givaro + libsingular leads to segfault

[sagetrac-tmonteil]

When a finite field uses givaro as a backend, it is possible to deal with polynomial rings in a single variable, but dealing with multivariate polynomial ring (libsingular) leads to segfaults.

Here is an example:

sage: F = GF(3, impl='givaro')
sage: F
Finite Field of size 3
sage: type(F)                                                                                                                                                                                                
<class 'sage.rings.finite_rings.finite_field_givaro.FiniteField_givaro_with_category'>


sage: R.<a0> = PolynomialRing(F)
sage: type(R)
<class 'sage.rings.polynomial.polynomial_ring.PolynomialRing_dense_finite_field_with_category'>                                                                                                                                                                           
sage: F(R(2))
2

sage: R.<a0,a1> = PolynomialRing(F)
sage: type(R)
<class 'sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular'>
sage: F(R(2))
....
Segmentation fault

Not sure who to blame though.

From a report at Ask Sage question 53696: Crash with polynomial over Givaro finite field.

CC: @ClementPernet @roed314 @slel

Component: finite rings

Issue created by migration from https://trac.sagemath.org/ticket/30702

[mkoeppe]

comment:4

Moving to 9.4, as 9.3 has been released.