diff -r ee3872c14ab3 -r 7b14d649af1b mercurial/branchmap.py
--- a/mercurial/branchmap.py	Tue Nov 19 23:19:57 2019 +0900
+++ b/mercurial/branchmap.py	Tue Nov 19 23:49:05 2019 +0900
@@ -27,7 +27,7 @@
     stringutil,
 )
 
-if not globals():
+if pycompat.TYPE_CHECKING:
     from typing import (
         Any,
         Callable,