[Emacs-diffs] emacs-26 9dde8be: Fix redisplay of overlay-arrows on GUI frames

[Eli Zaretskii]

branch: emacs-26
commit 9dde8be9cd8dc9defdae282ed24eaf2dd6bf4c31
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix redisplay of overlay-arrows on GUI frames
    
    * src/xdisp.c (try_window_reusing_current_matrix)
    (try_cursor_movement): Disallow these optimizations if the buffer
    has overlay arrow(s) shown on the fringe(s).  (Bug#29198)
---
 src/xdisp.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/xdisp.c b/src/xdisp.c
index 69b74dc..5fdd39b 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -16066,8 +16066,10 @@ try_cursor_movement (Lisp_Object window, struct 
text_pos startp,
         since the handling of this_line_start_pos, etc., in redisplay
         handles the same cases.  */
       && !EQ (window, minibuf_window)
-      && (FRAME_WINDOW_P (f)
-         || !overlay_arrow_in_current_buffer_p ()))
+      /* When overlay arrow is shown in current buffer, point movement
+        is no longer "simple", as it typically causes the overlay
+        arrow to move as well.  */
+      && !overlay_arrow_in_current_buffer_p ())
     {
       int this_scroll_margin, top_scroll_margin;
       struct glyph_row *row = NULL;
@@ -17698,7 +17700,11 @@ try_window_reusing_current_matrix (struct window *w)
       /* Don't try to reuse the display if windows have been split
         or such.  */
       || windows_or_buffers_changed
-      || f->cursor_type_changed)
+      || f->cursor_type_changed
+      /* This function cannot handle buffers where the overlay arrow
+        is shown on the fringes, because if the arrow position
+        changes, we cannot just reuse the current matrix.  */
+      || overlay_arrow_in_current_buffer_p ())
     return false;
 
   /* Can't do this if showing trailing whitespace.  */