Tag Archives: git

Day 2 at Mozilla Messaging: pbranch, testing, teleconferencing, intranet, and more testing

Ok, today was my second day at Mozilla Messaging.  Another good day.  Here are some highlights:

Today, I started off my day by wanting to learn a few things:

  1. How to use pbranch to locally commit my Firefox patch from yesterday
  2. How to write tests for my patch using Mochitest

I started with the first one.

So, for the most part, Mozilla uses Mercurial as its distributed version control system.  I’ve been using Git (arguably Mercurial’s main competitor) since last summer with both MarkUs and Review Board.  Mercurial is something quite different.  Quite different indeed.

pbranch is a tool that lets me have a patch queue.  Basically, organization, and re-organization of any changes I make to the Mozilla code-base is a lot easier using something like pbranch.

So I spent a few minutes going through the pbranch tutorial.  Eventually, I think I got the hang of it – basically, for my extension changes-sets, I create a new branch using hg pnew, and commit to that branch.  I’ll keep committing to that, and when I’m all done, I’ll dump my patch to a Bugzilla attachment.  After I pass code review, someone will merge my patch.  Then I’ll remove my local branch and pull in my changes.  Sweet!

Ok, so at this point, I think I got the workflow.  Next, I needed to figure out how to write a Mochitest.  Thankfully, there’s this tutorial.

Looking through the documentation, I was reminded of Selenium a little bit.  I think it’s sort of the same idea.

So how do I write a test for my changes?  Unfortunately, the documentation on how to write a Mochitest is a little thin.  So I started hunting around, looking for examples to extrapolate from.

At some point, I found myself staring at this code.  Wow!  A full-blown API for manipulating the add-ons manager!  Great!  But it turns out that this is for Mozmill tests, and not Mochitests.  But a quick search through MXR showed that nobody was using that add-on manager API.  Argh.

Was I barking up the wrong tree here?  Where the hell were the add-on manager tests?

I quickly swallowed my pride, and decided to talk to an expert.  I used Mercurial’s log function to determine who had changed extensions.js the most.  The name Dave Townsend came up.  According to his site, he’s “Mossop” on IRC, but he wasn’t online.  The log function also mentioned the name Blair McBride.  On IRC, he’s “Unfocused”.  He was online, but unavailable.


It was at this point that Blake told me that the Mozilla Messaging weekly meeting was going to take place.  Apparently this happens every Tuesday at 9:30AM PST.  So we marched over to a conference room, hooked up this super-advanced phone (the phone had a boot-up screen, and then showed the Mozilla logo…whoa!).  A little while later, the meeting began.  The meeting was super fast, and super efficient – especially considering the teams are spread out across the globe.  One person led the meeting, and called the different teams up to give their weekly status.  I also got to introduce myself to the team.  I rambled off something about Thunderbird+Unity and code review, and then stumbled back to my chair.  Cool times.  Anyhow, teleconferencing is going to take some getting used to.

So, with the meeting over, and still no word from Unfocused, I decided to clean up my code a bit, and then posted my patch up on Bugzilla.  I asked Dave Townsend for a code review, and said that if testing needs to happen, hopefully he’d let me know and advise me.

It didn’t take long for a response to come back.  Apparently, there are indeed tests for the add-ons manager, and they’re right here in front of my face.  Crap, I should have known.  :/

So I dove into those tests…wow, there were a lot of them.  And I didn’t have a clue as to how to run any of them.

Following the Mochitest instructions, I eventually tried this:

TEST_PATH=toolkit/mozapps/extensions/test/ make -C $OBJDIR mochitest-plain

(where the TEST_PATH is set to the folder of tests I want to run, and $OBJDIR is an environment variable that points to the objdir compilation folder for Firefox.)

But this only ran a single test out of the bunch, and there were hundreds in there.  So what was the deal?

It turned out that the tests I wanted to run were with higher privileges than your average Mochitest test.  A basic Mochitest test is run using mochitest-plain.  Apparently, I needed to use mochitest-browser-chrome.  Took me a good half-hour to figure that one out.  :/

Anyhow, BAM, I had it – the tests were running.  The bad news:  I had a bunch of failing tests.  The good news:  the same tests failed without any of my changes.  So…great…I guess.

It was at this point in the day that I was given access to the Mozilla Messaging Intranet (the internal wiki).  There was plenty to read there, including something along the lines of “So you’re a new Mozilla Messaging hire”…I gave that a read.  Very interesting.

After that, I subscribed to a few internal mailing lists, and submitted my Mozilla-centric blog feed to be added to Planet Mozilla and Planet Mozilla Messaging.  Woop!

Finally, I got back to testing.  After digging through those add-ons manager tests, I finally found this:  PAYDIRT.

Sweet!  Tons of stuff for free in there:  MockProvider, createAddons… writing tests in there looked like it’d be cake.

