Re: Application suddenly stuck at startup

[Simon Feltman <s feltman gmail com>]

Hi Jonathan,

I don't know if this is the problem but it looks like there are calls being made directly to a Gtk model within a Python thread which I can't image is ok (specifically in _library_artwork_update which is where the deadlock seems to occur). You might try wrapping the code within that function or any call to Gtk within it with calls to Gdk.threads_enter/exit:

http://developer.gnome.org/gdk/unstable/gdk-Threads.html

Aside from that, I think using Gio instead of attempting to use Python threads and IO mixed with Gtk might help considerably with what you are trying to do.

-Simon

On Thu, Feb 28, 2013 at 8:01 AM, Jonathan Ballet <jon multani info> wrote:

Hi,

I'm developing^Whacking on a Gtk application [1] which uses PyGObject since a few months now. It's a client for the Music Player Daemon (mpd).

Suddenly yesterday, I couldn't run it anymore: when I start it, the application initialization at the very beginning is alright, Gtk.Appliction "activate" signal is triggered and answered as usual, and then, everything hangs. *Something* get stuck *somewhere* and I can't run the application anymore...
I tried to put aside all the things that would come up to my mind, which were: I didn't updated any libraries on my system, I stashed my current changes, I switched back the application to master, "git clean -fdx"'d it, switched off the player daemon, even restarted my computer in case a socket or another daemon was off somewhere, and I quickly patched threading.Thread(), threading.Condition() and GLib.idle_add() so they are just stubs so remove potentially blocking things.

I was just trying a new piece of code (which I reverted since then) and I'm pretty sure I restarted the application just a couple of hours before without any troubles. I used to do it several times a day for weeks, and now, I'm really confused.

So I fired up gdb and had a look at the result (see the attached file), and I would say the application is stuck waiting for gdk_threads_dispatch() to return (which seems to be waiting to get a lock) in the main thread (#1)
(There's another thread, waiting for a Condition to be released, but I'm pretty sure it's not the faulty code since 1. it's in another thread, and 2. it still hangs even if I remove this code).

There are probably tons of places where the application abuses Gtk, threads and stuff, and we are trying to sort things out one at a time, but it used to work OK until now, when I don't have anything anymore.

How can I get a clue on what's happening? I don't know where to look know, and I'm as stuck as my application :(

Any tips appreciated,

 Jonathan

[1]: https://github.com/multani/sonata

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