master ed4ba79ea8: Avoid infloop in redisplay when displaying a tooltip

[Eli Zaretskii]

branch: master
commit ed4ba79ea8f2be2d01f6447910e2c8319908d0d6
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Avoid infloop in redisplay when displaying a tooltip
    
    * src/xdisp.c (try_window): Ensure we fail if 'display_line'
    indicates that the dimensions of the glyph matrix are
    insufficient.  (Bug#56561)
---
 src/xdisp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/xdisp.c b/src/xdisp.c
index f205327cc3..1940d16a01 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -20200,9 +20200,16 @@ try_window (Lisp_Object window, struct text_pos pos, 
int flags)
   /* Display all lines of W.  */
   while (it.current_y < it.last_visible_y)
     {
+      int last_row_scale = it.w->nrows_scale_factor;
+      int last_col_scale = it.w->ncols_scale_factor;
       if (display_line (&it, cursor_vpos))
        last_text_row = it.glyph_row - 1;
-      if (f->fonts_changed && !(flags & TRY_WINDOW_IGNORE_FONTS_CHANGE))
+      if (f->fonts_changed
+         && !((flags & TRY_WINDOW_IGNORE_FONTS_CHANGE)
+              /* If the matrix dimensions are insufficient, we _must_
+                 fail and let dispnew.c reallocate the matrix.  */
+              && last_row_scale == it.w->nrows_scale_factor
+              && last_col_scale == it.w->ncols_scale_factor))
        return 0;
     }