I haven't used Ruby, but Python also was a huge pain and there were many attempts at fixing it, but all had some issues for me. That is until I found poetry2nix.
My understanding is that Python packages are directly installable via nix, at least some of them. This is a completely parallel way of installing packages from the regular way, which sucks, but at least it works in theory. I never personally tried it though.
Stack (Haskell) was awesome because it’s Nix aware, enabling it to create its own env to handle C deps on it’s own.
So I haven't used mach-nix, but from what I see it provides its own way of specifying dependencies. While in case of poetry2nix you are using poetry for dependency management and poetry2nix just translates it to Nix.
The biggest benefit for using poetry is the dependency resolver which is much smarter than in pip and actually finds packages that match the version requirements (although looks like mach-nix also has a smart resolver.
Other benefits are:
* nice CLI
* ability to package application and upload to PyPI
* poetry can still be used by people who don't use Nix
Regarding non-python dependencies, this is solved by overrides file[1]. That way most of the time you don't have to think about it. You can also override the override in your project as well.
