November Bug Squash Month: GJS

Here’s what happened during November Bug Squash Month in GJS.

First off, I didn’t really get on the ball to promote Bug Squash Month and I didn’t take pictures of any bug squashing activity… which I regret. I hope this post can make up for some of that.

During November I finally took the leap and offered to become a maintainer of GJS. My employer Endless has been sponsoring work on bugs 742249 and 751252, porting GJS’s Javascript engine from SpiderMonkey 24 to SpiderMonkey 31. But aside from that I had been getting interested in contributing more to it, and outside of work I did a bunch of maintenance work modernizing the Autotools scripts and getting it to compile without warnings. From there it was a small step to officially volunteering.

With not much of November remaining and a holiday and family visit coming up (life always is more important than bug squashing!) I decided to start out my bug-squashing campaign with what would get me the most results for the time spent: going through GJS’s bug tracker and closing obsolete or invalid bugs. This I managed to do, closing about 1/4 of all open bugs!

Then I made a list of all open bugs with attached patches and intended to review them to see if they still applied and why they hadn’t been committed yet. I got through a few, and had the dubious distinction of fixing up and committing patches from a 7 year old bug yesterday. But as you can see in the list, there are still 54 remaining. A good to-do list for the next Bug Squash Month, or whenever I feel like working on GJS but don’t know what to work on!

Did you know Bugzilla could generate graphs? I didn’t! Here’s a graph of the total bug count in GJS during November Bug Squash Month:


The clunkiness of this chart kills me though…

My plans now that Bug Squash Month is over are to concentrate on fixing things that make it more pleasant to use and contribute to GJS:

  • Find an active co-maintainer so that we can review each other’s patches (could this be you?)
  • Make ES6 Promises available (this work is also being sponsored by Endless)
  • Rework the test suite to use an embedded copy of Jasmine so that writing automated tests becomes less of a pain
  • Find ways to bring in some of the conveniences that Node developers are used to

I’ve also decided to try an experiment: I’ve just made the Trello board public on which I keep track of what I’m working on and what I’d like to work on. Let me know if this is interesting to you and what features you might like to see on there! (It’s made possible by a Chrome extension, Bug 2 Trello.)

All in all November Bug Squash Month was a success, though next time I will get started earlier in the month. Come join me next time!



GJS and Autoconf

Here’s a leftover from the GNOME Developer Experience Hackfest that I participated in back in January: in my last post about it, I mentioned I had worked on some Autoconf macros for GJS that got added to the Autoconf Archive.

My plan was to port an existing GNOME application written in GJS to use the new macros, as an example for other projects to follow. I did so for GNOME Documents a while ago, but then forgot all about it as the patches sat spoiling on my hard drive. Recently I fixed that up and submitted a patch as I should have done long ago.

Here’s the guide to using the new macros in your project:

  • Replace any AC_PATH_PROG([GJS], [gjs]) (or, possibly, pkg-config --variable=gjs_console gjs-1.0; I might add this to the macro) with the shorter AX_PROG_GJS.
  • Use AX_CHECK_GIRS_GJS to check that you have the correct API version of each introspected dependency that you import in your code. Easy rule of thumb in a one-liner: git grep imports\.gi\. | cut -d: -f2 | awk '{$1=$1};1' | sort | uniq will pick out all the GIRs that you import. (Take special note for Cairo: its GIR name starts with a lowercase letter!)
  • Since GIRs don’t have a concept of versions other than the API version, use AX_CHECK_GIR_SYMBOLS_GJS to check for APIs that you use that aren’t available in all versions. For example, if you use the new GtkShortcutsWindow in your code, don’t try to check for GTK 3.20; instead check for the ShortcutsWindow symbol using this macro. (Use this sparingly, of course; there’s no need to check exhaustively for every new API that was added since 3.0, only the latest that you use!)

