Fix typo, fix the crucial part (yeah I forgot...) and keep a silly de…

…bug print around...

numpy/core/src/umath/dispatching.c

@@ -53,6 +53,9 @@
 #include "ufunc_type_resolution.h"
 
 
+#define PROMOTION_DEBUG_TRACING 0
+
+
 /* forward declaration */
 static NPY_INLINE PyObject *
 promote_and_get_info_and_ufuncimpl(PyUFuncObject *ufunc,
@@ -185,6 +188,17 @@ resolve_implementation_info(PyUFuncObject *ufunc,
     PyObject *best_dtypes = NULL;
     PyObject *best_resolver_info = NULL;
 
+#if PROMOTION_DEBUG_TRACING
+    printf("Promoting for '%s' promoters only: %d\n",
+            ufunc->name ? ufunc->name : "<unknown>", (int)only_promoters);
+    printf("    DTypes: ");
+    PyObject *tmp = PyArray_TupleFromItems(ufunc->nargs, op_dtypes, 1);
+    PyObject_Print(tmp, stdout, 0);
+    Py_DECREF(tmp);
+    printf("\n");
+    Py_DECREF(tmp);
+#endif
+
     for (Py_ssize_t res_idx = 0; res_idx < size; res_idx++) {
         /* Test all resolvers  */
         PyObject *resolver_info = PySequence_Fast_GET_ITEM(
@@ -774,7 +788,7 @@ promote_and_get_info_and_ufuncimpl(PyUFuncObject *ufunc,
  *        either by the `signature` or by an `operand`.
  *        (outputs and the second input can be NULL for reductions).
  *        NOTE: In some cases, the promotion machinery may currently modify
- *        these.
+ *        these including clearing the output.
  * @param force_legacy_promotion If set, we have to use the old type resolution
  *        to implement value-based promotion/casting.
  */
@@ -802,7 +816,7 @@ promote_and_get_ufuncimpl(PyUFuncObject *ufunc,
             Py_XSETREF(op_dtypes[i], signature[i]);
             assert(i >= ufunc->nin || !NPY_DT_is_abstract(signature[i]));
         }
-        else if (i > nin) {
+        else if (i >= nin) {
             /*
              * We currently just ignore outputs if not in signature, this will
              * always give the/a correct result (limits registering specialized

numpy/core/src/umath/ufunc_object.c

@@ -2738,29 +2738,15 @@ reducelike_promote_and_resolve(PyUFuncObject *ufunc,
         Py_INCREF(operation_DTypes[0]);
         operation_DTypes[2] = operation_DTypes[0];
         Py_INCREF(operation_DTypes[2]);
-        /*
-         * We have to force the dtype, because otherwise value based casting
-         * may ignore the request entirely.  This means that `out=` the same
-         * as `dtype=`, which should probably not be forced normally, so we
-         * only do it for legacy DTypes...
-         */
-        if (NPY_DT_is_legacy(operation_DTypes[0])
-                && NPY_DT_is_legacy(operation_DTypes[1])) {
-            if (signature[0] == NULL) {
-                Py_INCREF(operation_DTypes[0]);
-                signature[0] = operation_DTypes[0];
-                Py_INCREF(operation_DTypes[0]);
-                signature[2] = operation_DTypes[0];
-            }
-        }
     }
 
     PyArrayMethodObject *ufuncimpl = promote_and_get_ufuncimpl(ufunc,
             ops, signature, operation_DTypes, NPY_FALSE, NPY_FALSE);
-    Py_DECREF(operation_DTypes[1]);
+    /* Output can currently get cleared, others XDECREF in case of error */
+    Py_XDECREF(operation_DTypes[1]);
     if (out != NULL) {
-        Py_DECREF(operation_DTypes[0]);
-        Py_DECREF(operation_DTypes[2]);
+        Py_XDECREF(operation_DTypes[0]);
+        Py_XDECREF(operation_DTypes[2]);
     }
     if (ufuncimpl == NULL) {
         return NULL;

numpy/core/tests/test_ufunc.py

@@ -2126,6 +2126,12 @@ def test_logical_ufuncs_support_anything(self, ufunc):
         c = np.array([1., 2.])
         assert_array_equal(ufunc(a, c), ufunc([True, True], True))
         assert ufunc.reduce(a) == True
+        # check that the output has no effect:
+        out = np.zeros(2, dtype=np.int32)
+        expected = ufunc([True, True], True).astype(out.dtype)
+        assert_array_equal(ufunc(a, c, out=out), expected)
+        out = np.zeros((), dtype=np.int32)
+        assert ufunc.reduce(a, out=out) == True
 
     @pytest.mark.parametrize("ufunc",
              [np.logical_and, np.logical_or, np.logical_xor])