--- a/mercurial/bookmarks.py	Wed Apr 04 10:13:08 2018 -0700
+++ b/mercurial/bookmarks.py	Wed Apr 04 15:13:32 2018 -0700
@@ -349,8 +349,8 @@
     return heads
 
 def calculateupdate(ui, repo, checkout):
-    '''Return a tuple (targetrev, movemarkfrom) indicating the rev to
-    check out and where to move the active bookmark from, if needed.'''
+    '''Return a tuple (activemark, movemarkfrom) indicating the active bookmark
+    and where to move the active bookmark from, if needed.'''
     movemarkfrom = None
     if checkout is None:
         activemark = repo._activebookmark