diff --git a/swh/indexer/origin_head.py b/swh/indexer/origin_head.py
--- a/swh/indexer/origin_head.py
+++ b/swh/indexer/origin_head.py
@@ -30,6 +30,8 @@
     def index(self, origin):
         origin_id = origin['id']
         latest_snapshot = self.storage.snapshot_get_latest(origin_id)
+        if latest_snapshot is None:
+            return None
         method = getattr(self, '_try_get_%s_head' % origin['type'], None)
         if method is None:
             method = self._try_get_head_generic
@@ -111,8 +113,7 @@
     def _try_get_head_generic(self, snapshot):
         # Works on 'deposit', 'svn', and 'pypi'.
         try:
-            if isinstance(snapshot, dict):
-                branches = snapshot['branches']
+            branches = snapshot['branches']
         except KeyError:
             return None
         else: