diff --git a/kallithea/lib/vcs/backends/hg/repository.py b/kallithea/lib/vcs/backends/hg/repository.py
--- a/kallithea/lib/vcs/backends/hg/repository.py
+++ b/kallithea/lib/vcs/backends/hg/repository.py
@@ -421,12 +421,12 @@ class MercurialRepository(BaseRepository
 
         try:
             revision = hex(self._repo.lookup(revision))
+        except (IndexError, ValueError, RepoLookupError, TypeError):
+            msg = ("Revision %s does not exist for %s" % (revision, self))
+            raise ChangesetDoesNotExistError(msg)
         except (LookupError, ):
             msg = ("Ambiguous identifier `%s` for %s" % (revision, self))
             raise ChangesetDoesNotExistError(msg)
-        except (IndexError, ValueError, RepoLookupError, TypeError):
-            msg = ("Revision %s does not exist for %s" % (revision, self))
-            raise ChangesetDoesNotExistError(msg)
 
         return revision