diff -r b4c193509cd0 -r 96fcc37a9c80 mercurial/configitems.py
--- a/mercurial/configitems.py	Thu Oct 22 22:29:22 2020 -0700
+++ b/mercurial/configitems.py	Thu Oct 22 23:10:06 2020 -0700
@@ -251,6 +251,15 @@
     default=None,
     alias=[(b'ui', b'pre-merge-tool-output-template')],
 )
+coreconfigitem(
+    b'command-templates', b'oneline-summary', default=None,
+)
+coreconfigitem(
+    b'command-templates',
+    b'oneline-summary.*',
+    default=dynamicdefault,
+    generic=True,
+)
 _registerdiffopts(section=b'commands', configprefix=b'commit.interactive.')
 coreconfigitem(
     b'commands', b'commit.post-status', default=False,