ENH: Adding __array_ufunc__ capability to MaskedArrays (again)

doc/release/upcoming_changes/22914.improvement.rst

@@ -0,0 +1,9 @@
+MaskedArray gains a ``__array_ufunc__`` method to better handle ufuncs
+----------------------------------------------------------------------
+The MaskedArray class now has an implementation of `__array_ufunc__` that
+handles deferrals to the desired implementations of the ufunc. If a masked
+implementation of a ufunc exists, that implementation will take priority.
+This means that code called with MaskedArray ma as ``np.ufunc(ma)`` will
+behave the same as ``np.ma.ufunc(ma)``. Additionally, adding this helps with
+dispatching to subclasses and preserving the proper types when another
+implementation should take priority.

numpy/core/src/common/binop_override.h

@@ -105,12 +105,6 @@ binop_should_defer(PyObject *self, PyObject *other, int inplace)
      * logic for forward binop implementations.
      */
 
-    /*
-     * NB: there's another copy of this code in
-     *    numpy.ma.core.MaskedArray._delegate_binop
-     * which should possibly be updated when this is.
-     */
-
     PyObject *attr;
     double self_prio, other_prio;
     int defer;

numpy/lib/tests/test_function_base.py

@@ -786,7 +786,7 @@ def test_subclass(self):
                      mask=[[False, False], [True, False],
                            [False, True], [True, True], [False, False]])
         out = diff(x)
-        assert_array_equal(out.data, [[1], [1], [1], [1], [1]])
+        assert_array_equal(out.data, [[1], [4], [6], [8], [1]])
         assert_array_equal(out.mask, [[False], [True],
                                       [True], [True], [False]])
         assert_(type(out) is type(x))