Lots of test failures

Lots of test failures

Indeed. I do not know what happens. It looks like that the Cython compilation happened with language_level=2.

Many of the failures have nothing to do with cython, it's an actual bug in pplpy introduced in sagemath/pplpy@5fa3580

More precisely, in the Linear_Expression constructor with two arguments, there is a bool check for the first argument. If this evaluates to false (like it happens, for instance, with a=Cone([(0,0)])._lattice(0), then space_dimension is never set, which is what is causing most of the test failures.

Many of the failures have nothing to do with cython, it's an actual bug in pplpy introduced in sagemath/pplpy@5fa3580

More precisely, in the Linear_Expression constructor with two arguments, there is a bool check for the first argument. If this evaluates to false (like it happens, for instance, with a=Cone([(0,0)])._lattice(0), then space_dimension is never set, which is what is causing most of the test failures.

Indeed, bool([0, 0]) and bool(vector([0, 0])) behave differently! Thanks.

The failures in sage/geometry/lattice_polytope.py, sage/geometry/polyhedron/backend_ppl.py, sage/geometry/polyhedron/ppl_lattice_polytope.py and the first failure in sage/geometry/cone.py are caused by sagemath/pplpy@3ed9df4, but not by the change in Cython language level, but rather by the __mul__ change in the Variable class

The failures in sage/geometry/lattice_polytope.py, sage/geometry/polyhedron/backend_ppl.py, sage/geometry/polyhedron/ppl_lattice_polytope.py and the first failure in sage/geometry/cone.py are caused by sagemath/pplpy@3ed9df4, but not by the change in Cython language level, but rather by the __mul__ change in the Variable class

Hmm... this should have been catched by the pplpy doctest (https://github.com/sagemath/pplpy/blob/master/ppl/linear_algebra.pyx#L1192)

>>> from ppl import Variable
>>> from gmpy2 import mpz
>>> x = Variable(0)
>>> mpz(3) * x * mpz(5)

I indeed misinterpreted https://cython.readthedocs.io/en/latest/src/userguide/special_methods.html#arithmetic-methods (which affects __add__ but not __mul__).

I indeed misinterpreted https://cython.readthedocs.io/en/latest/src/userguide/special_methods.html#arithmetic-methods (which affects __add__ but not __mul__).

This was correctly interpreted, but works only with Cython>=3.0.0 which is not the default version in sage. This explains why doctests pass in conda.

Hopefully fixed in sagemath/pplpy#27

Can confirm that it fixes all issues in the downstream Arch sagemath package

Documentation preview for this PR (built with commit 525dedd; changes) is ready! 🎉