I have a .python-version file, and when I create a Python repo with github and specify that it should have a .gitignore, it adds the .python-version file to it. It seems to me that that file should NOT be ignored since other people running the code on different machines would want to know what version of Python they need.
So why is it .gitignored?
Old post but still relevant.
My answer would be "it depends".
The name of a virtual env can also be used in .python-version, if it is managed with the help of the virtualenv plugin of pyenv. This makes this file pretty useless it the project is managed on a public Git repo and you can exclude it (but not to do is harmless as told in other answers).
But (and I am in this situation) if you manage the project on a private repo and share virtual envs, it can make sense to not exclude it from Git. This allows you to work with a different environment (including the Python version) on an experimental branch of the project. Of course, it would have been far cleaner to fork or clone the original project and experiment with the new env in the copy, but sometimes it easier to just create a new branch.
At the end of the day, IMHO there is no universal answer to the question, and it depends on your workflow.
Should we gitignore the .python-version file?