patch 8.2.4106: going over the end of the w_lines arrayv8.2.4106

Problem:    Going over the end of the w_lines array.
Solution:   Break out of the loop when "idx" is too big. (issue #9540)

1 files changed, 5 insertions, 0 deletions

diff --git a/src/drawscreen.c b/src/drawscreen.c
index 453ca91c33..e0fb122995 100644
--- a/src/drawscreen.c
+++ b/src/drawscreen.c
@@ -2539,6 +2539,11 @@ win_update(win_T *wp)
 	    eof = TRUE;
 	    break;
 	}
+
+	// Safety check: if any of the wl_size values is wrong we might go over
+	// the end of w_lines[].
+	if (idx >= Rows)
+	    break;
     }
 
     // End of loop over all window lines.