FastAPI 0.140.7 improves OpenAPI spec by avoiding dependency flattening

FastAPI, the lightning-fast Python web framework with over 101K GitHub stars, has released version 0.140.7. The headline change is a refactor to avoid flattening dependencies when generating OpenAPI schemas (PR #16076 by creator Sebastián Ramírez @tiangolo). Previously, the framework would flatten dependency structures during OpenAPI generation, which could produce redundant or less accurate schema representations. By removing this flattening, the new release ensures that the OpenAPI specification more faithfully reflects the actual dependency tree of your endpoints. This is particularly beneficial for complex applications with deeply nested dependencies, leading to cleaner API documentation and potentially fewer client-side errors.

In addition to the core refactor, the release includes internal upgrades: the latest-changes tool has been bumped to version 0.7.1, and a new CI job for OpenAPI dependency benchmarks has been added (PR #16075). These improvements help maintain FastAPI's performance and reliability as the framework continues to evolve. While not a major version, this update demonstrates FastAPI's commitment to precision and developer experience. Users can upgrade via pip install fastapi==0.140.7 to benefit from more accurate OpenAPI specs and faster documentation generation.