diff -r 6fef387af1da -r 77ef3498ceb3 mercurial/logcmdutil.py
--- a/mercurial/logcmdutil.py	Tue Mar 19 23:00:07 2019 -0700
+++ b/mercurial/logcmdutil.py	Sun Mar 10 12:57:24 2019 +0900
@@ -542,7 +542,7 @@
     regular display via changesetprinter() is done.
     """
     postargs = (differ, opts, buffered)
-    if opts.get('template') == 'json':
+    if opts.get('template') in {'cbor', 'json'}:
         fm = ui.formatter('log', opts)
         return changesetformatter(ui, repo, fm, *postargs)