vim-patch:9.2.0645: Composing chars no longer accepted in end-id abbr

Problem:  Composing chars are no longer accepted in end-id abbreviation
          (after 9.2.0629).
Solution: Unescape all chars using vim_unescape_csi() instead of using
          mb_unescape() on individual chars, so that mb_ptr2len() and
          MB_PTR_ADV() can still be used.

closes: vim/vim#20514

https://github.com/vim/vim/commit/23a84d28a8c4acfda1d01bde2b5366a496431d88

2 files changed, 15 insertions, 15 deletions

diff --git a/src/nvim/keycodes.c b/src/nvim/keycodes.c
index ef067f68e2..9827604d67 100644
--- a/src/nvim/keycodes.c
+++ b/src/nvim/keycodes.c
@@ -850,7 +850,8 @@ char *vim_strsave_escape_ks(char *p)
 
 /// Remove escaping from K_SPECIAL characters.  Reverse of
 /// vim_strsave_escape_ks().  Works in-place.
-void vim_unescape_ks(char *p)
+/// Returns the number of bytes in the unescaped string.
+size_t vim_unescape_ks(char *p)
 {
   uint8_t *s = (uint8_t *)p;
   uint8_t *d = (uint8_t *)p;
@@ -864,4 +865,5 @@ void vim_unescape_ks(char *p)
     }
   }
   *d = NUL;
+  return (size_t)((char *)d - p);
 }
diff --git a/src/nvim/mapping.c b/src/nvim/mapping.c
index a922d42b1f..3bebbb62eb 100644
--- a/src/nvim/mapping.c
+++ b/src/nvim/mapping.c
@@ -628,29 +628,28 @@ static int buf_do_map(int maptype, MapArguments *args, int mode, bool is_abbrev,
         // vi-compatible way.
         int same = -1;
 
-        const char *p = lhs;
-        const char *p_char = mb_unescape(&p);
-        if (p_char == NULL) {
-          p_char = p++;
-        }
-        const int first = vim_iswordp(p_char);
+        char keys_unescaped[MAXMAPLEN + 1];
+        xmemcpyz(keys_unescaped, lhs, (size_t)len);
+        size_t keys_unescaped_len = vim_unescape_ks(keys_unescaped);
+        const char *p = keys_unescaped;
+
+        const int first = vim_iswordp(p);
         int last = first;
+        MB_PTR_ADV(p);
         int n = 1;
-        while (p < lhs + len) {
+        while (p < keys_unescaped + keys_unescaped_len) {
           n++;                                  // nr of (multi-byte) chars
-          p_char = mb_unescape(&p);
-          if (p_char == NULL) {
-            p_char = p++;
-          }
-          last = vim_iswordp(p_char);           // type of last char
+          last = vim_iswordp(p);                // type of last char
           if (same == -1 && last != first) {
             same = n - 1;                       // count of same char type
           }
+          MB_PTR_ADV(p);
         }
         if (last && n > 2 && same >= 0 && same < n - 1) {
           retval = 1;
           goto theend;
         }
+
         // An abbreviation cannot contain white space.
         for (n = 0; n < len; n++) {
           if (ascii_iswhite(lhs[n])) {
@@ -1537,8 +1536,7 @@ bool check_abbr(int c, char *ptr, int col, int mincol)
       if (strchr(mp->m_keys, K_SPECIAL) != NULL) {
         // Might have K_SPECIAL escaped mp->m_keys.
         q = xstrdup(mp->m_keys);
-        vim_unescape_ks(q);
-        qlen = (int)strlen(q);
+        qlen = (int)vim_unescape_ks(q);
       }
       // find entries with right mode and keys
       int match = (mp->m_mode & State)