root_context_menu.parent is None

[loicpw]

Hi,

I think I found a bug in context_menu: here's the scenario:

I am creating a context menu which I'm using on nodes of a TreeView, and had a crash that appeared randomly.

I'm using the same context menu instance for all the nodes of my TreeView.

The context menu is initially added to the top layout, which is a FloatLayout object, here is the code:
(note I had to add some code to fix a weird behaviour as well, which is apprently not related, I don't know if it's because I'm not using it the right way or if it's a bug)

class TreeContextMenu(ContextMenu):
    def __init__(self, *args, **kw):
        super().__init__(*args, **kw)
        app= App.get_running_app()
        rw = app.root
        self.cancel_handler_widget = rw
        rw.add_widget(self)

        # bug workaround (otherwise keep showing the menu in the bottom) ?
        self.visible = True
        self.hide()

when calling the menu (on right click on the nodes of my treeview with super().show(*app.root_window.mouse_pos)), I had the following crash, but only in some circumstances:

[...]/context_menu.py", line 211, in show_submenu
     self.get_submenu().show(*self._root_parent.to_local(x, y))
 AttributeError: 'NoneType' object has no attribute 'to_local'

I figured out it was because root_context_menu.parent was None in get_context_menu_root_parent method of ContextMenu.

The following code seems to fix the problem, using root_context_menu.orig_parent if root_context_menu.parent is None:

def get_context_menu_root_parent(self):
        """
        Return the bounding box widget for positioning sub menus. By default it's root context menu's parent.
        """
        if self.bounding_box_widget is not None:
            return self.bounding_box_widget
        root_context_menu = self._get_root_context_menu()

        # --------------------------------------------- #
        # ORIGINAL CODE
        # --------------------------------------------- #
        #return root_context_menu.bounding_box_widget if root_context_menu.bounding_box_widget else root_context_menu.parent

        # --------------------------------------------- #
        # FIX
        # --------------------------------------------- #
        if root_context_menu.bounding_box_widget:
            return root_context_menu.bounding_box_widget
        else:
            if root_context_menu.parent is None:
                assert root_context_menu.orig_parent
                return root_context_menu.orig_parent
            return root_context_menu.parent

Thanks