You might ask “why should I check these dependencies at build-time when they are only necessary at runtime?” You would be correct, it’s not necessary to check them at build time. However, these macros were originally born of the frustration that happens when you “make all install” a tarball only to run it and find out you’re missing GIR dependencies. And especially in the case of using new API, like ShortcutsWindow that I mentioned above, your program might even start up correctly and crash halfway through when you try to open a ShortcutsWindow. It’s a courtesy to your users (not to mention downstream operating system packagers, for whom your runtime dependencies might not be obvious.)

The macros are now also available in your JHbuild setup, through the m4-common module. How that module works is not very discoverable, and Philip W was kind enough to explain it to me when I asked how to get the new macros in. So I’ll explain it again here for future reference.

M4-common contains the agreed-upon set of M4 macros from the Autoconf Archive that GNOME applications use for building. It’s a Git repository that pulls in a known version of the Autoconf Archive as a Git submodule, and installs the M4 macros from it that GNOME applications need to build. If your application uses any of these macros, then it should have a dependency on m4-common in JHbuild.

As written on the GNOME Wiki, if you get an error like

./configure: line 12053: syntax error near unexpected token `GOBJECT_INTROSPECTION_CHECK'

then you probably need to build m4-common and make sure you have a dependency on it.

Note that you don’t need to care about any of that if you’re building from a released tarball; that’s because Autotools bundles all the macros you use in the tarball when you run “make dist”.

Thanks to Philip Withnall and Cosimo Cecchi for code review and good ideas; and thanks to Endless Computers for allowing me to contribute these macros developed on company time to the Autoconf Archive.

Documentation for GJS

In the last days of January I attended the GNOME Developer Experience hackfest, remotely. This was a first for me since I have not attended a hackfest remotely before. It was also a first for the hackfest, that three remote participants signed up, and we had a discussion on desktop-devel-list as to how that should work.

My main project for the three days was to show people the documentation browser I’ve been working on. This got started a while after last year’s edition of the DX hackfest, which I didn’t attend, but the project was born out of a discussion with some people who were there and talked about it last year.

Some background: You can write applications for the GNOME desktop in many different programming languages, including C, Python, Javascript, and Vala; this is made possible through a piece of software called GObject Introspection, which is a bridge between C libraries and many other programming languages. At (yet another) DX hackfest, the one in 2013, GNOME decided to promote Javascript (and the GJS interpreter, which is basically the Javascript engine from Firefox 24 with GObject Introspection on top) as its preferred platform for application development. Not the exclusive platform, you can still develop apps in Python if you want, but there would be a focus on getting new developers started in Javascript, with tutorials and documentation.

Sadly, since then, we haven’t had good API documentation for developing apps in GJS. The best story we had for a long time was to tell people to refer to the C, Python, or Vala API references and mentally make the transition to Javascript, a process I’ve compared to playing a song on the guitar using chord sheets from the internet, but mentally transposing them to a different key as you go along. At one point, Giovanni Campagna generated some static Javascript documentation and hosted it on his website. This eventually got out of date.

So, this was the problem I was hoping to solve. After a short-lived attempt to write my own web app using Semantic UI (a technology I’d still like to check out someday!) I figured, why bother when there was something that would fit the bill perfectly well: DevDocs, an open-source documentation browser that combines all kinds of documentation from elsewhere (mostly web development technologies) and presents them in a unified fashion with a useful but simple and elegant web app.

In the final quarter of 2015 I worked on this on and off, adding some code to the documentation generator g-ir-doc-tool to make its output suitable for DevDocs to input, and some code to a forked version of DevDocs to import the GNOME documentation and make nice metadata and sidebar entries.

Screenshot of Javascript documentation on DevDocs

Here it is in action

At the hackfest I gave a demo (at 6:30 AM, because of the timezone difference!) to the other people there who were working on developer documentation. I got some good feedback from the people who were listening, discussed some of the shortcomings, and we discussed Mathieu Duponchelle’s new documentation tool, Hotdoc, as well. One good outcome was that the GNOME Developer Center now links to my instance of DevDocs (noting that it’s “experimental”.)

