What's your use case for UV_NO_SYNC? I assume the option exists for a reason, but aside from maybe a modest performance improvement when working with a massive complex package environment, I'm not sure what problem it solves.
some packages that I use for development need to be part of the virtual env. for example ipdb.
so i do uv pip install ipdb.
but then, after uv add somepackage
uv sync happens and cleans up all extras. to keep extras, you need to run uv sync --inexact. But there is no env var for `--inexact`, so I end up doing the sync manually.