Infinite recursion in LinearMatrixGroup_generic

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• I have searched the existing issues for a bug report that matches the one I want to file, without success.

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• I have read the documentation and troubleshoot guide

Environment

- **OS**: ubuntu
- **Sage Version**: 9.5

Steps To Reproduce

In some situation, the special linear groups sage.groups.matrix_gps.linear.LinearMatrixGroup_generic is such that the two methods order (inherited from sage/groups/group.pyx) and cardinality (inherited from sage/categories/finite_groups.py) are calling each other

q = 7
FqT.<T> = GF(q)[]
N = T^2+1
FqTN = QuotientRing(FqT, N*FqT)
S = SL(2,FqTN)
S.is_finite()

In particular it breaks S.is_finite() which should work out of the box given that the category of S is the category of finite groups (obtained by S.category()).

Expected Behavior

True

Actual Behavior

Traceback (most recent call last):
<ipython-input-11-397d936442b9> in <module>
----> 1 S.is_finite()

.../sage/groups/group.pyx in sage.groups.group.Group.is_finite (build/cythonized/sage/groups/group.c:3068)()
    188             NotImplementedError
    189         """
--> 190         return self.order() != infinity
    191 
    192     def is_multiplicative(self):

.../sage/groups/group.pyx in sage.groups.group.Group.order (build/cythonized/sage/groups/group.c:2924)()
    171         """
    172         try:
--> 173             return self.cardinality()
    174         except AttributeError:
    175             raise NotImplementedError

.../sage/categories/finite_groups.py in cardinality(self)
    106                 return self._cardinality_from_iterator()
    107             else:
--> 108                 return o()
    109 
    110         def some_elements(self):

... last 2 frames repeated, from the frame below ...

.../sage/groups/group.pyx in sage.groups.group.Group.order (build/cythonized/sage/groups/group.c:2924)()
    171         """
    172         try:
--> 173             return self.cardinality()
    174         except AttributeError:
    175             raise NotImplementedError

RecursionError: maximum recursion depth exceeded while calling a Python object

Additional Information

No response