Backward-compatible feature expansion

Summary#

Problem#

New capabilities often need to ship into existing workflows without changing old behavior, but naive implementation can fork codepaths or silently alter defaults.

Solution#

Add the new capability behind explicit flags or optional parameters, keep defaults identical to previous behavior, and fold the implementation into existing codepaths only where the new conditions are present. This pattern appears in the SCAIL-2 support and 10-bit video support PRs.

Failure Modes#

Changing default behavior for existing users
Duplicating near-identical codepaths instead of conditionally extending one path
Adding new metadata or options without propagating them end-to-end

Sources#

https://github.com/Comfy-Org/ComfyUI/pull/14466
https://github.com/Comfy-Org/ComfyUI/pull/14373
https://github.com/Comfy-Org/ComfyUI/pull/14438
https://github.com/Comfy-Org/ComfyUI/pull/14402
https://github.com/Comfy-Org/ComfyUI/pull/14452
https://github.com/Comfy-Org/ComfyUI/pull/14306
https://github.com/Comfy-Org/ComfyUI/pull/14437
https://github.com/GitHubDaily/GitHubDaily/pull/267
https://github.com/GitHubDaily/GitHubDaily/pull/52
https://github.com/fastapi/full-stack-fastapi-template/pull/2330
https://github.com/fastapi/full-stack-fastapi-template/pull/2323
https://github.com/fastapi/full-stack-fastapi-template/pull/2266
https://github.com/fastapi/full-stack-fastapi-template/pull/2278
https://github.com/fastapi/full-stack-fastapi-template/pull/2248
https://github.com/fastapi/full-stack-fastapi-template/pull/2245
https://github.com/fastapi/full-stack-fastapi-template/pull/2265
https://github.com/fastapi/full-stack-fastapi-template/pull/2322
https://github.com/fastapi/full-stack-fastapi-template/pull/2326
https://github.com/react/react/pull/10000
https://github.com/react/react/pull/36759
https://github.com/react/react/pull/36753
https://github.com/react/react/pull/36754
https://github.com/react/react/pull/36755
https://github.com/react/react/pull/36752
https://github.com/thedaviddias/Front-End-Checklist/pull/664
https://github.com/thedaviddias/Front-End-Checklist/pull/680
mined_at: 2026-06-14T14:52:48Z

Sagwan Revalidation 2026-06-14T15:30:23Z#

verdict: ok
note: 하위호환 확장 원칙은 여전히 현대 개발 관행과 맞고 재사용 가능함