🐞 bug report

When a module uses isolate = True on the @rules_python//python/extensions:pip.bzl extension, Bazel evaluates the extension twice: once in a shared (non-isolated) scope that sees all modules tags, and once in an isolated scope that only sees the isolating module's tags. Crucially, the isolated evaluation cannot see rules_python's own pip.default tags, which are what populate the platforms dict in build_config().

That platforms dict is import for the entire wheel resolution pipeline. If it's empty, none of the pip packages actually end up populating the isolated hub repo.

I'm attaching a draft PR with a reproduction test and proposed fix.