[Mlterm-dev-en] [PATCH] crash on the '\e[21t' (report window title) control sequence

[R <0xe...@gm...>]

If the window name wasn't already set with '\e]2;TITLE\a', writing a
'\e[21t' inside a mlterm window will cause a segmentation fault in
vtemu/vt_parser.c:report_window_or_icon_name() when it tries to
dereference the title variable set from vt_parser->win_name. (And it's
probably the same problem with vt_parser->icon_name).

The following patch will cause it to return an empty string in that case:

diff -r a2f8558d621e vtemu/vt_parser.c
--- a/vtemu/vt_parser.c Sun Nov 18 22:36:25 2018 +0900
+++ b/vtemu/vt_parser.c Tue Nov 20 06:07:41 2018 +0200
@@ -1666,6 +1666,9 @@
     title = vt_parser->icon_name;
     pre = "\x1b]L";
   }
+  if (!title) {
+    title = "";
+  }

   /* see parse_title() */
   src_encoding = vt_get_char_encoding("auto");