[Tech Debt] Avoid using reflection to load implementation classes of resources during the compilation phase

[da-daken]

Linked issue: #864

Purpose of change

Avoid using reflection to load implementation classes of resources during the compilation phase

Tests

ut test

API

no API

Documentation

• doc-needed
• doc-not-needed
• doc-included

[weiqingy]

Non-blocking:

The old check identified Python resources by whether clazz was a PythonResourceWrapper, while this now uses the presence of pythonClazz. Since PythonResourceProvider.provide() does not require pythonClazz when module is non-empty, do we want to document the assumption that descriptors reaching this classification path will always carry pythonClazz when they should be treated as Python?

[da-daken]

Thanks for your review! I think we should align on a single rule here. Since cross-language Python resources are required to declare pythonClazz, we probably should not leave other entry points open. Today, descriptors that take those alternate paths (e.g. non-empty module without pythonClazz) are classified as Java-side resources at plan-compilation time and fail at runtime. Tightening or closing those paths feels like a separate follow-up issue rather than something we need to solve in this PR—what do you think?

[weiqingy]

Agreed. Making pythonClazz the single rule and closing the alternate paths is cleaner than documenting the assumption, and it belongs in its own change. Nit: those descriptors classify as Java at compile time and only fail at runtime, so sharpening that into a clearer compile-time error would be a good tracker. Otherwise LGTM.

[wenjin272]

Given that normal Java AgentPlan paths don’t appear to produce module != empty && pythonClazz missing (module always be ""), I don’t think we need to preserve that old descriptor shape here. It seems limited to manually constructed 3-arg descriptors, so documenting/tightening that contract separately should be enough.

[da-daken]

@wenjin272 @weiqingy Thanks for your review! I’ve updated the submission. PTAL~