fix(parse_file): handle EnumDeclaration and AnnotationDeclaration in get_classes_and_methods

[luyuzhe111]

Summary

parse_file.get_classes_and_methods only sets current_class when it encounters ClassDeclaration or InterfaceDeclaration. Top-level enums and annotations fall through, so when the AST traversal reaches a method nested inside an enum constant's anonymous body, current_class is None and the function raises:

ValueError: Unable to find out class for method <name>

This crashes same_classes_and_methods (and any caller of get_classes_and_methods) on otherwise-valid Java sources.

Repos affected

Three repos in AmazonScience/migration-bench-java-full deterministically hit this crash during reward evaluation (8/8 rollouts each in one training step):

• thomasmueller/tinyStats — top-level enum with abstract method overridden in each constant's anonymous body (the canonical reproducer).
• justauth/JustAuth — same shape, different method name (authorize).
• orphan-oss/ognl — same shape, different method name (getValue).

Fix

Add EnumDeclaration and AnnotationDeclaration to the dispatch in get_classes_and_methods, alongside two new module-level constants ENUM and ANNOTATION (mirroring the existing CLASS / INTERFACE pair):

elif isinstance(node, javalang.tree.EnumDeclaration):
    current_class = node.name
    nodes.append((ENUM, current_class))
elif isinstance(node, javalang.tree.AnnotationDeclaration):
    current_class = node.name
    nodes.append((ANNOTATION, current_class))

same_classes_and_methods compares the same file pre/post-migration, so the new tuple types align on both sides — no change required there.

Tests

Added two fixtures and two parametrized cases covering the new shapes:

• testdata/Status.java — top-level enum with constants overriding an abstract
  method (matches the tinyStats shape that triggered the original crash).
• testdata/Marker.java — top-level @interface with a method element.

The new cases are appended to the existing @parameterized.expand block on test_get_classes_and_methods and assert the expected tuple sequences:

• Status.java → (("enum", "Status"), ("method", ("describe", False)), ...)
• Marker.java → (("annotation", "Marker"),)

Local run: python -m unittest migration_bench.lang.java.eval.test_parse_file -v — 19/19 pass (5 pre-existing get_classes_and_methods cases + 2 new + 12 unrelated).

End-to-end validation

Beyond unit tests, validated using a vLLM-served Qwen3-Coder-30B as the migration agent:

• thomasmueller/tinyStats rollout: pre-fix the reward function raisedValueError: Unable to find out class for method describe and the rollout errored out. Post-fix, the same repo runs end-to-end and produces a numeric reward (reward=1.0, build + test equivalence both pass) — the agent's full migration was successfully scored for the first time.
• The other two enum/annotation repos (JustAuth, ognl) no longer crash; they now flow through the reward function normally and either succeed or fail on legitimate migration criteria.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[sheilaliuxl]

nit: They're sorted
Otherwise LGTM

[luyuzhe111]

@sheilaliuxl thanks! should be fixed now!