From f8f4cd76cc7e44c8db28544a627be525bc9abe0b Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sat, 25 Aug 2018 21:49:57 +0200
Subject: [PATCH] clear dict when invalidating Py object to fix possible cyclic
 references

---
 src/Base/PyObjectBase.cpp | 7 +++++++
 src/Base/PyObjectBase.h   | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/src/Base/PyObjectBase.cpp b/src/Base/PyObjectBase.cpp
index 25b60eed28..1f3105524d 100644
--- a/src/Base/PyObjectBase.cpp
+++ b/src/Base/PyObjectBase.cpp
@@ -426,3 +426,10 @@ void PyObjectBase::untrackAttribute(const char* attr)
         PyDict_DelItemString(attrDict, attr);
     }
 }
+
+void PyObjectBase::clearAttributes()
+{
+    if (attrDict) {
+        PyDict_Clear(attrDict);
+    }
+}
diff --git a/src/Base/PyObjectBase.h b/src/Base/PyObjectBase.h
index 680623b103..e72ecae03d 100644
--- a/src/Base/PyObjectBase.h
+++ b/src/Base/PyObjectBase.h
@@ -286,6 +286,7 @@ public:
     void setInvalid() { 
         // first bit is not set, i.e. invalid
         StatusBits.reset(Valid);
+        clearAttributes();
         _pcTwinPointer = 0;
     }
 
@@ -320,6 +321,7 @@ private:
     PyObject* getTrackedAttribute(const char* attr);
     void trackAttribute(const char* attr, PyObject* obj);
     void untrackAttribute(const char* attr);
+    void clearAttributes();
 
 protected:
     std::bitset<32> StatusBits;