vim-patch:8.1.0125: virtual edit replace with multi-byte fails at end of line

Problem:    Virtual edit replace with multi-byte fails at end of line. (Lukas
            Werling)
Solution:   use ins_char() to add the character. (Christian Brabandt,
            closes vim/vim#3114)  Rename PCHAR() to PBYTE() to avoid mistakes like
            this.
https://github.com/vim/vim/commit/630afe889a2a02b367ea8eaaa48e66ed81e77ff3

2 files changed, 40 insertions, 11 deletions

diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 2a3b7beb8e..ef440a27a2 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -1638,12 +1638,25 @@ static void mb_adjust_opend(oparg_T *oap)
 /*
  * Put character 'c' at position 'lp'
  */
-static inline void pchar(pos_T lp, int c)
+static inline void pbyte(pos_T lp, int c)
 {
     assert(c <= UCHAR_MAX);
     *(ml_get_buf(curbuf, lp.lnum, true) + lp.col) = (char_u)c;
 }
 
+// Replace the character under the cursor with "c".
+// This takes care of multi-byte characters.
+static void replace_character(int c)
+{
+  const int n = State;
+
+  State = REPLACE;
+  ins_char(c);
+  State = n;
+  // Backup to the replaced character.
+  dec_cursor();
+}
+
 /*
  * Replace a whole area with one character.
  */
@@ -1795,12 +1808,7 @@ int op_replace(oparg_T *oap, int c)
            * with a multi-byte and the other way around. */
           if (curwin->w_cursor.lnum == oap->end.lnum)
             oap->end.col += (*mb_char2len)(c) - (*mb_char2len)(n);
-          n = State;
-          State = REPLACE;
-          ins_char(c);
-          State = n;
-          /* Backup to the replaced character. */
-          dec_cursor();
+          replace_character(c);
         } else {
           if (n == TAB) {
             int end_vcol = 0;
@@ -1815,7 +1823,7 @@ int op_replace(oparg_T *oap, int c)
             if (curwin->w_cursor.lnum == oap->end.lnum)
               getvpos(&oap->end, end_vcol);
           }
-          pchar(curwin->w_cursor, c);
+          pbyte(curwin->w_cursor, c);
         }
       } else if (virtual_op && curwin->w_cursor.lnum == oap->end.lnum) {
         int virtcols = oap->end.coladd;
@@ -1830,9 +1838,14 @@ int op_replace(oparg_T *oap, int c)
         coladvance_force(getviscol2(oap->end.col, oap->end.coladd) + 1);
         curwin->w_cursor.col -= (virtcols + 1);
         for (; virtcols >= 0; virtcols--) {
-          pchar(curwin->w_cursor, c);
-          if (inc(&curwin->w_cursor) == -1)
+          if (utf_char2len(c) > 1) {
+            replace_character(c);
+          } else {
+            pbyte(curwin->w_cursor, c);
+          }
+          if (inc(&curwin->w_cursor) == -1) {
             break;
+          }
         }
       }
 
@@ -2007,7 +2020,7 @@ int swapchar(int op_type, pos_T *pos)
       ins_char(nc);
       curwin->w_cursor = sp;
     } else
-      pchar(*pos, nc);
+      pbyte(*pos, nc);
     return TRUE;
   }
   return FALSE;
diff --git a/src/nvim/testdir/test_virtualedit.vim b/src/nvim/testdir/test_virtualedit.vim
index d49025237b..abe79f6a4a 100644
--- a/src/nvim/testdir/test_virtualedit.vim
+++ b/src/nvim/testdir/test_virtualedit.vim
@@ -42,6 +42,22 @@ func Test_paste_end_of_line()
   set virtualedit=
 endfunc
 
+func Test_replace_end_of_line()
+  new
+  set virtualedit=all
+  call setline(1, range(20))
+  exe "normal! gg2jv10lr-"
+  call assert_equal(["1", "-----------", "3"], getline(2,4))
+  if has('multi_byte')
+    call setline(1, range(20))
+    exe "normal! gg2jv10lr\<c-k>hh"
+    call assert_equal(["1", "───────────", "3"], getline(2,4))
+  endif
+
+  bwipe!
+  set virtualedit=
+endfunc
+
 func Test_edit_CTRL_G()
   new
   set virtualedit=insert