But then it was home time.  More tomorrow.

Today, I want to learn a few things:

  1. How to use pbranch to locally commit my Firefox patch from last night
  2. How to write tests for my patch using Mochitest

Lets start with 1:

So Mozilla uses Mercurial as its distributed version control system.  I’ve been using Git since last summer with both MarkUs and Review Board.  Mercurial is something quite different.

Started going through pbranch tutorial.

So for my extension changes, here’s what I’m going to do.  I create a new branch using pnew, and commit to that.  I’ll keep committing to that.  When I’m all done, dump my patch to a Bugzilla attachment.  Someone will merge my patch.  Then I’ll remove my local branch and pull in my changes.  Sweet!

Ok, so I’ve got the workflow (I think).  Next, I need to figure out how to write a Mochitest.  Thankfully, there’s this:  https://developer.mozilla.org/en/Mochitest

I’m reminded of Selenium a little bit.  I think it’s sort of the same idea.

So how do I write a test for my changes?  Unfortunately, the documentation on how to write a Mochitest is a little thin.  So I guess I’ll be looking at examples, and extrapolating from there.  Let’s see if I can find a similar test written elsewhere.

This is promising:  http://mxr.mozilla.org/mozilla-central/source/testing/mozmill/tests/shared-modules/testAddonsAPI.js

Hm…but this is for Mozmill, and not Mochitest.

Yep, Mozilla uses a lot of different testing frameworks.  It’s a little confusing.  Mozmill is also like Selenium

So who is using testAddonsAPI.js?  Argh.  It looks like nobody.

I’m having a hard time finding tests for any of the stuff in extensions.js.  So I guess it’s time to talk to the expert.  I use hg log to see who the most frequent committer is to extensions.js.  The name Dave Townsend comes up.  http://www.oxymoronical.com/ .  He’s Mossop on IRC, and not online.  So who else is listed in hg log?  Blair McBride.

Had my first Mozilla Messaging weekly meeting.  It’s on a phone.  Interesting how its organized…really not like any phone conversation I’ve been a part of.  People mute themselves…unmute when its time to talk.  Awkward pauses are rampant…pretty cool though.  Coordinating around the world.  Nice!

Ok, back to Blair McBride…after a little hunting around, it turns out his IRC nickname is Unfocused.  I’ve found him in a few of the Mozilla IRC channels, and am waiting to hear back from him.

No word.  So, after some scrubbing, I posted my patch up on Bugzilla, and asked Dave Townsend for a review.  If testing needs to happen, hopefully he’ll let me know and advise me.

Whoop, just got a message.  The tests are here:  http://mxr.mozilla.org/mozilla-central/source/toolkit/mozapps/extensions/test/.  Crap, I should have known.  :/

Ok, lets examine those tests… hold up.  How do I run these?  Trying to run that directory with Mochitest, I only get 1 test to run…wtf?

Success!  TEST_PATH=toolkit/mozapps/extensions/test/ make -C . mochitest-browser-chrome

Sweet, so all those tests run.  Bad news though – a bunch of failing tests.  Going to see if it was my patch.  Ok, looks like a bunch of tests were failing before I even committed anything.  That’s good, I guess.

So, I have to compare them in order to ensure that there aren’t MORE failing tests after my patch goes in.

I now have access to the Intranet.  Sweet – lots of stuff to read here.  “So you’re a new Mozilla Messaging hire…”

Just subscribed to a few internal mailing lists, and submitted by Mozilla feed to be added to Planet Mozilla and Planet Mozilla Messaging.  Woop!

Ok, back to testing, I’ve found this:  http://mxr.mozilla.org/mozilla-central/source/toolkit/mozapps/extensions/test/browser/browser_sorting.js  This looks like paydirt.

The CEO of Mozilla Messaging (David Ascher) just welcomed me to MoMo:

mconley: welcome to the madhouse


Sweet!  Tons of stuff for free:  MockProvider, createAddons – I think this’ll be cake tomorrow.

Ooops – Dave Townsend just asked a good question:  what about extensions that are to-be-installed?  to-be-uninstalled?  Where do they go?

I’ll have to check that out tomorrow.

But right now, it’s home time.

ReviewBoard Extensions: A State of Affairs

One of my potential research experiments involves augmenting ReviewBoard, and so, I’ve been studying the ReviewBoard code.

I want to give ReviewBoard the ability to record certain statistics – for example, the number of defects in a review request, number of defects found per reviewer, defect density, inspection rate, etc…

It turns out I’m not the only one who wants this to happen.  Check out this thread.

So it turns out that the devs building ReviewBoard are planning on integrating an extension framework.  Theoretically, users could then write their own extensions to customize ReviewBoard as they see fit.  Think WordPress plugins, but for a code review tool.  Neat.

