[Firebase AI] Add internal JSON Schema support in GenerationConfig

[andrewheard]

Added internal support for JSON Schema (response_json_schema) in GenerationConfig.

#no-changelog

[gemini-code-assist]

Code Review

This pull request adds internal support for response_json_schema in GenerationConfig. The changes include adding the new property, a corresponding internal initializer, and updating the Encodable conformance. The implementation is well-tested with new unit and integration tests that cover various schema types. The changes look good and the new feature is well-implemented. I've left one comment regarding code duplication in the integration tests which could be addressed to improve maintainability.

[gemini-code-assist]

Code Review

This pull request adds internal support for JSON Schema in GenerationConfig by introducing a responseJSONSchema property. The changes include a new internal initializer to handle this property and ensure it's mutually exclusive with the existing responseSchema.

The integration tests have been significantly refactored to be parameterized, allowing them to run against both OpenAPI schemas and the new JSON schemas. This is a great improvement for test coverage and maintainability.

My review includes suggestions to improve the custom Decodable implementation for the MailingAddress test helper. Specifically, I recommend decoupling it from the testing framework by throwing a DecodingError on ambiguous data instead of using test assertions directly within the initializer. This will make the decoding logic more robust and align with standard Swift practices.

[andrewheard]

/gemini review

[gemini-code-assist]

Code Review

This pull request adds internal support for JSON Schema in GenerationConfig, introducing a new responseJSONSchema property and a corresponding internal initializer. The changes are well-tested with new unit tests and a significant, well-executed refactoring of the integration tests to accommodate both OpenAPI and JSON schema formats. The test improvements, especially in SchemaTests.swift, enhance maintainability and clarity. I have one suggestion to reduce code duplication in the GenerationConfig initializers.

[paulb777]

Does this complete Step 1 of the workplan?

LGTM with double let warning addressed

[andrewheard]

Does this complete Step 1 of the workplan?

@paulb777 Yes, exactly, this is Step 1. (I also updated the plan to note that I did go ahead and drop the function calling schema part in this PR -- I still have the code stashed though)