fix(py/genkit): resolve all ty type errors and ensure all functions have proper types

[yesudeep]

Fix all type checking issues identified by ty in test files:

• Add MockerFixture import for pytest-mock's mocker fixture
• Add assertions before calling functions expecting non-None values
  (e.g., assert resp.message is not None before text_from_message)
• Change mock fixture return types to Any when tests create mock
  objects with mocked methods that break type contracts
• Add cast() calls for nested dictionary accesses where types can't
  be inferred
• Fix function signatures where return types didn't match returned
  values (e.g., return input.value or 0 for int return type)
• Rename veneer/resource_test.py to veneer_resource_test.py to fix
  pytest import collision with ai/resource_test.py
• Add noqa: ANN401 comments for intentional Any usage in fixtures
• Use ActionKind.CUSTOM enum instead of string literal 'custom'
• Fix BatchEvaluatorFn signature (async function returning list)
• Fix Flask context provider to use RequestData[Request]
• Fix HttpOptionsDict import in google-genai tests

Reduces ty errors from 414 to 0.

[gemini-code-assist]

Summary of Changes

Hello @yesudeep, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the type safety and maintainability of the Python Genkit codebase. It systematically addresses and resolves numerous type checking issues identified by ty, primarily by refining type annotations, replacing broad Any types with more specific ones, and ensuring consistent type contracts across various modules. The changes span core API definitions, internal utilities, and test files, aiming to improve code reliability and developer experience by providing clearer type information throughout the project.

Highlights

• Enhanced Type Safety: Replaced numerous instances of the generic Any type with more specific types like object or TypedDict across various function signatures, parameters, and return types, particularly within core Genkit AI API methods and internal utility functions. This significantly improves type checking and code predictability.
• Refined Type Hints in Core Modules: Updated type hints for configuration and metadata parameters in define_retriever, define_indexer, define_reranker, define_evaluator, define_batch_evaluator, define_model, define_embedder, define_prompt, and define_resource to use dict[str, object] or dict[str, SpanAttributeValue], providing clearer contracts for these functions.
• Improved Flow and Action Wrappers: Modified flow wrappers (async_wrapper, sync_wrapper) to explicitly cast return types and handle single input arguments, removing previous type: ignore[arg-type] comments. Introduced noqa: ANN401 comments for intentional Any usage in fixtures and specific utility functions to satisfy stricter type checking rules.
• Linting and Naming Convention Enforcement: Added ruff format to the bin/lint script for consistent code formatting and introduced a check to ensure Python test files adhere to the *_test.py naming convention, renaming py/packages/genkit/tests/genkit/ai/test_resource_integration.py to py/packages/genkit/tests/genkit/ai/resource_integration_test.py and similar files.
• Protocol and Casting for Immutability: Introduced _LatencyTrackable and _ModelCopyable protocols in genkit.core.action._action.py to handle latency tracking and model copying for immutable Pydantic models, ensuring type correctness when modifying objects.
• Generic ActionResponse: Made ActionResponse generic (ActionResponse[ResponseT]) to allow for more precise typing of the actual response data, enhancing type inference for action outputs.

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Ignored Files

• Ignored by pattern: .github/workflows/** (1)
  • .github/workflows/python.yml

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[gemini-code-assist]

Code Review

This is an excellent pull request that significantly improves the type safety of the Python codebase. The extensive changes to resolve ty type errors are thorough and well-executed. Replacing Any with more specific types like object, TypedDict, and generics, which significantly enhances code clarity and maintainability. The refactoring of some logic to be more robust and type-safe is also a welcome improvement. The consistency across the codebase is also commendable. Great job!

[yesudeep]

/gemini review

[gemini-code-assist]

Code Review

This pull request does an excellent job of resolving a large number of type errors throughout the Python codebase. The changes significantly improve type safety and code robustness. I appreciate the thoroughness, especially the move from Any to more specific types like object or TypedDict, the addition of return types, and the refactoring of logic to be more type-safe. The introduction of asyncio.Queue for streaming in flows.py is a great fix for a potential bug.

I have found one important issue in Action.stream that could lead to incorrect behavior for consumers of streaming flows, and one suggestion to improve JSON serialization in flows.py.

Overall, this is a high-quality contribution that greatly improves the maintainability of the Python code.