do not attempt to manually delete derived class instances after TypeManager is terminated and Python is shutting down

pythonnet.sln

@@ -25,6 +25,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Repo", "Repo", "{441A0123-F
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "CI", "CI", "{D301657F-5EAF-4534-B280-B858D651B2E5}"
 	ProjectSection(SolutionItems) = preProject
+		.github\workflows\ARM.yml = .github\workflows\ARM.yml
 		.github\workflows\main.yml = .github\workflows\main.yml
 		.github\workflows\nuget-preview.yml = .github\workflows\nuget-preview.yml
 	EndProjectSection

src/runtime/Runtime.cs

@@ -54,8 +54,9 @@ namespace Python.Runtime
         }
 
         private static bool _isInitialized = false;
-
         internal static bool IsInitialized => _isInitialized;
+        private static bool _typesInitialized = false;
+        internal static bool TypeManagerInitialized => _typesInitialized;
         internal static readonly bool Is32Bit = IntPtr.Size == 4;
 
         // .NET core: System.Runtime.InteropServices.RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
@@ -151,6 +152,7 @@ namespace Python.Runtime
             ClassManager.Reset();
             ClassDerivedObject.Reset();
             TypeManager.Initialize();
+            _typesInitialized = true;
 
             // Initialize modules that depend on the runtime class.
             AssemblyManager.Initialize();
@@ -272,6 +274,7 @@ namespace Python.Runtime
             NullGCHandles(ExtensionType.loadedExtensions);
             ClassManager.RemoveClasses();
             TypeManager.RemoveTypes();
+            _typesInitialized = false;
 
             MetaType.Release();
             PyCLRMetaType.Dispose();
@@ -291,9 +294,10 @@ namespace Python.Runtime
             Finalizer.Shutdown();
             InternString.Shutdown();
 
+            ResetPyMembers();
+
             if (!HostedInPython)
             {
-                ResetPyMembers();
                 GC.Collect();
                 GC.WaitForPendingFinalizers();
                 PyGILState_Release(state);
@@ -310,7 +314,6 @@ namespace Python.Runtime
             }
             else
             {
-                ResetPyMembers();
                 PyGILState_Release(state);
             }
         }

src/runtime/TypeManager.cs

@@ -832,6 +832,7 @@ namespace Python.Runtime
                 var metatype = Runtime.PyObject_TYPE(Type);
                 ManagedType.TryFreeGCHandle(Type, metatype);
             }
+            Runtime.PyType_Modified(Type);
         }
 
         public static IntPtr GetDefaultSlot(int offset)

src/runtime/Types/ClassDerived.cs

@@ -59,10 +59,7 @@ namespace Python.Runtime
             // Decrement the python object's reference count.
             // This doesn't actually destroy the object, it just sets the reference to this object
             // to be a weak reference and it will be destroyed when the C# object is destroyed.
-            if (!self.IsNull())
-            {
-                Runtime.XDecref(self.Steal());
-            }
+            Runtime.XDecref(self.Steal());
 
             return Converter.ToPython(obj, type.Value);
         }
@@ -942,13 +939,16 @@ namespace Python.Runtime
 
             var type = Runtime.PyObject_TYPE(@ref.Borrow());
 
-            // rare case when it's needed
-            // matches correspdonging PyObject_GC_UnTrack
-            // in ClassDerivedObject.tp_dealloc
-            Runtime.PyObject_GC_Del(@ref.Steal());
+            if (!Runtime.HostedInPython || Runtime.TypeManagerInitialized)
+            {
+                // rare case when it's needed
+                // matches correspdonging PyObject_GC_UnTrack
+                // in ClassDerivedObject.tp_dealloc
+                Runtime.PyObject_GC_Del(@ref.Steal());
 
-            // must decref our type
-            Runtime.XDecref(StolenReference.DangerousFromPointer(type.DangerousGetAddress()));
+                // must decref our type
+                Runtime.XDecref(StolenReference.DangerousFromPointer(type.DangerousGetAddress()));
+            }
         }
 
         internal static FieldInfo? GetPyObjField(Type type) => type.GetField(PyObjName, PyObjFlags);