👋 hey folks……I have a python project with requirements captured in

pyproject.toml

(in the poetry style — as that is what the repo was configured to use pre-pants). I would like to add a new package. How do I go about finding the correct version? I used to use

poetry add $PACKAGE

, but I can’t seem to find a similar goal (or subtarget) for pants. thank you (in advance)!

You can add a

python_requirement

target if you want to manage that new package through Pants, you’ll just have to make sure it belongs to the same resolve as the requirements that you’re pulling in through Poetry

But what would the command be to say add

requests

?

pants add requests

?

Ah, I don’t think such a command exists; you’d have to add a

python_requirement

target to your build file and then regenerate the PEX lockfile using

pants generate-lockfiles

@better-van-82973 ok, makes sense. I’ll give that a whirl

Note that in the second case, you would still have to run

pants generate-lockfiles

to ensure that your new dependency makes it into the lockfile

yeah, so it’ll be using poetry to figure out the version of the package, but I will continue to use the pants lockfile for the universe of depdencies

Well, there is no magic here in Poetry or any tool. You can provide some input to constrain the version range your code is compatible with, and then the lockfile contains one specific version in that range that is also compatible with everything else in the lockfile. If you specify no constraints at all to poetry then that is equivalent to putting an unconstrained input request in your pyproject.toml

@breezy-twilight-65275 but the

poetry add requests

will determine a version that works, or maybe it just uses the latest version. So if it’s the later case, then I guess yeah, just always hand edit until you find a version that works

Indeed, Poetry just uses the latest version and then pins the range via caret requirement: https://python-poetry.org/docs/dependency-specification/#caret-requirements It looks like Poetry’s docs suggest that it will try to find a compatible version: https://python-poetry.org/docs/cli/#add

TIL 😄 thanks folks!

To clarify - Pants generating a lockfile is what finds a version that works. You don’t need to do that by hand editing. You can put an unconstrained

requests

in the inputs to that lockfile (e.g. in pyproject.toml), and you shouldn’t need to do any manual trial and error. However you may sometimes want to manually constraint that input, to prevent the lockfile selecting a version that doesn’t have a feature you need.

@happy-kitchen-89482 oh….can you show me what it would look like to have an unconstrained version of requests in pyproject.toml? I’ve never seen that before

Isn’t it something like

requests = "*"

? I’m no poetry expert though, maybe that doesn’t work for some reason