emacs-27 acc9b46: Fix merging of region face for non-ASCII characters

[Eli Zaretskii]

branch: emacs-27
commit acc9b461538d65190cd88f87fd997f733f382ad9
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix merging of region face for non-ASCII characters
    
    * src/xdisp.c (extend_face_to_end_of_line): Restore the correct
    original face used by the iterator on this line, not the ASCII
    face.  (Bug#43363)
---
 src/xdisp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/xdisp.c b/src/xdisp.c
index 2af6144..5632aec 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -21808,13 +21808,14 @@ extend_face_to_end_of_line (struct it *it)
      in the text area has to be drawn to the end of the text area.  */
   it->glyph_row->fill_line_p = true;
 
+  const int orig_face_id = it->face_id;
   /* If current character of IT is not ASCII, make sure we have the
      ASCII face.  This will be automatically undone the next time
      get_next_display_element returns a multibyte character.  Note
      that the character will always be single byte in unibyte
      text.  */
   if (!ASCII_CHAR_P (it->c))
-      it->face_id = FACE_FOR_CHAR (f, face, 0, -1, Qnil);
+    it->face_id = FACE_FOR_CHAR (f, face, 0, -1, Qnil);
 
   /* The default face, possibly remapped. */
   struct face *default_face =
@@ -22008,6 +22009,7 @@ extend_face_to_end_of_line (struct it *it)
          if (stretch_width < 0)
            it->glyph_row->x = stretch_width;
        }
+      it->face_id = orig_face_id;
     }
   else
 #endif /* HAVE_WINDOW_SYSTEM */
@@ -22017,7 +22019,6 @@ extend_face_to_end_of_line (struct it *it)
       struct text_pos saved_pos = it->position;
       Lisp_Object saved_object = it->object;;
       enum display_element_type saved_what = it->what;
-      int saved_face_id = it->face_id;
 
       it->what = IT_CHARACTER;
       memset (&it->position, 0, sizeof it->position);
@@ -22120,7 +22121,7 @@ extend_face_to_end_of_line (struct it *it)
       it->object = saved_object;
       it->position = saved_pos;
       it->what = saved_what;
-      it->face_id = saved_face_id;
+      it->face_id = orig_face_id;
     }
 }