From d16e51e8d289400f6724ed9a568da7fb2237a472 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Mon, 20 Sep 2021 15:22:07 +0300
Subject: [PATCH] Fix assertion violation with zero-width :box attributes

* src/xfaces.c (merge_face_ref): Don't allow :box attribute with a
zero value.  (Bug#50699)
---
 src/xfaces.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/xfaces.c b/src/xfaces.c
index aefed54ebcb..c5b7a568aeb 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -2709,7 +2709,7 @@ merge_face_ref (struct window *w,
 		{
 		  if (EQ (value, Qt))
 		    value = make_fixnum (1);
-		  if (FIXNUMP (value)
+		  if ((FIXNUMP (value) && XFIXNUM (value) != 0)
 		      || STRINGP (value)
 		      || CONSP (value)
 		      || NILP (value))
-- 
2.39.5