From 64a50d08c4866011be73d6af0e8ae90e06c3f949 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sat, 13 Jan 2024 08:29:54 +0800
Subject: [PATCH] vim-patch:9.1.0021: i_CTRL-R- doesn't work for multibyte
 chars in Replace mode

Problem:  i_CTRL-R- doesn't work for multibyte chars in Replace mode,
          Coverity complains missing return value for u_save_cursor()
Solution: Use mb_charlen() and del_chars() instead, handle failure mode
          for u_save_cursor() correctly (@zeertzjq)

closes: vim/vim#13846

https://github.com/vim/vim/commit/424ec1f235a53131042aed94d30f6e2528e551d9
---
 src/nvim/ops.c                      |  5 ++++-
 test/old/testdir/test_registers.vim | 16 ++++++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 32095177be..84cba5d05c 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -1286,7 +1286,10 @@ int insert_reg(int regname, bool literally_arg)
           if ((State & REPLACE_FLAG) != 0) {
             pos_T curpos;
             u_save_cursor();
-            del_bytes((colnr_T)strlen(reg->y_array[0]), true, false);
+            if (u_save_cursor() == FAIL) {
+              return FAIL;
+            }
+            del_chars(mb_charlen(reg->y_array[0]), true);
             curpos = curwin->w_cursor;
             if (oneright() == FAIL) {
               // hit end of line, need to put forward (after the current position)
diff --git a/test/old/testdir/test_registers.vim b/test/old/testdir/test_registers.vim
index 7cc5ebbe6f..bc90de806f 100644
--- a/test/old/testdir/test_registers.vim
+++ b/test/old/testdir/test_registers.vim
@@ -893,7 +893,7 @@ endfunc
 func Test_insert_small_delete_replace_mode()
   new
   call setline(1, ['foo', 'bar', 'foobar',  'bar'])
-  let @-='foo'
+  let @- = 'foo'
   call cursor(2, 1)
   exe ":norm! R\<C-R>-\<C-R>-"
   call assert_equal('foofoo', getline(2))
@@ -904,9 +904,21 @@ func Test_insert_small_delete_replace_mode()
   exe ":norm! R\<C-R>-ZZZZ"
   call assert_equal(['foo', 'foofoo', '',  'bfoobarZZZZ'], getline(1, 4))
   call cursor(1, 1)
-  let @-=''
+  let @- = ''
   exe ":norm! R\<C-R>-ZZZ"
   call assert_equal(['ZZZ', 'foofoo', '',  'bfoobarZZZZ'], getline(1, 4))
+  let @- = 'βbβ'
+  call cursor(4, 1)
+  exe ":norm! R\<C-R>-"
+  call assert_equal(['ZZZ', 'foofoo', '',  'βbβobarZZZZ'], getline(1, 4))
+  let @- = 'bβb'
+  call cursor(4, 1)
+  exe ":norm! R\<C-R>-"
+  call assert_equal(['ZZZ', 'foofoo', '',  'bβbobarZZZZ'], getline(1, 4))
+  let @- = 'βbβ'
+  call cursor(4, 1)
+  exe ":norm! R\<C-R>-"
+  call assert_equal(['ZZZ', 'foofoo', '',  'βbβobarZZZZ'], getline(1, 4))
   bwipe!
 endfunc