How to add Standard Library packages for in-build runtime

[mtanida]

Hi!

We are using Bazel 7.3.1 (though we are not yet using Bzlmod). We have been using rules_python for some time now, including py_runtime for our in-build Python3.

Things are working fine in local builds, but we have recently started to introduce remote-execution (via Buildbarn) and some of our Python targets are failing. Specifically, we have some gen_rule targets that invoke py_binary targets to generate outputs, such as source files and headers. These targets are failing because they attempt to import Python standard library packages, and those packages are not being included in the remote execution environment.

I'm not exactly sure what the correct solution is. I have attempted to add the contents of the lib folder like so:

py_runtime(
    name = "python_runtime",
    files = glob([
       "lib/**/*.py",
       "lib/**/*.so*",
    ]),
    interpreter = "bin/python3",
    python_version = "PY3",
)

This seems to include the contents of the lib folder into the runfiles, but it also seems to be erroneously adding __init__.py files into every directory for some reason.

Perhaps I'm approaching this wrong? Do others have experience with using py_runtime with remote execution? Any help would be greatly appreciated!!!!!!

[mtanida]

OK - so using --incompatible_default_to_explicit_init_py helped! I had no idea that was a thing.