From 4c501365226d896183f04524966487ea8088fcc6 Mon Sep 17 00:00:00 2001
From: Jordi Boggiano <j.boggiano@seld.be>
Date: Fri, 22 Apr 2016 20:55:07 +0100
Subject: [PATCH] Avoid caching nulls, refs #5234

---
 src/Composer/Repository/Vcs/GitHubDriver.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Composer/Repository/Vcs/GitHubDriver.php b/src/Composer/Repository/Vcs/GitHubDriver.php
index 4a4e1fcea..009f1ce0b 100644
--- a/src/Composer/Repository/Vcs/GitHubDriver.php
+++ b/src/Composer/Repository/Vcs/GitHubDriver.php
@@ -188,7 +188,7 @@ class GitHubDriver extends VcsDriver
                 }
             }
 
-            if (preg_match('{[a-f0-9]{40}}i', $identifier)) {
+            if ($composer && preg_match('{[a-f0-9]{40}}i', $identifier)) {
                 $this->cache->write($identifier, json_encode($composer));
             }