Fix crash while converting empty vector to X data

* src/xselect.c (lisp_data_to_selection_data): Assume an empty
vector represents INTEGER data, instead of blindly trying to
aref it's first element.

1 files changed, 11 insertions, 1 deletions

diff --git a/src/xselect.c b/src/xselect.c
index 74d762f3055..66782d41723 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -2017,7 +2017,17 @@ lisp_data_to_selection_data (struct x_display_info *dpyinfo,
       ptrdiff_t i;
       ptrdiff_t size = ASIZE (obj);
 
-      if (SYMBOLP (AREF (obj, 0)))
+      if (!size)
+        {
+          /* This vector is empty and of unknown type.  Assume that it
+             is a vector of integers.  */
+
+          cs->data = NULL;
+          cs->format = 32;
+          cs->size = 0;
+          type = QINTEGER;
+        }
+      else if (SYMBOLP (AREF (obj, 0)))
         /* This vector is an ATOM set */
         {
           void *data;