PEP 723: use a new `[run]` table instead of `[project]`?

[brettcannon]

@brettcannon

For example, a tool could say, “the specified file requires Python >=3.8, but only Python 3.7 was found. Please install an appropriate version of Python.” which is clearer than TypeError: 'type' object is not subscriptable (which is something I ran into trying to backport some code in packaging to Python 3.7).

I think the whole requires-python question comes down to whether we want to be writing down what’s required to make an single-file script/application run, or is this just a list of requirements that must somehow be installed? If it’s the former than the version of Python that the code requires is part of the information to run the script (and I think the only thing necessary that I can think of beyond its dependencies). But if it’s the latter case of just requirements then the Python version requirement is obviously superfluous. The importance of this probably plays into whether you think such scripts should be as shareable as possible across machines as that’s where specifying the required Python version plays into this.