[Translation] deprecate the backup feature

UPGRADE-3.1.md

@@ -72,6 +72,12 @@ Serializer
    deprecated and will not be supported in Symfony 4.0. You should use the
    `CacheClassMetadataFactory` class instead.
 
+Translation
+-----------
+
+ * Deprecated the backup feature of the file dumper classes. It will be removed
+   in Symfony 4.0.
+
 Yaml
 ----
 

UPGRADE-4.0.md

@@ -68,6 +68,11 @@ Serializer
    class has been removed. You should use the `CacheClassMetadataFactory` class
    instead.
 
+Translation
+-----------
+
+ * Removed the backup feature from the file dumper classes.
+
 Yaml
 ----
 

src/Symfony/Component/Translation/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+3.1.0
+-----
+
+ * Deprecated the backup feature of the file dumper classes.
+
 3.0.0
 -----
 

src/Symfony/Component/Translation/Dumper/FileDumper.php

@@ -73,6 +73,7 @@ abstract class FileDumper implements DumperInterface
             $fullpath = $options['path'].'/'.$this->getRelativePath($domain, $messages->getLocale());
             if (file_exists($fullpath)) {
                 if ($this->backup) {
+                    @trigger_error('Creating a backup while dumping a message catalogue is deprecated since version 3.1 and will be removed in 4.0. Use TranslationWriter::disableBackup() to disable the backup.', E_USER_DEPRECATED);
                     copy($fullpath, $fullpath.'~');
                 }
             } else {

src/Symfony/Component/Translation/Tests/Dumper/FileDumperTest.php

@@ -29,6 +29,9 @@ class FileDumperTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue(file_exists($tempDir.'/messages.en.concrete'));
     }
 
+    /**
+     * @group legacy
+     */
     public function testDumpBackupsFileIfExisting()
     {
         $tempDir = sys_get_temp_dir();