From 4e54b4ad1c6c5c875845beef1acde2bbd06e0aea Mon Sep 17 00:00:00 2001
From: huangqinjin <huangqinjin@gmail.com>
Date: Mon, 12 Dec 2022 22:52:12 +0800
Subject: [PATCH 1/2] Add builtin converter for None <-> std::nullptr_t

---
 .../python/converter/builtin_converters.hpp   |  4 ++++
 src/converter/builtin_converters.cpp          | 24 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/boost/python/converter/builtin_converters.hpp b/include/boost/python/converter/builtin_converters.hpp
index c2e01c03d3..ff638979d9 100644
--- a/include/boost/python/converter/builtin_converters.hpp
+++ b/include/boost/python/converter/builtin_converters.hpp
@@ -108,6 +108,10 @@ namespace detail
         : ::PyInt_FromLong(x), &PyInt_Type)
 #endif
 
+#ifndef BOOST_NO_CXX11_NULLPTR
+BOOST_PYTHON_TO_PYTHON_BY_VALUE(std::nullptr_t, boost::python::detail::none(), Py_TYPE(Py_None))
+#endif
+
 // Bool is not signed.
 #if PY_VERSION_HEX >= 0x02030000
 BOOST_PYTHON_TO_PYTHON_BY_VALUE(bool, ::PyBool_FromLong(x), &PyBool_Type)
diff --git a/src/converter/builtin_converters.cpp b/src/converter/builtin_converters.cpp
index ee2d5b4794..2286feb496 100644
--- a/src/converter/builtin_converters.cpp
+++ b/src/converter/builtin_converters.cpp
@@ -306,6 +306,26 @@ namespace
   };
 #endif 
 
+#ifndef BOOST_NO_CXX11_NULLPTR
+    struct nullptr_rvalue_from_python
+    {
+        static unaryfunc* get_slot(PyObject* obj)
+        {
+            return obj == Py_None ? &py_object_identity : 0;
+        }
+
+        static std::nullptr_t extract(PyObject*)
+        {
+            return nullptr;
+        }
+
+        static PyTypeObject const* get_pytype()
+        {
+            return Py_TYPE(Py_None);
+        }
+    };
+#endif
+
   // A SlotPolicy for extracting bool from a Python object
   struct bool_rvalue_from_python
   {
@@ -549,6 +569,10 @@ BOOST_PYTHON_DECL PyObject* do_arg_to_python(PyObject* x)
 
 void initialize_builtin_converters()
 {
+#ifndef BOOST_NO_CXX11_NULLPTR
+    slot_rvalue_from_python<std::nullptr_t,nullptr_rvalue_from_python>();
+#endif
+
     // booleans
     slot_rvalue_from_python<bool,bool_rvalue_from_python>();
 

From 1c1db3ad05208fbba8986e6037e84081bbe2864c Mon Sep 17 00:00:00 2001
From: huangqinjin <huangqinjin@gmail.com>
Date: Tue, 13 Dec 2022 20:43:02 +0800
Subject: [PATCH 2/2] Add tests for None <-> nullptr_t conversion

---
 test/builtin_converters.cpp     | 6 ++++++
 test/test_builtin_converters.py | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/test/builtin_converters.cpp b/test/builtin_converters.cpp
index f66e61bd82..2a489f50b9 100644
--- a/test/builtin_converters.cpp
+++ b/test/builtin_converters.cpp
@@ -76,6 +76,9 @@ BOOST_PYTHON_MODULE(builtin_converters_ext)
     def("long_long_size", by_value<BOOST_PYTHON_LONG_LONG>::size);
 #endif
 
+#ifndef BOOST_NO_CXX11_NULLPTR
+    def("rewrap_value_nullptr_t", by_value<std::nullptr_t>::rewrap);
+#endif
     def("rewrap_value_bool", by_value<bool>::rewrap);
     def("rewrap_value_char", by_value<char>::rewrap);
     def("rewrap_value_signed_char", by_value<signed char>::rewrap);
@@ -121,6 +124,9 @@ BOOST_PYTHON_MODULE(builtin_converters_ext)
     def("rewrap_value_mutable_cstring", rewrap_value_mutable_cstring);
 
 
+#ifndef BOOST_NO_CXX11_NULLPTR
+    def("rewrap_const_reference_nullptr_t", by_const_reference<std::nullptr_t>::rewrap);
+#endif
     def("rewrap_const_reference_bool", by_const_reference<bool>::rewrap);
     def("rewrap_const_reference_char", by_const_reference<char>::rewrap);
     def("rewrap_const_reference_signed_char", by_const_reference<signed char>::rewrap);
diff --git a/test/test_builtin_converters.py b/test/test_builtin_converters.py
index 0f1b4ded75..26b3c236cc 100644
--- a/test/test_builtin_converters.py
+++ b/test/test_builtin_converters.py
@@ -32,6 +32,12 @@
 ...     def rewrap_const_reference_unsigned_long_long(x): return long(x)
 >>> if not 'long_long_size' in dir():
 ...     def long_long_size(): return long_size()
+>>> if not 'rewrap_value_nullptr_t' in dir():
+...     def rewrap_value_nullptr_t(x): return x
+...     def rewrap_const_reference_nullptr_t(x): return x
+
+>>> rewrap_value_nullptr_t(None) is None
+True
 
 >>> try: bool_exists = bool
 ... except: pass
@@ -156,6 +162,9 @@
 >>> rewrap_value_mutable_cstring('hello, world')
 'hello, world'
 
+>>> rewrap_const_reference_nullptr_t(None) is None
+True
+
 >>> rewrap_const_reference_bool(None)
 0
 >>> rewrap_const_reference_bool(0)