evaluate_markers.bzl

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# Licensed under the Apache License, Version 2.0 (the "License");
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"""A simple function that evaluates markers using a python interpreter."""

load(":pep508_evaluate.bzl", "evaluate")
load(":pep508_requirement.bzl", "requirement")

def evaluate_markers(*, requirements, platforms):
    """Return the list of supported platforms per requirements line.

    Args:
        requirements: {type}`dict[str, list[str]]` of the requirement file lines to evaluate.
        platforms: {type}`dict[str, dict[str, str]]` The environments that we for each requirement
            file to evaluate. The keys between the platforms and requirements should be shared.

    Returns:
        dict of string lists with target platforms
    """
    ret = {}
    for req_string, platform_strings in requirements.items():
        req = requirement(req_string)
        for platform_str in platform_strings:
            plat = platforms.get(platform_str)
            if not plat:
                fail("Please define platform: '{}'".format(platform_str))

            if evaluate(req.marker, env = plat.env):
                ret.setdefault(req_string, []).append(platform_str)

    return ret