Merge pull request #5676 from jaimefrio/ufunc_at_nout

BUG: ufunc.at only works on single output ufuncs

2 files changed, 9 insertions, 0 deletions

diff --git a/numpy/core/src/umath/ufunc_object.c b/numpy/core/src/umath/ufunc_object.c
index 9f2a7d57f..36201b3ea 100644
--- a/numpy/core/src/umath/ufunc_object.c
+++ b/numpy/core/src/umath/ufunc_object.c
@@ -5109,6 +5109,12 @@ ufunc_at(PyUFuncObject *ufunc, PyObject *args)
         return NULL;
     }
 
+    if (ufunc->nout != 1) {
+        PyErr_SetString(PyExc_ValueError,
+            "Only single output ufuncs supported at this time");
+        return NULL;
+    }
+
     if (!PyArg_ParseTuple(args, "OO|O", &op1, &idx, &op2)) {
         return NULL;
     }
diff --git a/numpy/core/tests/test_ufunc.py b/numpy/core/tests/test_ufunc.py
index ab885bbf0..b3c281e2a 100644
--- a/numpy/core/tests/test_ufunc.py
+++ b/numpy/core/tests/test_ufunc.py
@@ -1095,6 +1095,9 @@ class TestUfunc(TestCase):
         self.assertRaises(TypeError, np.add.at, values, [0, 1], 1)
         assert_array_equal(values, np.array(['a', 1], dtype=np.object))
 
+        # Test multiple output ufuncs raise error, gh-5665
+        assert_raises(ValueError, np.modf.at, np.arange(10), [1])
+
     def test_reduce_arguments(self):
         f = np.add.reduce
         d = np.ones((5,2), dtype=int)