Implement version constraint operator "tilde" (like npm does)

I see more and more python packages with this kind of deps: pyramid >=1.4.5, <1.5.0. It makes a lot of sense for projects following SemVer, and this pattern looks like a hack.

NPM implemented it as this: ~1.2.3 := >=1.2.3-0 <1.3.0-0 (https://npmjs.org/doc/misc/semver.html)

This syntax would be interesting: pyramid ~= 1.4.5

[dstufft]

The ~= operator is part of PEP 440 and is now in the develop branch of pip.

[mockturtl]

I totally agree that the tilde operator is not well explicit. Maybe it’s a bad idea.

Consider the caret ^, instead / also. If you can assume SemVer, it’s better behaved:

• >=1.4.5, <1.5.0 is overconstrained: a 1.x release MUST NOT have breaking changes.
• ~1.4 allows 1.4.0 when you want a patch-level floor of 1.4.5.

prior art

nodejs (npm) dart (pub) ruby (gem) (see “compound requirement”)

(Apologies if this doesn’t belong here; this issue was my first search-engine result for “npm version constraint.” I believe it’s relevant, per my reading of PEP 440.)