sage.rings.number_field: Deprecate is_NumberFieldOrder

src/sage/rings/number_field/number_field.py

@@ -81,7 +81,7 @@
 
 
 import sage.libs.ntl.all as ntl
-
+import sage.rings.abc
 import sage.rings.complex_mpfr
 from sage.rings.polynomial.polynomial_element import Polynomial
 import sage.rings.real_mpfr
@@ -8444,10 +8444,9 @@ def _coerce_map_from_(self, R):
         """
         if R is int:
             return self._generic_coerce_map(R)
-        elif R in (ZZ, QQ, self.base()):
+        if R in (ZZ, QQ, self.base()):
             return self._generic_coerce_map(R)
-        from sage.rings.number_field.order import is_NumberFieldOrder
-        if is_NumberFieldOrder(R) and self.has_coerce_map_from(R.number_field()):
+        if isinstance(R, sage.rings.abc.Order) and self.has_coerce_map_from(R.number_field()):
             return self._generic_coerce_map(R)
         # R is not QQ by the above tests
         if isinstance(R, number_field_base.NumberField) and R.coerce_embedding() is not None:

src/sage/rings/number_field/number_field_element.pyx

@@ -50,6 +50,7 @@ from sage.libs.gmp.pylong cimport mpz_pythonhash
 from cpython.object cimport Py_EQ, Py_NE, Py_LT, Py_GT, Py_LE, Py_GE
 from sage.structure.richcmp cimport rich_to_bool
 
+import sage.rings.abc
 import sage.rings.polynomial.polynomial_element
 from sage.rings.polynomial.evaluation_ntl cimport ZZX_evaluation_mpfi
 import sage.rings.rational_field
@@ -1988,8 +1989,7 @@ cdef class NumberFieldElement(NumberFieldElement_base):
             raise ArithmeticError("factorization of 0 is not defined")
 
         K = self.parent()
-        from sage.rings.number_field.order import is_NumberFieldOrder
-        if is_NumberFieldOrder(K):
+        if isinstance(K, sage.rings.abc.Order):
             K = K.number_field()
         fac = K.ideal(self).factor()
         # Check whether all prime ideals in `fac` are principal
@@ -2088,8 +2088,7 @@ cdef class NumberFieldElement(NumberFieldElement_base):
         if R.is_field():
             return R.one()
 
-        from sage.rings.number_field.order import is_NumberFieldOrder
-        if not is_NumberFieldOrder(R):
+        if not isinstance(R, sage.rings.abc.Order):
             raise NotImplementedError("gcd() for %r is not implemented" % R)
 
         K = R.number_field()

src/sage/rings/number_field/number_field_rel.py

@@ -80,6 +80,7 @@
 from sage.categories.map import is_Map
 from sage.structure.sequence import Sequence
 
+import sage.rings.abc
 import sage.structure.parent_gens
 
 from . import maps
@@ -98,7 +99,7 @@
     put_natural_embedding_first, proof_flag,
     is_NumberFieldHomsetCodomain)
 from sage.rings.number_field.number_field_base import NumberField as NumberField_base
-from sage.rings.number_field.order import (RelativeOrder, is_NumberFieldOrder,
+from sage.rings.number_field.order import (RelativeOrder,
                                            relative_order_from_ring_generators)
 from sage.rings.number_field.morphism import RelativeNumberFieldHomomorphism_from_abs
 from sage.libs.pari.all import pari_gen
@@ -1013,9 +1014,9 @@ def _coerce_map_from_(self, R):
         """
         if R is int:
             return self._generic_coerce_map(R)
-        elif R in (ZZ, QQ, self.base_field()):
+        if R in (ZZ, QQ, self.base_field()):
             return self._generic_coerce_map(R)
-        if is_NumberFieldOrder(R) and R.number_field() is self:
+        if isinstance(R, sage.rings.abc.Order) and R.number_field() is self:
             return self._generic_coerce_map(R)
         mor = self.base_field()._internal_coerce_map_from(R)
         if mor is not None:

src/sage/rings/number_field/order.py

@@ -362,7 +362,11 @@ def is_NumberFieldOrder(R):
 
         sage: from sage.rings.number_field.order import is_NumberFieldOrder
         sage: x = polygen(ZZ, 'x')
-        sage: is_NumberFieldOrder(NumberField(x^2 + 1,'a').maximal_order())
+        sage: is_NumberFieldOrder(NumberField(x^2 + 1, 'a').maximal_order())
+        doctest:warning...
+        DeprecationWarning: The function is_NumberFieldOrder is deprecated;
+        use 'isinstance(..., sage.rings.abc.Order) or ... == ZZ' instead.
+        See https://github.com/sagemath/sage/issues/38124 for details.
         True
         sage: is_NumberFieldOrder(ZZ)
         True
@@ -371,6 +375,10 @@ def is_NumberFieldOrder(R):
         sage: is_NumberFieldOrder(45)
         False
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38124,
+                "The function is_NumberFieldOrder is deprecated; "
+                "use 'isinstance(..., sage.rings.abc.Order) or ... == ZZ' instead.")
     return isinstance(R, Order) or R == ZZ
 
 
@@ -2842,7 +2850,7 @@ def absolute_order_from_module_generators(gens,
         raise ValueError("each generator must be integral")
 
     K = gens.universe()
-    if is_NumberFieldOrder(K):
+    if isinstance(K, Order) or K == ZZ:
         K = K.number_field()
     V, from_V, to_V = K.vector_space()
     mod_gens = [to_V(x) for x in gens]