uv

3ece75fc - Error when `tool.uv.sources` is set in system-level configuration file (#12757)

Error when `tool.uv.sources` is set in system-level configuration file (#12757) ## Summary I think the lack of enforcement here is an oversight. We _do_ already enforce this for user-level configuration files (contrary to the issue -- at least, in my testing and from reading the code). Closes https://github.com/astral-sh/uv/issues/12753.