Merge branch '2.6' into 2.7

* 2.6:
  [Routing][DependencyInjection] Support .yaml extension in YAML loaders
  [DX] improve file loader error for router/other resources in bundle
  [FrameworkBundle] Initialize translator with the default locale.
  [FrameworkBundle] Fix Routing\DelegatingLoader resiliency to fatal errors
  [2.6][Translation] remove duplicate code for loading catalogue.
  [HttpKernel] Cleanup ExceptionListener
  CS fixes
  [DependencyInjection] Show better error when the Yaml component is not installed
  [2.3] SCA for Components - reference mismatches
  [Debug] Scream as LogLevel::DEBUG (but for fatal errors / uncaught exceptions)
  [2.3] Static Code Analysis for Components
  [WebProfilerBundle] Fix resiliency to exceptions thrown by the url generator
  [Translation] LoggingTranslator simplifications
  [Translation][fixed test] refresh cache when resources are no longer fresh.
  [FrameworkBundle] Fixed server:start --router relative path issue #14124
  [FrameworkBundle] improve usage of Table helper
  [Validator] Added missing Simplified Chinese (zh_CN) translations
  [FrameworkBundle] Workaround php -S ignoring auto_prepend_file

Conflicts:
	src/Symfony/Bundle/FrameworkBundle/Tests/Translation/TranslatorTest.php
	src/Symfony/Component/Console/Helper/Table.php
	src/Symfony/Component/Translation/LoggingTranslator.php

Author: nicolas-grekas

Extension/Core/DataTransformer/BaseDateTimeTransformer.php

@@ -40,11 +40,11 @@ abstract class BaseDateTimeTransformer implements DataTransformerInterface
      */
     public function __construct($inputTimezone = null, $outputTimezone = null)
     {
-        if (!is_string($inputTimezone) && null !== $inputTimezone) {
+        if (null !== $inputTimezone && !is_string($inputTimezone)) {
             throw new UnexpectedTypeException($inputTimezone, 'string');
         }
 
-        if (!is_string($outputTimezone) && null !== $outputTimezone) {
+        if (null !== $outputTimezone && !is_string($outputTimezone)) {
             throw new UnexpectedTypeException($outputTimezone, 'string');
         }
 

Extension/Core/DataTransformer/DateTimeToArrayTransformer.php

@@ -99,6 +99,8 @@ public function transform($dateTime)
                 // remove leading zeros
                 $entry = (string) (int) $entry;
             }
+            // unset reference to keep scope clear
+            unset($entry);
         }
 
         return $result;

Extension/Core/EventListener/MergeCollectionListener.php

@@ -74,7 +74,7 @@ public function onSubmit(FormEvent $event)
         }
 
         // If we are not allowed to change anything, return immediately
-        if ((!$this->allowAdd && !$this->allowDelete) || $data === $dataToMergeInto) {
+        if ($data === $dataToMergeInto || (!$this->allowAdd && !$this->allowDelete)) {
             $event->setData($dataToMergeInto);
 
             return;