[meld/ui-next] filediff: Handle opening files from blank start

[Kai Willadsen <kaiw src gnome org>]

commit 0362986b40c72e58a48d5e268365f718da072e43
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Mar 24 07:39:23 2019 +1000

    filediff: Handle opening files from blank start

 meld/filediff.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/meld/filediff.py b/meld/filediff.py
index 0ee4a729..9c0467e2 100644
--- a/meld/filediff.py
+++ b/meld/filediff.py
@@ -1903,7 +1903,8 @@ class FileDiff(Gtk.VBox, MeldDoc):
             title=_("Open File"),
             transient_for=self.get_toplevel(),
         )
-        dialog.set_file(self.textbuffer[pane].data.gfile)
+        if self.textbuffer[pane].data.gfile:
+            dialog.set_file(self.textbuffer[pane].data.gfile)
         response = dialog.run()
         gfile = dialog.get_file()
         encoding = dialog.get_encoding()