diff --git a/mercurial/exchange.py b/mercurial/exchange.py
--- a/mercurial/exchange.py
+++ b/mercurial/exchange.py
@@ -658,7 +658,7 @@ def _pushdiscoverybookmarks(pushop):
     ui.debug("checking for updated bookmarks\n")
     ancestors = ()
     if pushop.revs:
-        revnums = map(repo.changelog.rev, pushop.revs)
+        revnums = pycompat.maplist(repo.changelog.rev, pushop.revs)
         ancestors = repo.changelog.ancestors(revnums, inclusive=True)
 
     remotebookmark = listkeys(remote, 'bookmarks')