According to PEP440 version specification 3.12 would mean 3.12.0 as version numbers are 0 padded.
But that's not the behaviour you get in UV, as uv will use any available patch version.

As the presence of a .python-version file means the user is managing the application environment via uv, I would suggest we replicate uv behaviour. So we should intend 3.12 as ==3.12.*.

When parsing .python-version should check if it's a valid version specifier ( https://packaging.python.org/en/latest/specifications/version-specifiers/#id5 ) and if none of the comparison operators is specified ( ~=, ==, !=, <=, >=, <, >) it should prefix it with ~= as it's the operator that matches default uv behaviour.

Thus a file like

3.12

would result in python.environment.requires = "~=3.12" leading to the same behaviour you would get locally with uv and any available version of python 3.12 being used.

Regarding the fact that in uv you can specify a python implementation, I don't think I have ever seen that used outside of very specific and highly vertical contexts where for example pypy is required. So for those we can probably just error and say that connect doesn't currently handle those. There wouldn't be a way to request pypy anyway in connect, so we aren't removing any feature.

Agreed with your conclusions @amol-, thanks much!