Python version checked too late

[LawrenceEsswood]

Just tried to run cheribuild on an old machine. We check the python version in pycheribuild/utils.py, but this is included rather late in ./pycheribuild/main.py, which includes the config loader first which will give obscure asserts on old versions of python. A comment in main.py reveals that this include order is important? Shall I pull up the version check out of utils.py into main?

[jrtc27]

If you hoist it above imports then you'll make flake8 unhappy and need a whole load of E402 waivers... not particularly appealing to me. To be honest the whole concept is a bit futile, unless you do it as literally the first thing in every top-level Python script you have no clue what could run before your version check and thus be using unsupported language features. I think it's fine to just blow up if you use an ancient Python version.

[LawrenceEsswood]

I mean, 3.5 is hardly ancient. Is a guaranteed error message for unsupported python really something we don't care to have?

[LawrenceEsswood]

Also: why must we live under the tyranny of format checkers! No machine can tell me what to do!

[jrtc27]

Python 3.5 was released in 2015.

[LawrenceEsswood]

And is the version you get on Ubuntu 16.04, which is EOL in 2026, and so still perfectly reasonable that people may be using it.

[LawrenceEsswood]

We could always put the version check in the file that seems to assert when used with old versions of python. Seems sensible, as it does require it.

[jrtc27]

You have to pay for it, or get it for free as an individual with up to 3 machines for personal use. It's out of standard support. Using it in 2022 is not reasonable, you won't be getting security updates unless you really try.

[jrtc27]

(and the README clearly states that Ubuntu 18.04/20.04 are the supported versions)

[jrtc27]

I don't want version checks everywhere that uses f-strings or other features not in Python 3.5. That leads to insanity.

[LawrenceEsswood]

Which is why we should just put the check in the top-level file. And flake can go @*!& itself.

[jrtc27]

You can do that but that's not __main__.py, that's the files that include pycheribuild, of which there are 7 (look for the sys.path.insert/append).

And such comments about flake8 are not constructive.

[LawrenceEsswood]

Poor flake8 =(. Sorry, I will have a look at where you suggest.