MozReview Statistics July 2015

July 16, 2015 at 02:00 PM | categories: MozReview, Mozilla

As of today, ~15.6% of commits landing in Firefox in July have gone through MozReview or have been produced on machines that have used MozReview. This is still a small percentage of overall commits. But, signs are that the percentage is going up. Last month, about half as many commits exhibited the same signature. It's only July 16 and we've already passed the total from June.

What I find interesting is the differences between commits that have gone through MozReview versus the rest. When you look at the diff statistics (a quick proxy of change size), we find that MozReview commits tend to be smaller. The median adds as reported by diff stat (basically lines that were changed) is 12 for MozReview versus 17 elsewhere. The average is 58 for MozReview versus 100 elsewhere. For number of files modified, MozReview averages 2.59 versus elsewhere's 2.71. (These numbers exclude some specific large commits that appeared to be bulk imports of external projects and drove up the non-MozReview figures.)

It's entirely possible the root cause behind the discrepancy is a side-effect of the population of MozReview users: perhaps MozReview users just write smaller commits. However, I'd like to think it's because MozReview makes it easier to manage multiple commits and people are taking advantage of that (this is an explicit design goal of MozReview). Whatever the root cause, I'm glad diffs are smaller. As I've written about before, smaller commits are easier to review and land, thus enabling projects to move faster.

I have a quarterly goal to remove the requirement for a Mozilla LDAP account to push to MozReview. That will allow first time contributors to use MozReview. This will be a huge win, as we can do much more magic in the MozReview world than we can from vanilla Bugzilla (automatic bug filing, automatic reviewer assignment, etc). Unofficially, I'd like to have more than 50% of Firefox commits go through MozReview by the end of the year.