Merge branch '3.4' into 4.1

* 3.4:
  Fix CS
  Allow reuse of Session between requests
  [MonologBridge] Re-add option option to ignore empty context and extra data
  [Lock] remove useless code
  [PhpUnitBridge] fix disabling DeprecationErrorHandler using phpunit.xml file
  Provide debug_backtrace with proper args
  [DI] fix infinite loop involving self-references in decorated services
  forward false label option to nested types
  forward the invalid_message option in date types

Author: nicolas-grekas

DeprecationErrorHandler.php

@@ -54,7 +54,11 @@ public static function register($mode = 0)
             if (false === $mode) {
                 $mode = getenv('SYMFONY_DEPRECATIONS_HELPER');
             }
-            if (DeprecationErrorHandler::MODE_WEAK !== $mode && DeprecationErrorHandler::MODE_WEAK_VENDORS !== $mode && (!isset($mode[0]) || '/' !== $mode[0])) {
+            if (DeprecationErrorHandler::MODE_DISABLED !== $mode
+                && DeprecationErrorHandler::MODE_WEAK !== $mode
+                && DeprecationErrorHandler::MODE_WEAK_VENDORS !== $mode
+                && (!isset($mode[0]) || '/' !== $mode[0])
+            ) {
                 $mode = preg_match('/^[1-9][0-9]*$/', $mode) ? (int) $mode : 0;
             }
 
@@ -108,7 +112,7 @@ public static function register($mode = 0)
                 return $ErrorHandler::handleError($type, $msg, $file, $line, $context);
             }
 
-            $trace = debug_backtrace(true);
+            $trace = debug_backtrace();
             $group = 'other';
             $isVendor = DeprecationErrorHandler::MODE_WEAK_VENDORS === $mode && $inVendors($file);