[gtk/wip/otte/for-master: 6/9] notebook: Don't crash on drags not coming from a notebook

[Benjamin Otte <otte src gnome org>]

commit 4e88d5a7cf0be3e1fae2a1e6076a4325014647ee
Author: Benjamin Otte <otte redhat com>
Date:   Thu Mar 5 06:58:12 2020 +0100

    notebook: Don't crash on drags not coming from a notebook

 gtk/gtknotebook.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index 92f7651a2e..d20342b1f2 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -3359,7 +3359,7 @@ gtk_notebook_drag_drop (GtkDropTarget *dest,
 
   source = drag ? g_object_get_data (G_OBJECT (drag), "gtk-notebook-drag-origin") : NULL;
 
-  if (!gtk_notebook_can_drag_from (self, source, source->priv->cur_page))
+  if (!source || !gtk_notebook_can_drag_from (self, source, source->priv->cur_page))
     return FALSE;
 
   self->priv->mouse_x = x;