From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Sun, 20 Sep 2020 21:32:45 +0000 (+0200)
Subject: Make xterm-mouse-event check whether the click event is valid
X-Git-Tag: emacs-28.0.90~5977
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=6d9297abe0561e9a3750d4f07919b2973ec31504;p=emacs.git

Make xterm-mouse-event check whether the click event is valid

* lisp/xt-mouse.el (xterm-mouse-event): Defensively check against
a situation that shouldn't happen (but does) (bug#17378).
---

diff --git a/lisp/xt-mouse.el b/lisp/xt-mouse.el
index 2b9fab556e0..362d29b943d 100644
--- a/lisp/xt-mouse.el
+++ b/lisp/xt-mouse.el
@@ -237,7 +237,10 @@ which is the \"1006\" extension implemented in Xterm >= 277."
 		      (xterm-mouse--read-event-sequence extension))
 		     (t
 		      (error "Unsupported XTerm mouse protocol")))))
-    (when click
+    (when (and click
+               ;; In very obscure circumstances, the click may become
+               ;; invalid (see bug#17378).
+               (>= (nth 1 click) 0))
       (let* ((type (nth 0 click))
              (x    (nth 1 click))
              (y    (nth 2 click))