I'm quite happy -- even in commercial development -- to not be able to download new things if the package source is down. But not being able to access my exist

I'm quite happy -- even in commercial development -- to not be able to download new things if the package source is down. But not being able to access my existing dependencies is a blocker: I must be able to redeploy my own stuff, and to make fixes that don't involve version bumps. It's unlikely that I'll need a new dependency at the exact moment that the source is down, but fairly likely that if the source is down then I'll want to build something. For personal projects I'll have stuff cached locally, and I don't mind so much if I need to wait for CI. For work stuff I need to be able to fetch my dependencies in CI. Also, hammering upstream with requests for every single build is both slow and also sort of rude.