[consider merging] avoid an assertion in the Python exit code for accessing an already destroyed Python object

src/pya/pya/pyaInternal.cc

@@ -859,6 +859,14 @@ PythonClassClientData::PythonClassClientData (const gsi::ClassBase *_cls, PyType
   //  .. nothing yet ..
 }
 
+PythonClassClientData::~PythonClassClientData ()
+{
+  //  This destructor is called from the exit code. Python may have shut down already.
+  //  We must not try to release the objects in that case and simply don't care about them any longer.
+  py_type_object.release ();
+  py_type_object_static.release ();
+}
+
 PyTypeObject *
 PythonClassClientData::py_type (const gsi::ClassBase &cls_decl, bool as_static)
 {

src/pya/pya/pyaInternal.h

@@ -302,6 +302,7 @@ struct PythonClassClientData
   : public gsi::PerClassClientSpecificData
 {
   PythonClassClientData (const gsi::ClassBase *_cls, PyTypeObject *_py_type, PyTypeObject *_py_type_static, PythonModule *module);
+  ~PythonClassClientData ();
 
   PythonPtr py_type_object;
   PythonPtr py_type_object_static;

src/pya/pya/pyaRefs.cc

@@ -151,6 +151,13 @@ PythonPtr::~PythonPtr ()
   Py_XDECREF (mp_obj);
 }
 
+PyObject *PythonPtr::release ()
+{
+  PyObject *obj = mp_obj;
+  mp_obj = NULL;
+  return obj;
+}
+
 PythonPtr::operator bool () const
 {
   return mp_obj != NULL;

src/pya/pya/pyaRefs.h

@@ -211,6 +211,14 @@ public:
     return mp_obj < other.mp_obj;
   }
 
+  /**
+   *  @brief Releases the object
+   *
+   *  This method returns and resets the raw pointer without changing the
+   *  reference count.
+   */
+  PyObject *release ();
+
 private:
   PyObject *mp_obj;
 };