Fix error when calling DND movement tracking function

* src/xterm.c (x_dnd_begin_drag_and_drop): Verify
x_dnd_movement_x and x_dnd_movement_y are wholenums before
caling posn-at-x-y.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/xterm.c b/src/xterm.c
index f5770ad7e7c..57a64cb5d12 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -9540,7 +9540,12 @@ x_dnd_begin_drag_and_drop (struct frame *f, Time time, Atom xaction,
           x_dnd_movement_frame = NULL;
 
           if (!NILP (Vx_dnd_movement_function)
-              && !FRAME_TOOLTIP_P (XFRAME (frame_object)))
+              && !FRAME_TOOLTIP_P (XFRAME (frame_object))
+              && x_dnd_movement_x >= 0
+              && x_dnd_movement_y >= 0
+              && x_dnd_frame
+              && (XFRAME (frame_object) != x_dnd_frame
+                  || x_dnd_allow_current_frame))
             {
               x_dnd_old_window_attrs = root_window_attrs;
               x_dnd_unwind_flag = true;