--- a/mercurial/debugcommands.py	Sat Dec 09 19:42:51 2017 -0600
+++ b/mercurial/debugcommands.py	Sun Dec 10 19:39:39 2017 +0900
@@ -888,8 +888,8 @@
     if ui.verbose:
         fm.plain(' config default')
     fm.plain('\n')
-    fm.startitem()
     for fv in upgrade.allformatvariant:
+        fm.startitem()
         repovalue = fv.fromrepo(repo)
         configvalue = fv.fromconfig(repo)
 
@@ -916,6 +916,7 @@
         fm.condwrite(ui.verbose, 'default', ' %7s', formatvalue(fv.default),
                      label='formatvariant.default')
         fm.plain('\n')
+    fm.end()
 
 @command('debugfsinfo', [], _('[PATH]'), norepo=True)
 def debugfsinfo(ui, path="."):