I am a slow adopter of uv. I'll be honest, its speed has never been a big deal to me and, in general, it is YAPT (yet another package tool), but this one feature may make me reconsider. Pinning versions is less than perfect but I would really like to be able to stay XXX days behind exactly for this reason.
I think the python community, and really all package managers, need to promote standard cache servers as first class citizens as a broader solution to supply chain issues. What I want is a server that presents pypi with safeguards I choose. For instance, add packages to the local index that are no less than xxx days old (this uv feature), but also freeze that unless an update is requested or required by a security concern, scan security blacklists to remove/block packages and versions that have been found to have issues. Update the cache to allow a specific version bump. That kind of thing. Basically, I have several projects and I just want to do a pip install but against my own curated pypi. I know this is the intent of virtual envs/lock files, etc, but coordinating across projects and having my own server to grab from when builds happen (guaranteeing builds won't fail) is import. At a minimum it would be good to have a 'curated.json' or something similar that I could point pip/other package managers to to enforce package policies across projects. These supply chain attacks show that all it takes is a single update and your are in big trouble so we, unfortunately, need more layers of defense.