In November 2014, Emacs switched version control systems from Bazaar (aka bzr) to git. There were two main reasons: 1) bzr has kinda stopped development, and 2) using a version control system that more people are familiar with might attract more developers.
On the other hand, git is really, really finicky, and bzr is arguably superior to git in many works flows. Perhaps switching to git would scare away some Emacs developers who just couldn’t be bothered?
It’s now April 2015, so five months have passed, and I whipped up a teensy script to tally the number of patch authors per month, and then plotted the results.
The red line denotes the changeover.
First of all, it’s amusing that we have a timeline going back to 1988, but I would suspect that the numbers before, say, 2007 are too low because maintainers would commit patches with themselves as the “author”, I think. (Edit: Eli Zaretskii says the numbers should be accurate throughout the timeline.)
But the most recent years should be kinda reliable:
Uhm… Well, attracting droves of new developers didn’t happen, apparently. Except for the spike the month git was introduced, we’re within the normal range of developers, I think.
Anything interesting pop up if we count commits per month instead of contributors per month?
Not really — same story.
What about the number of people who commit patches to the Emacs repository?
That does look like a possible uptick.
So… was the changeover worth it? Probably. But the impact was a bit over-sold on both sides, I think.