- no way to check if the lock file is up to date with the toml file

- no way to install packages from source if the version number is calculated (this will likely never be fixed as it's a design decision to use static package metadata insetad of setup.py, but is an incompatibility with pip)

- no way to have handle multiple environments: you get dependencies and dev-dependencies and that's it. You can fake it with extras, but it's a hack

- if you upgrade to a new python minor version you also have to upgrade to the latest poetry version or things just fail (Something to do with the correct selection of vendored dependencies. May have since been fixed -- new python versions don't come out all that often for me to run into it. And in fairness the latest pip is typically bundled with each python so it avoids that issue)

I still use poetry because it's more standard than hand-rolled pip freeze wrapper scripts, and there's definitely progress (the inability to sync packages was a hard requirement for me but is not fixed) but it's not quite there yet

I think it's because they have their own internal build systems, but they never play well with pip/conda et al.

One of my recent breakages was installing the recsim package, which pulled in tensorflow and broke my entire app. There's actually a recsim-no-tf package on PyPi, presumably because this happens to loads of people.

The core problem is that pip will happily overwrite your existing dependencies when you attempt to install a new package.