Ticket #117 (defect)

Opened 2 years ago

Last modified 2 years ago

Null tstate with notify-python and threading

Status: new

Reported by: dgoodwin@dangerouslyinc.com Assigned to: chipx86
Priority: normal Milestone:
Component: notify-python Version:
Severity: normal Keywords: pynotify add_action assertion tstate failed
Cc: gallegosja@gmail.com D-BUS Version:
Patch Included: 0 OS/Distro Version: Fedora Core 6 x86_64

I'm not certain if I'm onto a bug here or just bad code on our end, but we have a program that uses notify-python for displaying user notifications, and started crashing after the user clicks a button in the notification bubble after we introduced threading.

To debug the problem I started putting together the smallest piece of code possible that I could replicate the error with. 

#!/usr/bin/env python
import pynotify
from egg import trayicon
import gtk
gtk.gdk.threads_init()

def accept(self, notification, action):
    print "accepted"

if __name__ == "__main__":
    tray_icon = trayicon.TrayIcon("testicon")
    tray_image = gtk.Image()
    tray_image.set_from_stock(gtk.STOCK_DIALOG_INFO, 
        gtk.ICON_SIZE_SMALL_TOOLBAR)
    event_box = gtk.EventBox()
    event_box.add(tray_image)
    tray_icon.add(event_box)
    tray_icon.show_all()

    pynotify.init("Title")
    notify = pynotify.Notification("Title", "Hello world!")
    notify.attach_to_widget(tray_icon)
    notify.set_timeout(0)
    notify.add_action('accept', 'Accept', accept)
    notify.show()

    gtk.main()

This fails as soon as the user presses the "Accept" button (i.e. before reaching the callback) with the following exception on Fedora Core 6 x86_64:

python: Python/ceval.c:2531: PyEval_EvalCodeEx: Assertion `tstate != ((void *)0)' failed.

I tested this on Ubuntu Egdy i386 running within Vmware and saw a similar result, although this time just a segfault and not as informative a message, I suspect the problem is the same.

Note that commenting out the threads_init() call will allow the program to function properly, as soon as that line alone is added the error begins to happen.

I also tried a version of the code where the notification was displayed from within a seperate thread, but the result was the same. For this I used a modified version of this program similar to that of this article: http://aruiz.typepad.com/siliconisland/2006/04/threads_on_pygt.html

After this I began to wonder if there might be a bug with notify-python and threading, although I'm aware most programmers like to think the bug is anywhere but their own code. :) Anyhow I thought I should submit the potential problem just the same.

Cheers.

Change History

04/27/07 14:22:49: Modified by kad

  • cc set to gallegosja@gmail.com.
  • keywords set to pynotify add_action assertion tstate failed.

Well, yeah I'm having the same problem. Same error actually, this from a fedora 6 box, another thing, can we put a callback within a class? so far I've only seen calls to defs outside of classes... for example, the following code doesn't work (being part of a class, obviously): 

def echo(self, n, action):
    print "hello"

def alert(self, title, message):
    n = pynotify.Notification(title, message, gtk.STOCK_DIALOG_WARNING)
    n.set_timeout(0)
    n.add_action("extend", "Extend task", self.echo)
    n.show()

But making the Notification object a part of the class borks with the same error reported above. 

def alert(self, title, message):
    self.n = pynotify.Notification(title, message, gtk.STOCK_DIALOG_WARNING)
    self.n.set_timeout(0)
    self.n.add_action("extend", "Extend task", self.echo)
    self.n.show()

So I guess the correct way to do it is the second, but it raises an error.