From 3fc36f427a6dfe5366fd1391fee1d037a1bd6cd7 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 27 May 2017 15:57:38 +0300
Subject: [PATCH] Avoid args-out-of-range errors on fringe clicks after "C-h k"

* src/keyboard.c (echo_truncate): Don't call Ftruncate if the echo
message is already shorter than NCHARS.  (Bug#27040)
---
 src/keyboard.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/keyboard.c b/src/keyboard.c
index c9fa2a9f5e1..55486c6d9ab 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -634,7 +634,8 @@ echo_length (void)
 static void
 echo_truncate (ptrdiff_t nchars)
 {
-  if (STRINGP (KVAR (current_kboard, echo_string)))
+  Lisp_Object es = KVAR (current_kboard, echo_string);
+  if (STRINGP (es) && SCHARS (es) > nchars)
     kset_echo_string (current_kboard,
 		      Fsubstring (KVAR (current_kboard, echo_string),
 				  make_number (0), make_number (nchars)));
-- 
2.39.2