Clean up the interim integration with Apple's Foundation Models
framework in Firebase AI Logic for Firebase 13.
Apple now natively supports third-party providers in the Foundation
Models framework via LanguageModel, which is implemented directly by
GeminiLanguageModel. The custom GenerativeModelSession,
SystemLanguageModel, HybridModel, custom GenerationSchema, and related
bridging types and protocols are now obsolete.
- Remove GenerativeModelSession, SystemLanguageModel, HybridModel,
GeminiModel, and related session protocols and provider types.
- Remove custom GenerationSchema, GeneratedContent, and related
structured output protocols.
- Remove internal responseJSONSchema support from GenerationConfig and
associated test permutations in FirebaseAILogic and TestApp.
- Remove IS_FOUNDATION_MODELS_SUPPORTED_PLATFORM build settings from
Package.swift and FirebaseAILogic.podspec.
BREAKING CHANGE: GenerativeModelSession, SystemLanguageModel,
HybridModel, GeminiModel, and associated interim integration types and
protocols have been removed. Use GeminiLanguageModel with Apple's
Foundation Models framework instead.
Implemented `GeminiLanguageModel`, providing an adapter for Google's
Gemini models conforming to Apple's `FoundationModels.LanguageModel`
protocol. This PR includes text to text generation capabilities; other
modalities and Gemini features will be handled in follow-up PRs.
**Note:** The `GeminiLanguageModel` implementation is guarded by the
environment variable `GEMINI_LANGUAGE_MODEL`. By default none of the
`GeminiLanguageModel` implementation is included.
Key additions:
- `GeminiLanguageModel`: Implements `LanguageModel` protocol with
reasoning capabilities, configuring execution via `ModelResource`
and `EndpointConfiguration`.
- `GeminiLanguageModelExecutor`: Converts prompt instructions and
history into Gemini streaming requests, yielding responses as
`LanguageModelSession.ResponseStream`.
- `GeminiTranscriptTranslator`: Translates Apple `Transcript` entries
and segments into Gemini `Content` structures while preserving thought
signatures and validating supported transcript features.
- `GeminiLanguageModel.Error` and `GeminiErrorMapper`: Translates Gemini
API, HTTP, and network errors into standard `LanguageModelError` cases
(`rateLimited`, `timeout`, `guardrailViolation`, `refusal`, and
`unsupportedLanguageOrLocale`) or `GeminiLanguageModel.Error` cases
(`serviceUnavailable`, `networkFailure`, `modelNotFound`, `apiError`).
The `APIError` payload is designed for seamless forward compatibility
with both GenerateContent and the upcoming Interactions API.
- Testing infrastructure: Adds `ConditionTrait.requireFoundationModels`
to conditionally run Foundation Models tests only on supported
platforms (macOS 27+, iOS 27+, watchOS 27+, visionOS 27+), along with
shared test constants, mock fixtures, and comprehensive unit and
integration test suites.
Andrew Heard