diff -r 6d642ecf1a89 -r e46533c3201e mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Mon Feb 13 20:47:41 2017 -0800
+++ b/mercurial/debugcommands.py	Wed Feb 01 17:39:31 2017 +0100
@@ -1036,6 +1036,11 @@
     flags = repo.known([bin(s) for s in ids])
     ui.write("%s\n" % ("".join([f and "1" or "0" for f in flags])))
 
+@command('debuglabelcomplete', [], _('LABEL...'))
+def debuglabelcomplete(ui, repo, *args):
+    '''backwards compatibility with old bash completion scripts (DEPRECATED)'''
+    commands.debugnamecomplete(ui, repo, *args)
+
 @command('debugupgraderepo', [
     ('o', 'optimize', [], _('extra optimization to perform'), _('NAME')),
     ('', 'run', False, _('performs an upgrade')),