[HttpFoundation] fix guessing mime-types of files with leading dash

src/Symfony/Component/HttpFoundation/File/MimeType/FileBinaryMimeTypeGuesser.php

@@ -31,7 +31,7 @@ class FileBinaryMimeTypeGuesser implements MimeTypeGuesserInterface
      *
      * @param string $cmd The command to run to get the mime type of a file
      */
-    public function __construct($cmd = 'file -b --mime %s 2>/dev/null')
+    public function __construct($cmd = 'file -b --mime -- %s 2>/dev/null')
     {
         $this->cmd = $cmd;
     }
@@ -80,7 +80,7 @@ class FileBinaryMimeTypeGuesser implements MimeTypeGuesserInterface
         ob_start();
 
         // need to use --mime instead of -i. see #6641
-        passthru(sprintf($this->cmd, escapeshellarg($path)), $return);
+        passthru(sprintf($this->cmd, escapeshellarg((0 === strpos($path, '-') ? './' : '').$path)), $return);
         if ($return > 0) {
             ob_end_clean();
 

src/Symfony/Component/HttpFoundation/Tests/File/MimeType/MimeTypeTest.php

@@ -20,7 +20,16 @@ use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser;
  */
 class MimeTypeTest extends TestCase
 {
-    protected $path;
+    public function testGuessWithLeadingDash()
+    {
+        $cwd = getcwd();
+        chdir(__DIR__.'/../Fixtures');
+        try {
+            $this->assertEquals('image/gif', MimeTypeGuesser::getInstance()->guess('-test'));
+        } finally {
+            chdir($cwd);
+        }
+    }
 
     public function testGuessImageWithoutExtension()
     {