
         }
 
         if (!$handle) {