From 2ebbf211e7514fe49c20530f1ee171ae08562c9c Mon Sep 17 00:00:00 2001
From: Christian Selig <me@christianselig.com>
Date: Thu, 22 Aug 2013 19:00:20 +0000
Subject: [PATCH] Added additional condition to prevent variable from being
 accessed when it hasn't been set.

---
 theme/theme.inc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/theme/theme.inc b/theme/theme.inc
index 92878555..895ec8fe 100644
--- a/theme/theme.inc
+++ b/theme/theme.inc
@@ -361,6 +361,9 @@ function theme_islandora_datastream_revert_link(array $vars) {
     }
     $link = "islandora/object/{$datastream->parent->id}/datastream/{$datastream->id}/version/{$vars['version']}/revert";
   }
+  else {
+    $can_revert = FALSE;
+  }
 
   if ($can_revert) {
     return l(t('revert'), $link);