feat(api): relax statusline fillchar width check

Treat fillchar as single-width even if it isn't.

1 files changed, 5 insertions, 4 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index c37df45c14..1a324bfaa5 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -2241,7 +2241,7 @@ Array nvim_get_mark(String name, Dictionary opts, Error *err)
 ///           - winid: (number) |window-ID| of the window to use as context for statusline.
 ///           - maxwidth: (number) Maximum width of statusline.
 ///           - fillchar: (string) Character to fill blank spaces in the statusline (see
-///                                'fillchars').
+///                                'fillchars'). Treated as single-width even if it isn't.
 ///           - highlights: (boolean) Return highlight information.
 ///           - use_tabline: (boolean) Evaluate tabline instead of statusline. When |TRUE|, {winid}
 ///                                    is ignored.
@@ -2277,11 +2277,12 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
 
   if (HAS_KEY(opts->fillchar)) {
     if (opts->fillchar.type != kObjectTypeString || opts->fillchar.data.string.size == 0
-        || char2cells(fillchar = utf_ptr2char((char_u *)opts->fillchar.data.string.data)) != 1
-        || (size_t)utf_char2len(fillchar) != opts->fillchar.data.string.size) {
-      api_set_error(err, kErrorTypeValidation, "fillchar must be a single-width character");
+        || ((size_t)utf_ptr2len((char_u *)opts->fillchar.data.string.data)
+            != opts->fillchar.data.string.size)) {
+      api_set_error(err, kErrorTypeValidation, "fillchar must be a single character");
       return result;
     }
+    fillchar = utf_ptr2char((char_u *)opts->fillchar.data.string.data);
   }
 
   if (HAS_KEY(opts->highlights)) {