Mono: Script lifetime fixes

- alloc_language_binding: Use strong GC handle as well for references. Fixes #15138
- Set the native instance field of Godot.Object to IntPtr.Zero when it's freed.
- Create weak handles without tracking resurrection (that was causing trouble). This means we have to call notification predelete before queueing a native Object for deletion, and use the MonoObject* passed by the finalizer because the weak GC handle target will return NULL at this point.

1 files changed, 10 insertions, 5 deletions

diff --git a/modules/mono/csharp_script.h b/modules/mono/csharp_script.h
index 255665b495..1a07cf6835 100644
--- a/modules/mono/csharp_script.h
+++ b/modules/mono/csharp_script.h
@@ -167,7 +167,7 @@ class CSharpInstance : public ScriptInstance {
 	bool base_ref;
 	bool ref_dying;
 
-	void _ml_call_reversed(GDMonoClass *klass, const StringName &p_method, const Variant **p_args, int p_argcount);
+	void _ml_call_reversed(MonoObject *p_mono_object, GDMonoClass *klass, const StringName &p_method, const Variant **p_args, int p_argcount);
 
 	void _reference_owner_unsafe();
 	void _unreference_owner_unsafe();
@@ -176,6 +176,8 @@ class CSharpInstance : public ScriptInstance {
 	friend void GDMonoInternals::tie_managed_to_unmanaged(MonoObject *, Object *);
 	static CSharpInstance *create_for_managed_type(Object *p_owner, CSharpScript *p_script, const Ref<MonoGCHandle> &p_gchandle);
 
+	void _call_multilevel(MonoObject *p_mono_object, const StringName &p_method, const Variant **p_args, int p_argcount);
+
 public:
 	MonoObject *get_mono_object() const;
 
@@ -192,13 +194,14 @@ public:
 
 	void mono_object_disposed();
 
-	void refcount_incremented();
-	bool refcount_decremented();
+	virtual void refcount_incremented();
+	virtual bool refcount_decremented();
 
-	RPCMode get_rpc_mode(const StringName &p_method) const;
-	RPCMode get_rset_mode(const StringName &p_variable) const;
+	virtual RPCMode get_rpc_mode(const StringName &p_method) const;
+	virtual RPCMode get_rset_mode(const StringName &p_variable) const;
 
 	virtual void notification(int p_notification);
+	void call_notification_no_check(MonoObject *p_mono_object, int p_notification);
 
 	virtual Ref<Script> get_script() const;
 
@@ -215,6 +218,8 @@ class CSharpLanguage : public ScriptLanguage {
 
 	static CSharpLanguage *singleton;
 
+	bool finalizing;
+
 	GDMono *gdmono;
 	SelfList<CSharpScript>::List script_list;