- Ensure python threads are always initialized, even if the main interpreter hasn't initialized them, otherwise attempting to dereference objects in finalizers called by the concurrent GC will fail.

tonyroberts · tonyroberts · commit 95f123ce1d68 · 2014-09-15T13:07:02.000+01:00
- Dispose of PyObject instances after use in CreateSubType rather than wait for the GC
- Don't try and dereference derived class instances after python has shutdown if called from the GC
diff --git a/pythonnet/src/runtime/classderived.cs b/pythonnet/src/runtime/classderived.cs
@@ -519,7 +519,12 @@ public static void Finalize(IPythonDerivedType obj)
 
             // delete the python object in an asnyc task as we may not be able to acquire
             // the GIL immediately and we don't want to block the GC thread.
-            var t = Task.Factory.StartNew(() => {
+            var t = Task.Factory.StartNew(() =>
+            {
+                // If python's been terminated then there's nothing to do
+                if (0 == Runtime.Py_IsInitialized())
+                    return;
+
                 IntPtr gs = Runtime.PyGILState_Ensure();
                 try
                 {
diff --git a/pythonnet/src/runtime/runtime.cs b/pythonnet/src/runtime/runtime.cs
@@ -96,8 +96,12 @@ internal static void Initialize() {
 
         if (0 == Runtime.Py_IsInitialized())
         {
-        Runtime.Py_Initialize();
-        Runtime.PyEval_InitThreads();
+            Runtime.Py_Initialize();
+        }
+
+        if (0 == Runtime.PyEval_ThreadsInitialized())
+        {
+            Runtime.PyEval_InitThreads();
         }
 
 #if (PYTHON32 || PYTHON33 || PYTHON34)
@@ -516,6 +520,11 @@ public unsafe static extern int
     internal unsafe static extern void
     PyEval_InitThreads();
 
+    [DllImport(Runtime.dll, CallingConvention=CallingConvention.Cdecl,
+        ExactSpelling=true, CharSet=CharSet.Ansi)]
+    internal unsafe static extern int
+    PyEval_ThreadsInitialized();
+
     [DllImport(Runtime.dll, CallingConvention=CallingConvention.Cdecl,
         ExactSpelling=true, CharSet=CharSet.Ansi)]
     internal unsafe static extern void
diff --git a/pythonnet/src/runtime/typemanager.cs b/pythonnet/src/runtime/typemanager.cs
@@ -206,20 +206,33 @@ internal static IntPtr CreateSubType(IntPtr py_name, IntPtr py_base_type, IntPtr
             object assembly = null;
             object namespaceStr = null;
 
-            PyObject assemblyKey = new PyObject(Converter.ToPython("__assembly__", typeof(String)));
-            if (0 != Runtime.PyMapping_HasKey(py_dict, assemblyKey.Handle))
+            List<PyObject> disposeList = new List<PyObject>();
+            try
             {
-                PyObject pyAssembly = new PyObject(Runtime.PyDict_GetItem(py_dict, assemblyKey.Handle));
-                if (!Converter.ToManagedValue(pyAssembly.Handle, typeof(String), out assembly, false))
-                    throw new InvalidCastException("Couldn't convert __assembly__ value to string");
-            }
+                PyObject assemblyKey = new PyObject(Converter.ToPython("__assembly__", typeof(String)));
+                disposeList.Add(assemblyKey);
+                if (0 != Runtime.PyMapping_HasKey(py_dict, assemblyKey.Handle))
+                {
+                    PyObject pyAssembly = new PyObject(Runtime.PyDict_GetItem(py_dict, assemblyKey.Handle));
+                    disposeList.Add(pyAssembly);
+                    if (!Converter.ToManagedValue(pyAssembly.Handle, typeof(String), out assembly, false))
+                        throw new InvalidCastException("Couldn't convert __assembly__ value to string");
+                }
 
-            PyObject namespaceKey = new PyObject(Converter.ToPythonImplicit("__namespace__"));
-            if (0 != Runtime.PyMapping_HasKey(py_dict, namespaceKey.Handle))
+                PyObject namespaceKey = new PyObject(Converter.ToPythonImplicit("__namespace__"));
+                disposeList.Add(namespaceKey);
+                if (0 != Runtime.PyMapping_HasKey(py_dict, namespaceKey.Handle))
+                {
+                    PyObject pyNamespace = new PyObject(Runtime.PyDict_GetItem(py_dict, namespaceKey.Handle));
+                    disposeList.Add(pyNamespace);
+                    if (!Converter.ToManagedValue(pyNamespace.Handle, typeof(String), out namespaceStr, false))
+                        throw new InvalidCastException("Couldn't convert __namespace__ value to string");
+                }
+            }
+            finally
             {
-                PyObject pyNamespace = new PyObject(Runtime.PyDict_GetItem(py_dict, namespaceKey.Handle));
-                if (!Converter.ToManagedValue(pyNamespace.Handle, typeof(String), out namespaceStr, false))
-                    throw new InvalidCastException("Couldn't convert __namespace__ value to string");
+                foreach (PyObject o in disposeList)
+                    o.Dispose();
             }
 
             // create the new managed type subclassing the base managed type
