Do not add the same tag multiple times (#423)

Do not add the same tag multiple times

Author: Toflar

CHANGELOG.md

@@ -10,6 +10,10 @@ See also the [GitHub releases page](https://github.com/FriendsOfSymfony/FOSHttpC
 
 * Added: `CleanupCacheTagsListener` to remove the cache tags header from the final
   response that is sent to the client. Add this listener to your cache kernel.
+  
+### Tagging
+
+* Improved: The `ResponseTagger` does now remove duplicate tags.
 
 2.3.1
 -----

src/ResponseTagger.php

@@ -123,7 +123,7 @@ public function addTags(array $tags)
             throw new InvalidTagException('Empty tags are not allowed');
         }
 
-        $this->tags = array_merge($this->tags, $filtered);
+        $this->tags = array_unique(array_merge($this->tags, $filtered));
 
         return $this;
     }

tests/Unit/ResponseTaggerTest.php

@@ -132,4 +132,16 @@ public function testNonStrictEmptyTag()
         $this->assertTrue($tagHandler->hasTags());
         $this->assertEquals('post-1', $tagHandler->getTagsHeaderValue());
     }
+
+    public function testUniqueTags()
+    {
+        $headerFormatter = new CommaSeparatedTagHeaderFormatter('FOS-Tags');
+
+        $tagHandler = new ResponseTagger(['header_formatter' => $headerFormatter, 'strict' => true]);
+        $tagHandler->addTags(['post-1', 'post-2', 'post-1']);
+        $tagHandler->addTags(['post-2', 'post-3']);
+        $this->assertTrue($tagHandler->hasTags());
+
+        $this->assertEquals('post-1,post-2,post-3', $tagHandler->getTagsHeaderValue());
+    }
 }