[pchm]

OP here, thanks for clarifying this - I can imagine it's a super complex problem and I truly appreciate all the work that you (and other contributors) have put into this project.

My only point (and a source of confusion) here is that I never anticipated the cascading effect that installing a single package can have on seemingly unrelated parts of the system. I've been using homebrew for many years and as far as I remember, the only time anything broke like this was when I explicitly ran update/upgrade.

I'm going to try HOMEBREW_NO_INSTALL_UPGRADE/HOMEBREW_NO_AUTO_UPDATE — it does seem like a more intuitive default, but again, I don't know anything about how homebrew works under the hood.

Thanks again!

[RNCTX]

There's more than one way to skin a cat.

Personally, I have moved to downloading large things (Python, Postgres by your example) as standalone apps, and only use Homebrew for small libraries and CLI tools. I think that makes more sense.

You can download all of the Mac Python versions you want from python.org and you can get Postgres from postgresapp.com which provides a nice toolbar interface to start and shutdown servers of various versions.