Consider python specific options via --pip-args

[atugushev]

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[atugushev]

This allows targeting specific Python versions:

$ echo click | pip-compile - -qo- --no-header --no-annotate
click==8.1.3

$ echo click | pip-compile - -qo- --no-header --no-annotate --pip-args='--python-version=3.0.0'
click==6.7

cc: @mitsuhiko

[chrysle]

Looks good, but this will need a test.

[chrysle]

@atugushev This would need merging for the feature worked on in #1998. Could you add a test?

[atugushev]

@chrysle I'm inclined to close this, as is may not work as expected.

[chrysle]

@atugushev Could you elaborate on that?

[georgek]

@atugushev would love to know more about what you don't think would work as expected. I was looking to build upon this to enable the correct default behaviour of pip-tools when installed by pipx or as a system package etc.

[chrysle]

@atugushev Gentle ping.

[atugushev]

My initial intent was to target a specific Python interpreter. I thought --python-version was the solution. However, it is only used for wheel and "Requires-Python" compatibility checks, as stated in the documentation:

$ pip install --help
...
  --python-version <python_version>
                              The Python interpreter version to use for wheel and "Requires-Python"
                              compatibility checks. Defaults to a version derived from the running
                              interpreter. The version can be specified using up to three dot-
                              separated integers (e.g. "3" for 3.0.0, "3.7" for 3.7.0, or "3.7.3").
                              A major-minor version can also be given as a string without dots (e.g.
                              "37" for 3.7.0).

I know there is a --python <python> option, however it runs pip in a subprocess which doesn't work well with the pip-tools resolver.

[georgek]

It sounds like this approach might be ruled out for the purposes of #1998 then. But just for my own curiosity and perhaps to help others look for this:

What difference is there in practice between targeting a specific interpreter vs specifying --python-version?

What is the problem with pip-tools and --python? Could pip-tools be changed to work better with this option?

[chrysle]

What is the problem with pip-tools and --python? Could pip-tools be changed to work better with this option?

I think @atugushev refers to the problem that we too heavily rely on pip's internals; it doesn't help us to pass the Python option to pip, as we create a command representation manually via the corresponding InstallCommand only to utilize it to parse and return the options to us, and then invoke the resolution process manually – which means our setting doesn't have any impact on the actual resolution result. In order to benefit from the option, we would instead need to run pip and parse its results, as done for pip-sync. There is an open issue for that (#1654) but actually decoupling would require huge changes; I can look into it, but won't promise anything, especially since activity here has been largely reduced by most maintainers and uv is likely to kick us totally out of business (no hard feelings).