Added nullptr as input for writeonly property

Author: TD22057

docs/classes.rst

@@ -155,6 +155,9 @@ the setter and getter functions:
             .def_property("name", &Pet::getName, &Pet::setName)
             // ... remainder ...
 
+Write only properties can be defined by passing ``nullptr`` as the
+input for the read function.
+
 .. seealso::
 
     Similar functions :func:`class_::def_readwrite_static`,

include/pybind11/pybind11.h

@@ -51,6 +51,7 @@ NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 class cpp_function : public function {
 public:
     cpp_function() { }
+    cpp_function(std::nullptr_t) { }
 
     /// Construct a cpp_function from a vanilla function pointer
     template <typename Return, typename... Args, typename... Extra>

tests/test_methods_and_attributes.cpp

@@ -279,18 +279,18 @@ TEST_SUBMODULE(methods_and_attributes, m) {
         .def(py::init<>())
         .def_readonly("def_readonly", &TestProperties::value)
         .def_readwrite("def_readwrite", &TestProperties::value)
-        .def_property("def_writeonly", py::cpp_function(),
+        .def_property("def_writeonly", nullptr,
                       [](TestProperties& s,int v) { s.value = v; } )
-        .def_property("def_property_writeonly", py::cpp_function(), &TestProperties::set)
+        .def_property("def_property_writeonly", nullptr, &TestProperties::set)
         .def_property_readonly("def_property_readonly", &TestProperties::get)
         .def_property("def_property", &TestProperties::get, &TestProperties::set)
         .def_readonly_static("def_readonly_static", &TestProperties::static_value)
         .def_readwrite_static("def_readwrite_static", &TestProperties::static_value)
-        .def_property_static("def_writeonly_static", py::cpp_function(),
+        .def_property_static("def_writeonly_static", nullptr,
                              [](py::object, int v) { TestProperties::static_value = v; })
         .def_property_readonly_static("def_property_readonly_static",
                                       [](py::object) { return TestProperties::static_get(); })
-        .def_property_static("def_property_writeonly_static", py::cpp_function(),
+        .def_property_static("def_property_writeonly_static", nullptr,
                              [](py::object, int v) { return TestProperties::static_set(v); })
         .def_property_static("def_property_static",
                              [](py::object) { return TestProperties::static_get(); },