Package the GNU GMP (like scipy-openblas64)

[skirpichev]

Configure flags:

• --enable-fat
• --enable-shared & --disable-static
• --with-pic
• --disable-alloca

[skirpichev]

@casevh, @oscarbenjamin, I'm thinking to provide wheels for the GNU GMP.

See

python-gmp/scripts/cibw_before_all.sh

Lines 21 to 30 in c1a8665

	# config.guess uses microarchitecture and configfsf.guess doesn't
	# We replace config.guess with configfsf.guess to avoid microarchitecture
	# specific code in common code.
	rm config.guess && mv configfsf.guess config.guess && chmod +x config.guess
	./configure --enable-fat \
	--enable-shared \
	--disable-static \
	--with-pic \
	--disable-alloca \
	--prefix=$PREFIX -q

on how currently GMP built for the python-gmp package. I hope something like this should be acceptable for python-flint and gmpy2. I see few issues to address:

• --disable-alloca option. This is required for the python-gmp.
• mp_bitcnt_t.diff in gmpy2; it's not included in python-flint's patches and I'm not sure we should provide one (gmpy2/python-flint/python-gmp should work with system GMP library as well)

I'll add new project to the diofant org, unless you can suggest a better place.

Once done, we could also package MPFR and MPC.

[oscarbenjamin]

Another possible place could be the flintlib organisation.

In principle I like the idea of this but as I understand it there are various unresolved issues with this sort of thing.

Firstly would gmpy2, python-gmp and python-flint all need to pin exact versions of libgmp for ABI compatibility in the wheels? If they do pin exact versions does then what happens if someone needs different versions of python-flint and say gmpy2.

How do you record the dependency in the metadata correctly? Is it that the wheels on PyPI depend on libgmp but building from source can use a system GMP? What goes in requires or build-requires in pyproject.toml?

I think there is a bunch of discussion about these things here although I don't remember exactly what it says about this case:
https://pypackaging-native.github.io/

[skirpichev]

Firstly would gmpy2, python-gmp and python-flint all need to pin exact versions of libgmp for ABI compatibility in the wheels?

First, I don't think we can declare some dependencies on this package for python-gmp, etc. Though, such build dependency could be declared for similar packages for MPFR and MPC.

Like scipy-openblas* - you could install that package in CI (or locally) and then the python-gmp (or gmpy2) will use library from this package, instead of system's. Library files will be included in the python-gmp wheel by auditwheel and friends, just as now. So, rather nothing fancy.

The scipy-openblas* uses '.x.y' format for the package version. I think we can adopt something like that.