diff -r b7a75b9a3386 -r 0407a51b9d8c mercurial/obsolete.py
--- a/mercurial/obsolete.py	Tue Jul 11 08:52:55 2017 -0700
+++ b/mercurial/obsolete.py	Fri Jul 14 14:22:40 2017 -0700
@@ -991,8 +991,7 @@
     if 'user' not in metadata:
         metadata['user'] = repo.ui.username()
     useoperation = repo.ui.configbool('experimental',
-                                      'evolution.track-operation',
-                                      False)
+        'evolution.track-operation')
     if useoperation and operation:
         metadata['operation'] = operation
     tr = repo.transaction('add-obsolescence-marker')