MAINT: add missing noexcept clauses (1/2)

After cython/cython#6087 it's much easier to
figure out the missing noexcept clauses. Indeed, cython up to 3.0.9 has
a warning that gives lots of false positives, but with the PR above
(already merged in cython master and backported to 3.0.x) all the
warnings are indeed cases of missing noexcept

To test use this file `test_cimport.pyx`:
```
# cython: language_level=3
cimport numpy
cimport numpy.random
cimport numpy.random._bounded_integers
cimport numpy.random._common
cimport numpy.random.bit_generator
cimport numpy.random.c_distributions
```
and build with `cython -X legacy_implicit_noexcept=True test_cimport.pyx`

This commit applies cleanly to the 1.26.x branch and is meant to
backport. The next commit fixes the remaining instances.

numpy/__init__.cython-30.pxd

@@ -242,7 +242,7 @@ cdef extern from "numpy/arrayobject.h":
         # Instead, we use properties that map to the corresponding C-API functions.
 
         @property
-        cdef inline PyObject* base(self) nogil:
+        cdef inline PyObject* base(self) noexcept nogil:
             """Returns a borrowed reference to the object owning the data/memory.
             """
             return PyArray_BASE(self)
@@ -254,34 +254,34 @@ cdef extern from "numpy/arrayobject.h":
             return <dtype>PyArray_DESCR(self)
 
         @property
-        cdef inline int ndim(self) nogil:
+        cdef inline int ndim(self) noexcept nogil:
             """Returns the number of dimensions in the array.
             """
             return PyArray_NDIM(self)
 
         @property
-        cdef inline npy_intp *shape(self) nogil:
+        cdef inline npy_intp *shape(self) noexcept nogil:
             """Returns a pointer to the dimensions/shape of the array.
             The number of elements matches the number of dimensions of the array (ndim).
             Can return NULL for 0-dimensional arrays.
             """
             return PyArray_DIMS(self)
 
         @property
-        cdef inline npy_intp *strides(self) nogil:
+        cdef inline npy_intp *strides(self) noexcept nogil:
             """Returns a pointer to the strides of the array.
             The number of elements matches the number of dimensions of the array (ndim).
             """
             return PyArray_STRIDES(self)
 
         @property
-        cdef inline npy_intp size(self) nogil:
+        cdef inline npy_intp size(self) noexcept nogil:
             """Returns the total size (in number of elements) of the array.
             """
             return PyArray_SIZE(self)
 
         @property
-        cdef inline char* data(self) nogil:
+        cdef inline char* data(self) noexcept nogil:
             """The pointer to the data buffer as a char*.
             This is provided for legacy reasons to avoid direct struct field access.
             For new code that needs this access, you probably want to cast the result
@@ -965,7 +965,7 @@ cdef extern from "numpy/ufuncobject.h":
 
     int _import_umath() except -1
 
-cdef inline void set_array_base(ndarray arr, object base):
+cdef inline void set_array_base(ndarray arr, object base) except *:
     Py_INCREF(base) # important to do this before stealing the reference below!
     PyArray_SetBaseObject(arr, base)
 
@@ -996,7 +996,7 @@ cdef inline int import_ufunc() except -1:
         raise ImportError("numpy.core.umath failed to import")
 
 
-cdef inline bint is_timedelta64_object(object obj):
+cdef inline bint is_timedelta64_object(object obj) noexcept:
     """
     Cython equivalent of `isinstance(obj, np.timedelta64)`
 
@@ -1011,7 +1011,7 @@ cdef inline bint is_timedelta64_object(object obj):
     return PyObject_TypeCheck(obj, &PyTimedeltaArrType_Type)
 
 
-cdef inline bint is_datetime64_object(object obj):
+cdef inline bint is_datetime64_object(object obj) noexcept:
     """
     Cython equivalent of `isinstance(obj, np.datetime64)`
 
@@ -1026,7 +1026,7 @@ cdef inline bint is_datetime64_object(object obj):
     return PyObject_TypeCheck(obj, &PyDatetimeArrType_Type)
 
 
-cdef inline npy_datetime get_datetime64_value(object obj) nogil:
+cdef inline npy_datetime get_datetime64_value(object obj) noexcept nogil:
     """
     returns the int64 value underlying scalar numpy datetime64 object
 
@@ -1036,14 +1036,14 @@ cdef inline npy_datetime get_datetime64_value(object obj) nogil:
     return (<PyDatetimeScalarObject*>obj).obval
 
 
-cdef inline npy_timedelta get_timedelta64_value(object obj) nogil:
+cdef inline npy_timedelta get_timedelta64_value(object obj) noexcept nogil:
     """
     returns the int64 value underlying scalar numpy timedelta64 object
     """
     return (<PyTimedeltaScalarObject*>obj).obval
 
 
-cdef inline NPY_DATETIMEUNIT get_datetime64_unit(object obj) nogil:
+cdef inline NPY_DATETIMEUNIT get_datetime64_unit(object obj) noexcept nogil:
     """
     returns the unit part of the dtype for a numpy datetime64 object.
     """

numpy/random/_bounded_integers.pxd.in

@@ -6,7 +6,7 @@ ctypedef np.npy_bool bool_t
 
 from numpy.random cimport bitgen_t
 
-cdef inline uint64_t _gen_mask(uint64_t max_val) nogil:
+cdef inline uint64_t _gen_mask(uint64_t max_val) noexcept nogil:
     """Mask generator for use in bounded random numbers"""
     # Smallest bit mask >= max
     cdef uint64_t mask = max_val