Creating multivariate polynomial rings change singular's global state

[roed314]

The following seems bad. It was revealed by the change in doctest framework at #12415. That ticket introduces a workaround (just resetting opt['red_tail'] to True).

sage: from sage.libs.singular.option import opt
sage: opt['red_tail']
True
sage: Rlocal.<x,y,z> = PolynomialRing(QQ, order='ds')
sage: opt['red_tail']
False

CC: @jpflori @sagetrac-jakobkroeker

Component: commutative algebra

Issue created by migration from https://trac.sagemath.org/ticket/13059

[roed314]

comment:1

J.groebner_basis(mult_bound=100) also resets opt['red_tail'], but J.groebner_basis() doesn't.