The surprise isn't that Perl's commit rate declines at all - it's that the decline seems to be so much sharper than that of other languages. A number of dedicated Perl programmers have fixated on that one speculative aside in my post - in fact, this is the first blog post I've ever written that has garnered me some genuinely nasty email. Perhaps a sign of a wee bit of defensiveness in the Perl community at the moment?
A number of people have argued that Perl projects somehow approach completion more quickly than other projects, and that this explains the decline. I'm pondering ways to test this idea from the data, but I must say that it sounds pretty implausible to me.
> I'm pondering ways to test this idea from the data, but I must say that it sounds pretty implausible to me.
It sounds exactly right to me, if you consider that some 21,000 of those Perl projects are CPAN distributions. There's a very strong bias among CPAN contributors to building small, reusable tools. I am the primary developer of some 30 of those Perl 5 projects. My commit rate has followed the graph of several commits in the initial stages, then very few after a year or eighteen months because the projects entered bugfix-only maintenance mode.
> Perhaps a sign of a wee bit of defensiveness in the Perl community at the moment?
You made some flippant provocative statements apparently based on poor assumptions unsupported by any of the evidence you presented. What did you expect?
What surprises me is that NONE of my charming Perl correspondents have argued that the Github data is simply atypical. As I point out in my post, it's not just possible, it's likely that this is the case. Instead, every single one has claimed with the type of absolute certainty you can only achieve by having no data at all that it's due to CPAN, and some magical tendency towards completeness that it imparts to projects... Again, I think it's implausible, but I'm open to suggestions of ways to settle the matter with actual data.
Given the huge jump in the number of Perl projects available on GitHub thanks to the recent BackPAN import, it's a reasonable conclusion. Likewise the commit history; CPAN's fourteen years old.
> ... charming ... the type of absolute certainty you can only achieve by having no data at all ... some magical tendency...
You'll have a much more fruitful discussion without this condescension.
> I'm open to suggestions of ways to settle the matter with actual data.
Easy suggestion: find the percentage of Perl projects in your study that came from the BackPAN import. See if they match the experiences of the CPAN contributors who've offered explanations.
It's genuinely difficult to avoid being condescending given the type of conversations I've been having about this. For what it's worth, it's not aimed at you specifically.
At any rate, I'm happy to ditch the snark, and talk about something concrete. I'm not sure what your suggestion is - I could separate out the CPAN projects (is there any way to do this programmatically?), and see if they show a greater decline in commits than non-CPAN Perl projects. But that wouldn't settle the issue, because I would still need some way to distinguish between projects that have decreasing commits because developer impetus is petering out as projects become more unwieldy, and projects that have decreasing commits because they are nearing "completion".
I would also want to compare the results with an equivalent set of Python or Ruby libaries - choosing an appropriate set would be tricky.
A number of people have argued that Perl projects somehow approach completion more quickly than other projects, and that this explains the decline. I'm pondering ways to test this idea from the data, but I must say that it sounds pretty implausible to me.