bug #24490 [HttpFoundation] Combine Cache-Control headers (c960657)

This PR was merged into the 2.7 branch.

Discussion
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[HttpFoundation] Combine Cache-Control headers

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

If multiple `Cache-Control` headers are added to a `ResponseHeaderBag`, only the first is returned by `$bag->get('Cache-Control')`.

Commits
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1f76a70 [HttpFoundation] Combine Cache-Control headers

src/Symfony/Component/HttpFoundation/HeaderBag.php

@@ -146,7 +146,7 @@ public function set($key, $values, $replace = true)
         }
 
         if ('cache-control' === $key) {
-            $this->cacheControl = $this->parseCacheControl($values[0]);
+            $this->cacheControl = $this->parseCacheControl(implode(', ', $this->headers[$key]));
         }
     }
 

src/Symfony/Component/HttpFoundation/Tests/ResponseHeaderBagTest.php

@@ -110,6 +110,17 @@ public function testCacheControlHeader()
         $bag = new ResponseHeaderBag();
         $bag->set('Last-Modified', 'abcde');
         $this->assertEquals('private, must-revalidate', $bag->get('Cache-Control'));
+
+        $bag = new ResponseHeaderBag();
+        $bag->set('Cache-Control', array('public', 'must-revalidate'));
+        $this->assertCount(1, $bag->get('Cache-Control', null, false));
+        $this->assertEquals('must-revalidate, public', $bag->get('Cache-Control'));
+
+        $bag = new ResponseHeaderBag();
+        $bag->set('Cache-Control', 'public');
+        $bag->set('Cache-Control', 'must-revalidate', false);
+        $this->assertCount(1, $bag->get('Cache-Control', null, false));
+        $this->assertEquals('must-revalidate, public', $bag->get('Cache-Control'));
     }
 
     public function testToStringIncludesCookieHeaders()