To talk about one of the limitations that we discussed at the hackfest: The approach I chose generates all the documentation from one file, the “GIR file,” which is the same approach that g-ir-doc-tool has always taken. This is nice because it’s self-contained, but also incomplete: API references often include separate pages not connected to any API in particular, such as this one. I think using Hotdoc will help overcome this limitation, since Hotdoc is made for combining these sorts of things. I’m also happy not to work with g-ir-doc-tool since all the stuff I added to it was basically bolted on the side, not really useful for anything else, and therefore not likely to be accepted upstream.

I’m now hosting an instance of the GNOME Javascript API documentation on my modified version of DevDocs: try it out at

During the hackfest I also collaborated with Philip Withnall on some autoconf macros for GJS and GObject Introspection, which I’ll talk about in a following post…

Some of the other stuff that people worked on is summarized on Philip W.’s blog.

Endless is Here

For the past 2.5 years I’ve been working at Endless Mobile on something that was mostly secret. You probably caught me being vague about “computers for developing countries.” Well, secret no longer. I am excited, proud, and honestly a bit relieved to be able to say that I can finally tell you what it’s all about.

“Tell you” is a bit of an exaggeration, I’ll let the videomaking skills of my coworker Taylor Morgan show you instead. The video is at the top of our Kickstarter campaign.

We’re launching our first product, via Kickstarter. It’s a computer that’s affordable for people in developing countries, and it looks like this:

Endless One

Alien Egg

I’ve been working on writing applications for this computer, and also contributing to some parts of the operating system. Some parts of this are open source, and you can view them on GitHub.

Also, I have colleagues who are really fun to work with. If you happen to like fun and are looking for a job, there are some positions open… (It’s at the bottom of that page.)

Update: Within only four days, the Kickstarter campaign hit the original goal of US$100 000. It’s incredible. My favorite part is that almost $30 000 of that money was donated by people paying to give a computer, rather than buy one for themselves. Enough people asked for the option to donate a computer directly, so it was added. Also you can now get the whole package for yourself: computer plus swag, because enough people asked for that too.


Hacking the context menu on Windows

I use Gedit, my favorite text editor, even on Windows. Often I just want to use it to see what’s inside some text file that doesn’t have a “.txt” extension, but the way to do that on Windows XP is just simply brain-dead:

  • Right click.
  • “Open”.
  • See a dialog claiming that “Windows cannot open this file.” LIES! ALL LIES!
  • Click “Select the program from a list.”
  • Scroll scroll scroll through a huge-ass list until you get to Gedit.

This is one of those little annoyances that make working with computers unpleasant, so the other day I resolved to fix it. The information in the first Google screenful was sketchy and I had to patch it together, so I know for certain that next time I have to do it, I won’t remember what I did. Hence this post. Of course, it will work with any other program than Gedit too, so hopefully this will be helpful to somebody.

The easiest way is to put a link to the Gedit executable in C:\Documents and Settings\<username>\SendTo. That way, Gedit will show up in the Send To menu when you right-click on a file. But there’s a better way for even lazier people:

Open Regedit (Windows+R, regedit, enter) and go to HKEY_CLASSES_ROOT/*/shell. The “shell” key didn’t exist at first, so I had to create it. Then under the “shell” key, just create a new key and call it “Open with Gedit” or whatever you want the menu item to be.

Then create a new key under “Open with Gedit” and call it “command”, with a lowercase ‘c’. Double click on the “(Default)” value in it, and enter

C:\Program Files\Gedit\bin\gedit.exe "%1"

or wherever your Gedit executable is located. I found that leaving out the quotes around “%1” also works, but then the filename displayed in Gedit is mangled to fit 8.3, like “ELECTR~5.CSV”.

After reciting this incantation, you can right-click on any file and there it is, “Open with Gedit”. Wow, that was the easiest, and not at all obscure, piece of cake ever!