How to pass an env var to an un-owned build script?

[dk333333]

Hi,

When adding pyo3 as a dep to a rust_library, it runs its own build script. I would like to configure PYO3_PYTHON https://pyo3.rs/v0.20.3/building_and_distribution.html?highlight=interpreter#configuring-the-python-version.

Does rules_rust have a way to do this? For rust_library, I only see rustc_env. cargo_build_script does have build_script_env, but in this case I do not own the build script / did not make a cargo_build_script.

Also, using PYO3_PYTHON=... bazel run ... does not seem to propregate the env to the build script, is this supposed to be the case?

[illicitonion]

Assuming you're using crate_universe, you should be able to use https://bazelbuild.github.io/rules_rust/crate_universe.html#crate.annotation-build_script_env - https://github.com/bazelbuild/rules_rust/blob/main/examples/crate_universe/WORKSPACE.bazel has some examples of setting up (other) annotations when using crate_universe

[akesling]

I was just doing this myself. In my case, the environment variable needed to be set on the pyo3-ffi crate and so I added the following to my crates_repository in my WORKSPACE file:

crates_repository(
    ...
    annotations = {
        "pyo3-ffi": [crate.annotation(
            build_script_env = {
                "PYO3_CROSS_PYTHON_VERSION": "3.11",
            },
        )],
    },
    ...
)