Use strong reference APIs.

For the free-threaded build, it is not safe use borrowed references.
Another thread could deallocate the object and cause the reference to
become invalid.  Replace API calls that borrow references with strong
reference APIs.

Author: nascheme

src/dict.cpp

@@ -68,8 +68,16 @@ object dict_base::get(object_cref k) const
 {
     if (check_exact(this))
     {
+#ifdef Py_GIL_DISABLED
+        PyObject* result;
+        if (PyDict_GetItemRef(this->ptr(),k.ptr(),&result) < 0) {
+            throw_error_already_set();
+        }
+        return object(detail::new_reference(result ? result : Py_None));
+#else
         PyObject* result = PyDict_GetItem(this->ptr(),k.ptr());
         return object(detail::borrowed_reference(result ? result : Py_None));
+#endif
     }
     else
     {

src/object/function_doc_signature.cpp

@@ -135,7 +135,15 @@ namespace boost { namespace python { namespace objects {
             str name(get_qualname(py_type));
             if ( py_type->tp_flags & Py_TPFLAGS_HEAPTYPE ) {
                 // Qualify the type name if it is defined in a different module.
-                PyObject *type_module_name = PyDict_GetItemString(py_type->tp_dict, "__module__");
+                PyObject *type_module_name;
+#if PY_VERSION_HEX >= 0x030D0000
+                if (PyDict_GetItemStringRef(py_type->tp_dict, "__module__", &type_module_name) < 0) {
+                    throw_error_already_set();
+                }
+#else
+                type_module_name = PyDict_GetItemString(py_type->tp_dict, "__module__");
+                Py_XINCREF(type_module_name);
+#endif
                 if (
                     type_module_name
                     && PyObject_RichCompareBool(
@@ -144,8 +152,11 @@ namespace boost { namespace python { namespace objects {
                         Py_NE
                     ) != 0
                 ) {
-                    return str("%s.%s" % make_tuple(handle<>(borrowed(type_module_name)), name));
+                    str result = str("%s.%s" % make_tuple(handle<>(type_module_name), name));
+                    return result;
                 }
+                // Clean up the strong reference if we didn't use it
+                Py_XDECREF(type_module_name);
             }
             return name;
         } else {

src/wrapper.cpp

@@ -21,20 +21,28 @@ namespace detail
                           this->m_self, const_cast<char*>(name))))
           )
           {
-              PyObject* borrowed_f = 0;
-            
+              PyObject* class_f = 0;
+
               if (
                   PyMethod_Check(m.get())
                   && PyMethod_GET_SELF(m.get()) == this->m_self
                   && class_object->tp_dict != 0
               )
               {
-                  borrowed_f = ::PyDict_GetItemString(
+#if PY_VERSION_HEX >= 0x030D0000
+                  if (::PyDict_GetItemStringRef(
+                      class_object->tp_dict, const_cast<char*>(name), &class_f) < 0) {
+                      throw_error_already_set();
+                  }
+#else
+                  class_f = ::PyDict_GetItemString(
                       class_object->tp_dict, const_cast<char*>(name));
-
-
+                  Py_XINCREF(class_f);
+#endif
               }
-              if (borrowed_f != PyMethod_GET_FUNCTION(m.get()))
+              bool is_override = (class_f != PyMethod_GET_FUNCTION(m.get()));
+              Py_XDECREF(class_f);
+              if (is_override)
                   return override(m);
           }
       }