Bug#999623: python3 gi Notify fails to notify when executed within an idle_add callback

[Dan Stromberg]

Package: python3-giVersion: 3.38.0-2

No error messages are generated; the notification simply does not appear.

The problem exists on a freshly-installed Debian 11.1 system.

Here is an SSCCE that demonstrates the problem:

#!/usr/bin/env python3

"""
Minimal program that replicates the failure to Notify - most of the time.

When I ran this on one system, it consistently failed.
When I ran it on a new system, it succeeded once and then failed
consistently thereafter.
"""

import sys

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk  # noqa: E402
from gi.repository import GLib  # noqa: E402
gi.require_version('Notify', '0.7')  # noqa: disable=E402
from gi.repository import Notify  # pylint: disable=no-name-in-module
# noqa: disable=E402


def notify_by_libnotify():
    """Create a notify-osd popup using gi."""
    Notify.init("sscce")
    notification = Notify.Notification.new('note')
    notification.set_urgency(2)
    notification.show()
    print('notification.show() executed', file=sys.stderr)


window = Gtk.Window(type=Gtk.WindowType.TOPLEVEL)
window.show()
GLib.idle_add(notify_by_libnotify)
Gtk.main()


Thanks!