evaluate_markers.bzl

# Copyright 2024 The Bazel Authors. All rights reserved.
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# Licensed under the Apache License, Version 2.0 (the "License");
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#     http://www.apache.org/licenses/LICENSE-2.0
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"""A simple function that evaluates markers using a python interpreter."""

load(":pep508_env.bzl", "env", _platform_from_str = "platform_from_str")
load(":pep508_evaluate.bzl", "evaluate")
load(":pep508_req.bzl", _req = "requirement")

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

    Args:
        requirements: dict[str, list[str]] of the requirement file lines to evaluate.

    Returns:
        dict of string lists with target platforms
    """
    ret = {}
    for req_string, platforms in requirements.items():
        req = _req(req_string)
        for platform in platforms:
            if evaluate(req.marker, env = env(_platform_from_str(platform, None))):
                ret.setdefault(req_string, []).append(platform)

    return ret