Question about pyproject.toml syntax

[adamjstewart]

The README for this project suggests using:

[build-system]
requires = ["jupyter_packaging~=0.10.0,<2"]
build-backend = "setuptools.build_meta"

However, doesn't ~=0.10.0 imply >=0.10.0,==0.10.*? So not only is the <2 unnecessary, it's also misleading since it suggests that version 0.11.0 or 1.X would work? I'm referring to this syntax specification.

[adamjstewart]

The reason I ask is that a lot of other packages like jupyterlab and jupyter-server are using jupyter_packaging~=0.9,<2 in their pyproject.toml.

[blink1073]

Hi @adamjstewart, good catch, mind submitting a PR to update the README?

[bollwyvl]

Thanks for all those!

I don't use (or encourage) ~ and ^ within the python/conda packaging space, though it seems unavoidable (if more principled) in the npm space (which has a much stricter version regex). My issues: the two operators have different meanings for different package managers/for different leading values 0.x vs 1.x/edge cases (alpha, etc) and don't actually save too many electrons vs concrete top and bottom pins. Indeed, as a project, we should be striving for things that work across major revision boundaries, eventually, if the upstreams are still supported... even if it takes a while to get there.