Update NDArray[object] to be NDArray[numpy.object_] (#5571)

* fix numpy.object_

* style: pre-commit fixes

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

include/pybind11/numpy.h

@@ -1521,7 +1521,7 @@ struct npy_format_descriptor<
     enable_if_t<is_same_ignoring_cvref<T, PyObject *>::value
                 || ((std::is_same<T, handle>::value || std::is_same<T, object>::value)
                     && sizeof(T) == sizeof(PyObject *))>> {
-    static constexpr auto name = const_name("object");
+    static constexpr auto name = const_name("numpy.object_");
 
     static constexpr int value = npy_api::NPY_OBJECT_;
 

tests/test_numpy_array.py

@@ -302,6 +302,13 @@ def test_constructors():
     assert results["array_t<double>"].dtype == np.float64
 
 
+def test_array_object_type(doc):
+    assert (
+        doc(m.pass_array_object_return_as_list)
+        == "pass_array_object_return_as_list(arg0: typing.Annotated[numpy.typing.ArrayLike, numpy.object_]) -> list"
+    )
+
+
 def test_overload_resolution(msg):
     # Exact overload matches:
     assert m.overloaded(np.array([1], dtype="float64")) == "double"