According to the above link:

A lot of this [extension framework] already exists in a private development branch, and it will be one of our primary focuses as soon as 1.0 goes out.

However, I found the following quote from a relatively recent mailing list message:

[with regards to the extensions framework]…We have to finish building it, testing
it, getting other features we have planned into the release, and performing
the release. So, we’re looking at a year or more. But I don’t see how we’d
get the functionality you want short-term.

Hrmph.  My thinking:  maybe I can help them with it, and we can crank this puppy out sooner.

So where is this private branch?  It actually took a little bit of detective work…

Detective Work

I started by looking at the ReviewBoard repo on Github, which I assumed that the extensions branch would fork from.

I was right – check out the fork network.  There’s a branch helpfully labeled “extensions” forked by davidt, one of the ReviewBoard devs.

Two observations:

  1. This fork hasn’t been updated in about a month
  2. The extensions stuff references stuff from Djblets which doesn’t exist in the Djblets master branch

So I perform the same exercise – I glance at the Djblets fork network, and see the handily named “extensions” fork that is in davidt’s git repo.  Nice.

Ok, so those are the forks/branches that I’m going to grab.

A Fluke

So, funny story:  I was able to get this “extension” version of ReviewBoard working on my work machine.  But it was by a complete fluke – this extension version of Djblets is actually missing some pieces.  The only reason it worked for me was because I accidentally ran with the master checkout of Djblets first.  This errored out, and also generated a bunch of compiled Python.  I then switched to the extensions branch, which left the compiled Python behind.  The compiled Python filled all of the missing pieces that are in the extensions branch of Djblets, and so it ran.

For a guy who is pretty new to both Git and Django, I found that problem pretty frustrating to track down.  Especially when I started writing up the checkout instructions… big thanks to Zuzel for her invaluable (and patient) Django guidance.

Anyhow, if you’re interested in the steps to failure, here they are…

Setting Up (for failure)

I’m running Ubuntu Karmic.  I have Git installed.

  1. First of all, this document is invaluable
  2. Check out django_evolution from SVN to some local directory
  3. Put path to django-evolution into PYTHONPATH (export PYTHONPATH=$PYTHONPATH:/…/django-evolution-read-only/)
  4. Get Python Setuptools (sudo apt-get install python-setuptools)
  5. With easy_install, get nose, paramiko, recaptcha-client, Sphinx (sudo easy_install nose paramiko recaptcha-client sphinx)
  6. Clone original master Djblets repo (git clone git://github.com/djblets/djblets.git) and CD into djblets directory
  7. Add davidt’s remote Djblets branch (git remote add davidt git://github.com/davidt/djblets.git)
  8. Fetch davidt’s repo  (git fetch davidt)
  9. Track davidt’s extension branch for djblets (git branch extensions davidt/extensions)
  10. In djblets root dir, type:  sudo python setup.py develop
  11. This should install Django too.  The ReviewBoard install doc says to install from Subversion, but this will do for now.
  12. Clone ReviewBoard git repo (git clone git://github.com/reviewboard/reviewboard.git) and Cd into it
  13. Add davidt’s remote Reviewboard branch (git remote add davidt git://github.com/davidt/reviewboard.git)
  14. Fetch davidt’s repo  (git fetch davidt)
  15. Track davidt’s extensions branch of reviewboard (git branch extensions davidt/extensions)
  16. Switch to extensions branch (git checkout extensions)
  17. So reviewboard/reviewboard/extensions should have stuff in it.
  18. python ./contrib/internal/prepare-dev.py
  19. Manually create the directory reviewboard/reviewboard/htdocs/media/ext.  ReviewBoard expects it and will complain if it isn’t there.
  20. Run ./contrib/internal/devserver.sh
  21. Go to localhost:8080

If you’re like me, you’ll see an error about “no module named urls”.  This is because the extension branch of Djblets is missing urls.py in its djblets/log directory.  As you can see, urls.py exists in the master Djblets branch.

So I’ve accidentally got it running.  But this version of ReviewBoard I’ve created is like Frankenstein’s monster – it’s a sad, stitched together monstrosity that should probably never see the light of day.

I tried to merge the master branch of Djblets and ReviewBoard into the extensions branch, and then realized that I had no idea what I was doing.  The last guy you want doing a merge is a guy who doesn’t know what he’s doing.

So that’s where I stand with it.  Kind of a sad affair, really.  I’ve posted on the ReviewBoard developer mailing list asking for some guidance, but all is quiet so far.

In the meantime, I’ll continue studying the code when I can.  The extensions stuff is actually pretty far along, in my opinion – but what do I know, I’ve never built one.  I’ll also take a peek at some other examples of extension frameworks to see what I can learn about implementation (that’s right – I’m talking about you, WordPress).

I’ll let you know what I find.