commit https://github.com/vim/vim/commit/502ae4ba63561c98ac69af26cd9883bfd18d225f Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jul 16 19:50:13 2016 +0200 patch 7.4.2051 Problem: No proper testing of trunc_string(). Solution: Add a unittest for message.c.

--- a/src/message.c
+++ b/src/message.c
@@ -260,7 +260,7 @@ trunc_string(
 	    return;
 	}
 	n = ptr2cells(s + e);
-	if (len + n >= half)
+	if (len + n > half)
 	    break;
 	len += n;
 	buf[e] = s[e];