diff -r 6ecd0980d7f9 -r 7a430116f639 mercurial/logcmdutil.py
--- a/mercurial/logcmdutil.py	Fri Jun 18 14:17:43 2021 -0700
+++ b/mercurial/logcmdutil.py	Fri Jun 18 15:48:51 2021 -0700
@@ -93,9 +93,8 @@
             },
             b"merge-diff",
         ):
-            repo.ui.pushbuffer()
-            merge.merge(ctx.p2(), wc=wctx)
-            repo.ui.popbuffer()
+            with repo.ui.silent():
+                merge.merge(ctx.p2(), wc=wctx)
         return wctx
     else:
         return ctx.p1()