--- a/mercurial/error.py	Mon May 08 22:14:56 2017 +0900
+++ b/mercurial/error.py	Sun May 14 15:41:27 2017 +0900
@@ -174,7 +174,7 @@
 class PushRaced(RuntimeError):
     """An exception raised during unbundling that indicate a push race"""
 
-class ProgrammingError(RuntimeError):
+class ProgrammingError(Hint, RuntimeError):
     """Raised if a mercurial (core or extension) developer made a mistake"""
 
 # bundle2 related errors