Dev dependencies and testonly packages

[m-pilia]

Hi! Currently rules_pycross with lock_import allows to import development groups (e.g. with the development_groups argument). Would it be possible to make it so that targets coming from an imported dev dependency group are testonly in Bazel?

For instance, let's pretend we have a uv lockfile generated from a pyproject.toml that looks like this

[project]
...
dependencies = ["prod_dep_1", "prod_dep_2"]

[dependency-groups]
dev = ["dev_dep"]

And then we import it with lock_import

lock_import.import_uv(
    lock_file = "//:uv.lock",
    project_file = "//:pyproject.toml",
    repo = "my_deps",
    development_groups = ["dev"],
    ...
)

This will generate Bazel targets like

@my_deps://prod_dep_1
@my_deps://prod_dep_2
@my_deps://dev_dep

Would be interesting if @my_deps://dev_dep was testonly so that it cannot be accidentally added as a dependency of a non-test target.

[jvolkman]

I think that could be optional behavior, but I wouldn't make it the default. And we'd need to consider transitive deps of packages marked testonly.

[m-pilia]

I think that could be optional behavior, but I wouldn't make it the default.

Yes, I agree it shouldn't be default, and not based on the name of the dependency group itself but rather on a separate optional argument to the rule. Would be interesting to just have a way to "opt-in".