Add fastjet to conda-forge

[jmduarte]

Inspired by #91.

It would be great to get fastjet on conda-forge (especially in time for the first real release 3.4.0.0, which now appears to be imminent). I'm unsure if we want to make this a requirement for the release. What do others think?

@lgray @jpivarski @chrispap95 @henryiii

[lgray]

In my experience first you make a pypi release then you stick it into conda forge which follows pypi.
You can see from conda-forge/staged-recipes#15961 a while ago that going in with an RC or something that's a little wonky can be quite some pain.

[jpivarski]

Getting fastjet into conda-forge would be great!

As @lgray said, the conda-forge is a more frictionless process with non-RC releases. Only the first three digits of the version number (3.4.0) are constrained to match FastJet's; the fourth digit is free to increase as needed, so it is not necessary to get the conda-forge deployment right on the first non-RC attempt.

Also, the way that the conda-forge package gets populated is through the PyPI source wheel (e.g. fastjet-3.4.0.0.tar.gz). As long as the environment on conda-forge can take this tarball and compile all of its packages, it should work.

I'll also bring @chrisburr into this discussion, since he's a conda expert.

[jmduarte]

In progress by @lgray here: conda-forge/staged-recipes#21052

[jmduarte]

@lgray @chrispap95 perhaps the blocker from before (conda-forge/staged-recipes#21052 (comment)) is now resolved by #159 ?

[eduardo-rodrigues]

Adding a comment here so that I keep track of this for the inclusion of fastjet in the scikit-hep metapackage, see the discussions at scikit-hep/scikit-hep#173.

[eduardo-rodrigues]

This is in fact done since a while, see https://github.com/conda-forge/fastjet-feedstock.

[lgray]

Sorta - we got the recipe to work once for one version, and then the next version broke again. 🎉

[matthewfeickert]

Yeah, this should maybe be left open as a reminder that we still need to get the latest versions building and also make them multiplatform (still only Linux at this point).

[eduardo-rodrigues]

Indeed. Sorry for missing those facts.

[matthewfeickert]

Nothing to be sorry about! This is a good reminder that we need to follow up on getting conda-forge setup properly across multiplatforms.