Python 3 adoption at the time of writing this book

So, is Python 3, thanks to new exciting features, well adopted among its community? Sadly, not yet. The popular page Python 3 Wall of Superpowers (https://python3wos.appspot.com) that tracks the compatibility of most popular packages with the Python 3 branch was, until not so long ago, named Python 3 Wall of Shame. This situation is changing and the table of listed packages on the mentioned page is slowly turning "more green" with every month. Still, this does not mean that all teams building their applications will shortly use only Python 3. When all popular packages are available on Python 3, the popular excuse—the packages that we use are not ported yet—will no longer be valid.

The main reason for such a situation is that porting the existing application from Python 2 to Python 3 is always a challenge. There are tools like 2to3 that can perform automated code translation but they do not ensure that the result will be 100% correct. Also, such translated code may not perform as well as in its original form without manual adjustments. The moving of existing complex code bases to Python 3 might involve tremendous effort and cost that some organizations may not be able to afford. Still such costs can be split in time. Some good software architecture design methodologies, such as service-oriented architecture or microservices, can help to achieve this goal gradually. New project components (services or microservices) can be written using the new technology and existing ones can be ported one at a time.

In the long run, moving to Python 3 can only have beneficial effects on a project. According to PEP-404, there won't be a 2.8 release in the 2.x branch of Python anymore. Also, there may be a time in the future when all major projects such as Django, Flask, and numpy will drop any 2.x compatibility and will only be available on Python 3.

My personal opinion on this topic can be considered controversial. I think that the best incentive for the community would be to completely drop Python 2 support when creating new packages. This, of course, greatly limits the reach of such software but it may be the only way to change the way of thinking of those who insist on sticking to Python 2.x.