Make kiwisolver an optional dependency?

[dstansby]

#9082 introduced a nice new geometry manager, but now installing Matplotlib requires installing kiwisolver. Would it be possible to make this an optional dependency that is only needed for doing constrained layout stuff (especially since the layout stuff is experimental at the moment)?

[jklymak]

Is kiwisolver being a difficult install?

[dstansby]

On my machine at least it doesn't seem to come pre-compiled so builds it from a source distribution, which takes ~30 secs. It's not a massive issue, but keeping the install simple with minimum dependencies would be nice.

[jklymak]

@tacaswell and @QuLogic discussed on gitter, and should be the final arbitrers. I have no idea how onerous this dependency is in the general install world, but it would be a shame from a usability point of view if it wasn't installed by default. e.g. its a lot easier to tell a user to try constrained_layout=True then to get them to pip intstall kiwisolver, etc etc after they have already installed matplotlib.

[anntzer]

Looks like @matthew-brett is trying to get OSX wheels built for that? (nucleic/kiwi#44)
FWIW it is really easy to build a manylinux wheel (once you have a standard manylinux docker setup).

[story645]

@jklymak it's also required for the tests...which are there own odd install set.

[matthew-brett]

@anntzer - yes I'm using multibuild which builds both OSX and manyinux wheels, as well as Windows wheels:

https://github.com/MacPython/kiwisolver-wheels

The sticking point is the issue you've pointed to.

[anntzer]

what's wrong with running pytest from their source folder? (yes, you may prefer being sure not to be accidentally importing something from the source tree, but it's a C-only package with no python component so indeed you won't be importing anything from the source tree (other than the tests))

[story645]

I am running pytest from the source folder!

[anntzer]

I meant the kiwi tests (the issue mentioned by @matthew-brett in the kiwi repo).

[matthew-brett]

@anntzer - yes, that's not a bad idea in our case (where we do have the source repo to hand) - I'll give it a go.

[QuLogic]

kiwisolver is in Fedora now.

[jklymak]

Thanks a lot @QuLogic

[matthew-brett]

The Kiwisolver maintainer @MatthieuDartiailh has kindly put up wheels now:

https://pypi.org/project/kiwisolver/#files

@MatthieuDartiailh - I guess you're planning to keep updating these for new releases? I'm asking because it may well affect whether Matplotlib takes Kiwisolver as a dependency.

[MatthieuDartiailh]

Yes I will keep updating those. Even though I have no short term plans for updates to this library. However should any bugs be found, I will try to address those and release in consequence.

[dstansby]

I'm happy leaving this as a dependency in that case - thanks a lot @MatthieuDartiailh for making the wheels!

[MatthieuDartiailh]

You should rather thank @matthew-brett for setting up the whole infrastructure. Even the upload of the wheels is automated.

[jamesshannon]

FWIW kiwisolver takes a non-trivial amount of time (maybe 5 minutes) to compile & install on my power- and resource- constrained raspberry Pi.

[matthew-brett]

I believe there are wheels, for Python 3.5 : https://www.piwheels.hostedpi.com/simple/kiwisolver/