diff -r 1aa4d646d0de -r 77c9ee77687c mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Fri Apr 13 11:21:55 2018 -0700
+++ b/mercurial/debugcommands.py	Wed Apr 11 18:15:51 2018 -0700
@@ -2912,7 +2912,7 @@
         if opts['peer'] == 'http2':
             ui.write(_('creating http peer for wire protocol version 2\n'))
             peer = httppeer.httpv2peer(
-                ui, path, 'api/%s' % wireprototypes.HTTPV2,
+                ui, path, 'api/%s' % wireprototypes.HTTP_WIREPROTO_V2,
                 opener, httppeer.urlreq.request, {})
         elif opts['peer'] == 'raw':
             ui.write(_('using raw connection to peer\n'))