diff --git a/reviewboard/diffviewer/models.py b/reviewboard/diffviewer/models.py
index 33581a6f2b784bfa0c137ecb65744a48fd4c4a2b..de046fd694700c420082bc150ffd084615562c4c 100644
--- a/reviewboard/diffviewer/models.py
+++ b/reviewboard/diffviewer/models.py
@@ -239,9 +239,10 @@ class FileDiff(models.Model):
             return None
 
     def _set_parent_diff(self, parent_diff):
-        if not parent_diff:
-            return False
 
+        if parent_diff != b'':
+            hashkey = self._hash_hexdigest(parent_diff)
+            
         # Add hash to table if it doesn't exist, and set diff_hash to this.
         self.parent_diff_hash, is_new = \
             RawFileDiffData.objects.get_or_create_from_data(parent_diff)