diff -r 7775c1fb8fa0 -r 52e6171ec822 mercurial/obsutil.py
--- a/mercurial/obsutil.py	Tue May 29 18:13:19 2018 +0200
+++ b/mercurial/obsutil.py	Sat Aug 25 15:19:43 2018 +0900
@@ -465,7 +465,7 @@
     succsmarkers = repo.obsstore.successors.get
     public = phases.public
     addedmarkers = tr.changes.get('obsmarkers')
-    addedrevs = tr.changes.get('revs')
+    addedrevs = tr.changes['revs']
     seenrevs = set()
     obsoleted = set()
     for mark in addedmarkers: