Update python_info aspect to accommodate Python targets that only have rules_python providers

[mnoah1]

As the Python rules are gradually phasing out use of the builtin PyInfo provider in favor of the ones from rules_python, there could be cases where a repository is on a Bazel version lower than 8, but the built in PyInfo is still missing from a given target.

In our repo's case, we are in the process of migrating to rules_py, which uses the rules_python providers only (aspect-build/rules_py#311), and not the built in ones.

This change adds support for rules_python providers in the aspect for Bazel versions less than 8:

• Bazel <8 - this adds an extra check rules_python in the repo's external rules. The load statement will only run if present, and when this is the case, the rules_python providers will be considered as a secondary option to the builtin ones.
• Bazel 8 - rules_python providers only [existing behavior]

[mnoah1]

It looks like all the e2e tests pass with this change, but I'm seeing a failure in the [analysis] Qodana android-forked-bazel-rules-project step with error: found 'project contains no modules' in the build log. I don't think it seems related to my change but I'm not quite sure - could you help me verify?

[mnoah1]

Hi @agluszak - could you give this one another look when you have a chance? Thanks.

[JetBrainsBazelBot]

Hi, we've added a new test - could you please merge main for it to pass?
regarding [analysis] Qodana android-forked-bazel-rules-project - we are investigating, but it seems your change indeed breaks something in one of our android project e2e test

[mnoah1]

could you please merge main for it to pass?

Updated - looks like the new one is passing.

regarding [analysis] Qodana android-forked-bazel-rules-project - we are investigating, but it seems your change indeed breaks something in one of our android project e2e test

Thanks - let me know if you find any more specifics (I was able to easily run the other e2e tests locally, but seems the Qodana ones require a token and are a bit harder for me to debug myself).

[JetBrainsBazelBot]

we'll get back to you monday on the qodana test

[gottagofaster236]

This is the log from the failing Android test. I'm not 100% sure why it's failing but the test project indeed does not have a dependency on rules_python

2025-02-07T12:42:51.793Z [13336] INFO - �[31m�[1mERROR: �[0mat /root/.cache/bazel/_bazel_idea/d1aa40fbc8d41d43ca12eb8239db2224/external/bazelbsp_aspect/aspects/core.bzl:3:6: at /root/.cache/bazel/_bazel_idea/d1aa40fbc8d41d43ca12eb8239db2224/external/bazelbsp_aspect/aspects/extensions.bzl:3:6: at /root/.cache/bazel/_bazel_idea/d1aa40fbc8d41d43ca12eb8239db2224/external/bazelbsp_aspect/aspects/rules/python/python_info.bzl:4:6: Unable to find package for @@rules_python//python:defs.bzl: The repository '@@rules_python' could not be resolved: Repository '@@rules_python' is not defined.

[mnoah1]

This is now updated to better handle possible scenarios, and all checks are now passing. This is ready for another look when you have a chance.

[mnoah1]

@agluszak @jastice @gottagofaster236 just wanted to follow up on this.

[xuansontrinh]

@mnoah1 the PR LGTM.
Could you please resolve the conflict with the readme file and then we can merge it?