Learn To Hack Firefox Notes

hackFirefox.md

Baked Firefox, For the Busy Cook.

Or, how to make make a Telemetry Probe Cake, using modern kitchen techniques.

Mise en Place

Good prep is 90% of success in cooking.

Original recipe: https://developer.mozilla.org/en-US/docs/Simple_Firefox_build

Slow cookers:

1. Get a modern OSX (10.9+). (or windows) (1-2 hours)
2. Get XCode from https://itunes.apple.com/us/app/xcode/id497799835# (1 hour)
3. https://developer.mozilla.org/en-US/docs/Simple_Firefox_build
4. Get mach (the Mozilla build helper)

   curl https://hg.mozilla.org/mozilla-central/raw-file/default/python/mozboot/bin/bootstrap.py > bootstrap.py && python bootstrap.py
   

5. Checkout mozilla-central (1 hour+) OR try bash InitFromBundle.sh (untested)

mkdir -p ~/hgs/ && cd ~/hgs
hg clone https://hg.mozilla.org/mozilla-central && cd mozilla-central

First Compile.

./mach build
# this will take an hour

./mach run --profile aProfile

Now relax. You have a working Firefox

Attacking a Bug

We are going to fix a telemetry bug.

Claim: SEARCH_DEFAULT_ENGINE should be a count var, not a flag

Filing the Bug

(I like do to this at bugzilla. However, bzexport can also file bugs.)

Fixing the Bug

Prove it's a problem.

Test Script:

let Probe = Services.telemetry.getKeyedHistogramById("")...

// change default engine a few times

// get counts back.

Edit!

1. In your editor, edit toolkit/components/telemetry/Histograms.json.

2. Partial Recompile, and run.:

./mach build toolkit/componenents/telemetry
./mach run --profile aProfile

Verify!

about:addons  (or scratchpad)
let S = Services.telemetry.getKeyedHistogramById

// re-run the local script.

Asking for feedback (bzexport)

bzexport

Asking for review

Do it from bzexport, or from the website

InitFromBundle.sh

set -x nounset

# init from bundle

# https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Source_Code/Mercurial/Bundles

cat << END
0. Warnings:

- will need a few GB of space.  Repo is big.

END

## could be a case block for 'which'
echo "1. this might take 10 mins or so.  watch 'Time Left' below"

## should this only 'reget?'  maybe with 'forced override'
curl "http://ftp.mozilla.org/pub/mozilla.org/firefox/bundles/mozilla-central.hg" -o "/tmp/mozilla-central.hg"

# 1. Initialize a new repository (in a directory called mozilla-central here):

# fail if it exists?
mkdir mozilla-central
hg init mozilla-central

# 2. Un-bundle the bundle file to that repository:
#To use the below command in Windows, export the \path\to\hg and invoke the command from command prompt.

echo "2. Get comfortable. Grab a coffee (or your favorite tasty beverage). Maybe a nap. This unbundling process is going to take quite a lot of time."

cd mozilla-central
hg unbundle /tmp/mozilla-central.hg


echo "3. Adding the following lines to the file mozilla-central/.hg/hgrc (you may have to create it) so that Mercurial will automatically know where to pull changes from future updates."

cat >> .hg/hgrc << END
[paths]
default = https://hg.mozilla.org/mozilla-central/
END

# 4. Establish trusted users and groups so that Mercurial knows that the user root and group root are legitimate, by adding the following lines to the file /etc/mercurial/hgrc.d/trust.rc:
echo "4. there is no 4."

# [trusted]
# groups = root
# users = root
#

echo "5. Update the repository to get all the changes since the bundle was created (this step also doubles as a check of the bundle integrity since if its contents are not exactly the same as what's in the official repository then the hg pull will fail):"

hg pull

echo "6. Check out a working copy from your new up to date repository:"

hg update

cat << END
7.  You should be all set.

cd mozilla-central  # then hack away!
END