feature #18220 Don't send default cache header for 301 redirects (e-moe)

This PR was merged into the 3.2-dev branch.

Discussion
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Don't send default cache header for 301 redirects

| Q             | A
| ------------- | ---
| Branch?       | "master"
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #17139
| License       | MIT
| Doc PR        | see comments from #17139

Commits
-------

cf253a9 17139: do not send default cache header for 301 redirects

src/Symfony/Component/HttpFoundation/RedirectResponse.php

@@ -41,6 +41,10 @@ public function __construct($url, $status = 302, $headers = array())
         if (!$this->isRedirect()) {
             throw new \InvalidArgumentException(sprintf('The HTTP status code is not a redirect ("%s" given).', $status));
         }
+
+        if (301 == $status && !array_key_exists('cache-control', $headers)) {
+            $this->headers->remove('cache-control');
+        }
     }
 
     /**

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

@@ -80,4 +80,17 @@ public function testCreate()
         $this->assertInstanceOf('Symfony\Component\HttpFoundation\RedirectResponse', $response);
         $this->assertEquals(301, $response->getStatusCode());
     }
+
+    public function testCacheHeaders()
+    {
+        $response = new RedirectResponse('foo.bar', 301);
+        $this->assertFalse($response->headers->hasCacheControlDirective('no-cache'));
+
+        $response = new RedirectResponse('foo.bar', 301, array('cache-control' => 'max-age=86400'));
+        $this->assertFalse($response->headers->hasCacheControlDirective('no-cache'));
+        $this->assertTrue($response->headers->hasCacheControlDirective('max-age'));
+
+        $response = new RedirectResponse('foo.bar', 302);
+        $this->assertTrue($response->headers->hasCacheControlDirective('no-cache'));
+    }
 }