--- a/mercurial/templatekw.py	Sun Feb 25 16:40:41 2018 +0900
+++ b/mercurial/templatekw.py	Sun Feb 25 14:12:34 2018 +0900
@@ -552,9 +552,8 @@
 @templatekeyword('graphwidth')
 def showgraphwidth(repo, ctx, templ, **args):
     """Integer. The width of the graph drawn by 'log --graph' or zero."""
-    # The value args['graphwidth'] will be this function, so we use an internal
-    # name to pass the value through props into this function.
-    return args.get('_graphwidth', 0)
+    # just hosts documentation; should be overridden by template mapping
+    return 0
 
 @templatekeyword('index')
 def showindex(**args):