From 25fb3f9b467c5dccddca4afead9b1ea6e29b08fb Mon Sep 17 00:00:00 2001
From: Pip Cet <pipcet@protonmail.com>
Date: Tue, 26 May 2026 14:07:11 +0000
Subject: [PATCH] Fix self-insert-command in multibyte buffers (bug#81129)

* src/cmds.c (internal_self_insert): Pass PT_BYTE to FETCH_BYTE, not
PT.
---
 src/cmds.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cmds.c b/src/cmds.c
index 9ca9a6d28de..f226c7542b3 100644
--- a/src/cmds.c
+++ b/src/cmds.c
@@ -489,7 +489,7 @@ internal_self_insert (int c, EMACS_INT n)
 	SET_PT_BOTH (PT - 1, PT_BYTE - 1);
       auto_fill_result = call0 (Qinternal_auto_fill);
       /* Test PT < ZV in case the auto-fill-function is strange.  */
-      if (c == '\n' && PT < ZV && FETCH_BYTE (PT) == '\n')
+      if (c == '\n' && PT < ZV && FETCH_BYTE (PT_BYTE) == '\n')
 	SET_PT_BOTH (PT + 1, PT_BYTE + 1);
       if (!NILP (auto_fill_result))
 	hairy = 2;