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Regression range finder for Mozilla nightly builds
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mozregression is an interactive regression range finder for Mozilla nightly and inbound builds.


Please keep in mind that you need python 2 to get it working. Accordingly you will have to install the relevant version of pip. Depending upon your setup, the script might be called pip or pip2 (or may be something else).

you can install mozregression with setuptools or pip. OS-specific instructions

easy_install mozregression


To find the regression range for a bug, supply mozregression with the date of the last known good nightly and the date of a bad nightly (optional):

mozregression --good=2010-03-16 --bad=2010-09-08

This will download and run several nightly builds on new profiles and narrow down the range. After checking a few nightlies, you'll get the regression range which looks something like this:

Last good nightly: 2010-09-08
First bad nightly: 2010-09-09


other options

Just run the nightly for a particular date:

moznightly --date=2010-10-23

Find regression range on Thunderbird nightlies:

mozregression --app=thunderbird

Find regression range on Firefox mobile nightlies:

mozregression --app=fennec

Other branches/repos:

mozregression --repo=mozilla-1.9.2

Other options exist for running the nightlies with a particular profile, addons, and browser arguments.


mozregression uses mozcommitbuilder:

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