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Yesterday, GUADEC hosted a PyGObject hackfest. I was really happy to see so many participants, and a lot of whom who are rather new to the project. I originally feared that it would just be the core crew of four people, as this is not exactly the shiniest part of GNOME development.

So I did not work on the stuff I was planning for, but instead walked around and provided mentoring, help, and patch review. Unfortunately I do not know all the results from the participants, hopefully they will blog some details themselves. But this is what I was involved in:

  • Manuel Quiñones added an gtk_tree_view_column_set_attributes() override (the original C function uses varargs and thus is not introspectable). Most time was spent figuring out an appropriate test case.
  • I showed Didier Roche some tricks about porting a pygtk application to PyGI/GTK3. He gave a shot to porting Meld, but unfortunately it uses a lot of pygtk hacks/tricks, most of which are obsolete now. So this proved too big a project for one day eventually :-(
  • Paolo and I guided Marta Maria Casetti, one of this year’s GNOME GSoC students, through her first pygobject patch. The test case still needs some love (again, nothing regarding GtkTreeView is easy), but the actual patch is good. Thanks Marta for participating, and not getting intimidated by all the new stuff!
  • While working on above patch, Marta encountered a rather curious TypeError: Expected Gtk.TreeViewColumn, but got GObjectMeta when writing the override. What seemed to be a trivial problem at first quickly turned into an one-hour debugging session involving grandmaster John Palmieri and me, with others chipping in as well. In the end it (of course!) turned out to be a trivial four-character change in Marta’s patch, but it was fun to get to understand the problem (a loong-forgotten special case of overrides resolution in overrides code). Now pygobject gives a proper error message which is actually helpful, i. e. which argument causes the problem and which module/class/method is provided, which should prevent us from being misguided into the totally wrong direction the next time this happens.
  • John Stowers got the Windows build working again, and showed off the gtk-demo under Windows. This is really amazing, I hope we can get that into trunk soon and not let it bitrot again for so long. Thanks!
  • Simon and Manuel worked on porting some Sugar extensions. Together with Paolo we also discussed the GStreamer 1.0 API a bit, which parts can become API additions and which need to become overrides.
  • Michal Hruby debugged a leak in the handling of GVariant arrays when using libdee.

Thanks everyone for participating! I hope everyone enjoyed it and got to learn a new thing or two. See you at the next one!

PyGObject hackfest at GUADEC 2012

PyGObject hackfest at GUADEC 2012

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I have had the pleasure of attending GUADEC in full this year. TL;DR: A lot of great presentations + lots of hall conversations about QA stuff + the obligatory be{er,ach} = ?.

Last year I just went to the hackfest, and I never made it to any previous one, so GUADEC 2012 was a kind of first-time experience for me. It was great to put some faces and personal impressions to a lot of the people I have worked with for many years, as well as catching up with others that I did meet before.

I discussed various hardware/software testing stuff with Colin Walters, Matthias Clasen, Lennart Poettering, Bertrand Lorentz, and others, so I have a better idea how to proceed with automated testing in plumbing and GNOME now. It was also really nice to meet my fellow PyGObject co-maintainer Paolo Borelli, as well as seeing Simon Schampier and Ignacio Casal Quinteiro again.

No need to replicate the whole schedule here (see for yourself on the interwebs), so I just want to point out some personal highlights in the presentations:

  • Jacob Appelbaum’s keynote about Tor brought up some surprising facts about how the project has outgrown its past performance problems and how useful it was during e. g. the Arab revolution
  • .

  • Philip Whitnall’s presented Bendy Bus, a tool to mock D-Bus services for both unit and fuzz testing. He successfully used it to find and replicate bugs in Evolution (by mocking evolution-data-server) as well as libfolks (by mocking the telepathy daemons). It should work just as well to mock system services like upower or NetworkManager to test the UI bits that use it. This is a topic which has been on my wishlist for a long time already, so I’m happy that there is already an existing solution out there. We might have to add some small features to it, but it’s by and large what I had in mind, and in the discussion afterwards Philip said he’d appreciate patches against it.
  • Christophe Fergeau showed how to easily do Windows builds and installers from GNOME tarballs with MinGW-w64, without having to actually touch/use Windows (using cross-building and running tests etc. under wine). I found it surprising how easy that actually is, and it should not be hard to integrate that in a jhbuild-like setup, so that it does not keep breaking every time.
  • Colin Walters gave an introduction to OSTree, a project to build bootable images from kernel/plumbing/desktop upstream git heads on a daily basis. This is mostly to avoid the long delays that we otherwise have with doing upstream releases, packaging them, and getting them into a form that can safely be tested by users. In an afterwards discussion we threw some ideas around how we can integrate existing and future tests into this (something in spirit like our autopkgtest). This will be the area where I’ll put most focus on in the next time.
  • Adam Dingle of yorba fame shared his thoughts about how we can crowdfunding of Free Software Projects work in practice, comparing efforts like codefoundry and kickstarter. Of course he does not have a solution for this yet, but he raised some interesting concerns and it spun off lots of good discussions over lunchtime.
  • Last but not least, the sport event on Saturday evening was awesome! In hindsight I was happy to not have signed up for soccer, as people like Bastian or Jordi played this really seriously. I participated in the Basketball competition instead, which was the right mix of fun and competition without seriously trying to hurt each other. :-)

There were a lot of other good ones, some of them technical and some amusing and enlightening, such as Frederico’s review of the history of GNOME.

On Monday I prepared and participated in a PyGObject hackfest, but I’ll blog about this separately.

I want to thank all presenters for the excellent program, as well as the tireless GUADEC organizer team for making everything so smooth and working flawlessly! Great Job, and see you again in Strasbourg or Brno!

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I started to collect some easy PyGObject bugs which are appropriate for the PyGObject hackfest at GUADEC on July 30th. These are bugs which do not need a lot of previous knowlege and are excellent starters for new contributors, such as adding overrides, fixing build system issues, etc.

I also created an initial idea pool/agenda/coordination page, where participants can add or signup for things to work on.

Feel free to add your own topics! I’m really looking forward to GUADEC and the hackfest, see you there!


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I just received confirmation that my request for a PyGObject hackfest has been approved by the GUADEC organizers.

If you are developing GObject-introspection based Python applications and have some problems with PyGObject, this is the time and place to get to know each other, getting bugs fixed, learn about pygobject’s innards, or update libraries to become introspectable. I will prepare a list of easy things to look into if you are interested in learning about and getting involved in PyGObject’s development.

See you on July 30th in A Coruña!


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