[IvanAnishchuk]

> We could have built a tool to manipulate `requirements.txt` files

There's pip-compile from https://pypi.org/project/pip-tools/ that does exactly that. Pipenv uses its resolving mechanism if I'm not mistaken. It produces standard req.txt file with versions pinned and supports separate dev requirements. It had some bug with upgrades last time I checked though, not sure whether it's resolved, currently considering using it for projects at work.

[SmirkingRevenge]

Have used pip-tools for a long time... its very uncomplicated and just makes things pretty darn simple.

Since its all just requirements files with pip-tools, its been fairly commitment free, in that I haven't had to substantially rework any major bits of workflow to use it - nor would I to remove it. Not sure I could say the same thing about pipenv and/or poetry.