From 94886104f3a9fe43bdb28b4b182024bc63a9744a Mon Sep 17 00:00:00 2001
From: AnyOldName3 <krizdjali+github@gmail.com>
Date: Wed, 2 May 2018 00:19:29 +0100
Subject: [PATCH] Prevent the C++ part of PyQt objects being deleted while the
 Python component is still accessible.

---
 src/runner/pythonrunner.cpp | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/runner/pythonrunner.cpp b/src/runner/pythonrunner.cpp
index d987f91..7578949 100644
--- a/src/runner/pythonrunner.cpp
+++ b/src/runner/pythonrunner.cpp
@@ -499,17 +499,33 @@ struct QClass_converters
 {
   struct QClass_to_PyQt
   {
+    template <typename Q>
+    static typename std::enable_if_t<std::is_copy_constructible_v<Q>, T*> getSafeCopy(T *qClass)
+    {
+      return new T(*qClass);
+    }
+
+    template <typename Q>
+    static typename std::enable_if_t<!std::is_copy_constructible_v<Q>, T*> getSafeCopy(T *qClass)
+    {
+      return qClass;
+    }
+
     static PyObject *convert(const T &object) {
       const sipTypeDef *type = sipAPI()->api_find_type(MetaData<T>::className());
       if (type == nullptr) {
         return bpy::incref(Py_None);
       }
 
-      PyObject *sipObj = sipAPI()->api_convert_from_type((void*)(&object), type, 0);
+      PyObject *sipObj = sipAPI()->api_convert_from_type((void*)getSafeCopy<T>((T*)&object), type, 0);
       if (sipObj == nullptr) {
         return bpy::incref(Py_None);
       }
 
+      if (std::is_copy_constructible_v<T>)
+        // Ensure Python deletes the C++ component
+        sipAPI()->api_transfer_back(sipObj);
+
       return bpy::incref(sipObj);
     }
 
@@ -523,11 +539,15 @@ struct QClass_converters
         return bpy::incref(Py_None);
       }
 
-      PyObject *sipObj = sipAPI()->api_convert_from_type(object, type, 0);
+      PyObject *sipObj = sipAPI()->api_convert_from_type(getSafeCopy<T>(object), type, 0);
       if (sipObj == nullptr) {
         return bpy::incref(Py_None);
       }
 
+      if (std::is_copy_constructible_v<T>)
+        // Ensure Python deletes the C++ component
+        sipAPI()->api_transfer_back(sipObj);
+
       return bpy::incref(sipObj);
     }