bug #26886 Don't assume that file binary exists on *nix OS (teohhanhui)

fabpot · fabpot · commit b0410d457ed0 · 2018-04-17T12:07:04.000+02:00
This PR was merged into the 2.7 branch. Discussion ---------- Don't assume that file binary exists on *nix OS | Q | A | ------------- | --- | Branch? | 2.7 | Bug fix? | yes | New feature? | no | BC breaks? | no | Deprecations? | no | Tests pass? | yes | Fixed tickets | N/A | License | MIT | Doc PR | N/A Certain lightweight distributions such as Alpine Linux (popular for smaller Docker images) do not include it by default. Commits ------- e2c1f24 Don't assume that file binary exists on *nix OS
diff --git a/src/Symfony/Component/HttpFoundation/File/MimeType/FileBinaryMimeTypeGuesser.php b/src/Symfony/Component/HttpFoundation/File/MimeType/FileBinaryMimeTypeGuesser.php
@@ -43,7 +43,21 @@ public function __construct($cmd = 'file -b --mime %s 2>/dev/null')
      */
     public static function isSupported()
     {
-        return '\\' !== DIRECTORY_SEPARATOR && function_exists('passthru') && function_exists('escapeshellarg');
+        static $supported = null;
+
+        if (null !== $supported) {
+            return $supported;
+        }
+
+        if ('\\' === DIRECTORY_SEPARATOR || !function_exists('passthru') || !function_exists('escapeshellarg')) {
+            return $supported = false;
+        }
+
+        ob_start();
+        passthru('command -v file', $exitStatus);
+        $binPath = trim(ob_get_clean());
+
+        return $supported = 0 === $exitStatus && '' !== $binPath;
     }
 
     /**
