Comment by ckwalsh

Coming from a Meta background (not speaking on behalf of Meta):

"package/dependency management" - Everything is checked into a monorepo, and built with [Buck2](https://buck2.build/). There's tooling to import/update packages, but no need to reinvent pip or other package managers. Btw, Buck2 is pretty awesome and supports a ton of languages beyond python, but hasn't gotten a ton of traction outside of Meta.

"linting, formatting" - [Black](https://github.com/psf/black) and other public ecosystem tooling is great, no need to develop internally.

"why is type checking the exception" - Don't know about Astral, but for Meta / Google, most everyone else doesn't design for the scale of their monorepos. Meta moved from SVN to Git to Mercurial, then forked Mercurial into [Sapling](https://sapling-scm.com/) because simple operations were too slow for the number of files in their repo, and how frequently they receive diffs.

There are obvious safety benefits to type checking, but with how much Python code Meta has, mypy is not an option - it would take far too much time / memory to provide any value.