g-i: mark GtkSnapshot to_(node|paintable) as nullable
Fixes an upstream issue reported at https://github.com/gtk-rs/gtk4-rs/issues/845
Can be checked with
from gi import require_version
require_version('Gtk', '4.0')
from gi.repository import Gtk, Gio
def on_clicked(button):
snapshot = Gtk.Snapshot.new()
node = snapshot.to_node()
assert(node != None)
def on_activate(app):
window = Gtk.ApplicationWindow.new(app)
window.set_title("Test case")
button = Gtk.Button.new_with_label("Test case")
button.connect("clicked", on_clicked)
window.set_child(button)
window.show()
def main():
app = Gtk.Application.new("gtk4test.gtk4test", Gio.ApplicationFlags.FLAGS_NONE)
app.connect("activate", on_activate)
app.run()
main()