| > No bugs fixed At this point, I've helped port multiple code-bases in multiple companies. Porting to Python 3 actually can and does fix some bugs, as it generally forces the code to start handling text semi-correctly, instead of just hoping the bytes go through and it all works out. > Your downstream customers receive very little benefit for this effort, They do, actually. Again, while I was porting those same code-bases, I'm working with a team of engineers who (and along with myself) are also still adding code to meet other incoming requirements. And in my experience, there was a fair bit of "Boy, it'd be nice if X were easier in Python!" where X is something that is easy in Python … 3. The question would have often gone unanswered had we not had devs experienced with Python 3 on the team. Porting to 3 gets you all the additions that have come to Python that haven't been backported. A better standard library, syntax that better supports you, etc., translate to better productivity for devs as they are now equipped with better tools. This is only going to get worse as libraries drop support for 2. (And while many things have been backported into third-party libraries, not all of them have, and in particular, syntax changes. And the existing backports are actually quite useful during the process of porting: I can change the code to conditionally depend on the backport library in 2, and use the real deal in 3.) |
It is not universally applicable, however. There's a lot of old code that, as I said before, is just fine. Adding a 100 line feature in the old version is easier than porting the whole 10,000 lines over. Just ask COBOL programmers what they're up to right now - it's not porting to a modern environment, it's maintaining the old one.
The other major issue is that Python 3 really didn't fix the major issues with Python that persist to this day. Atrocious byte code performance, a really awful deployment story, and perennial favorite: the GIL. Had just one of these been tackled in Python 3, the migration probably would've happened a lot faster. You might not care about those problems or they may not be problems for you, but they are for some of us and they persist to this day.
I will concede that on the whole, Python 3 is a better Python. But it's not 2x or 3x better. It's 10-20% better, and that's a tough sell to a busy engineer who has better things to do. I can't justify spending time on anything that is a mere 10% improvement when I have a pile of 2x improvements to work on.