[godot] Port PR #2996 fixes and fix GDExtension shutdown crash

Port from 4.2 branch (PR #2996):
- Fix dangling pointer in SpineSkeletonDataResource destructor by using
  ObjectID validation instead of direct EditorFileSystem access
- Register format loaders/savers at CORE level for GDExtension to fix
  loader/saver registration issues (#2899)

Additional fix for GDExtension:
- Fix crash on editor shutdown by properly removing import/inspector
  plugins in NOTIFICATION_PREDELETE before the extension is unloaded

spine-godot/spine_godot/SpineEditorPlugin.cpp

@@ -197,11 +197,24 @@ Error SpineBinaryResourceImportPlugin::import(const String &source_file, const S
 
 #ifdef SPINE_GODOT_EXTENSION
 SpineEditorPlugin::SpineEditorPlugin() {
-	add_import_plugin(memnew(SpineAtlasResourceImportPlugin));
+	atlas_import_plugin = Ref<EditorImportPlugin>(memnew(SpineAtlasResourceImportPlugin));
-	add_import_plugin(memnew(SpineJsonResourceImportPlugin));
+	json_import_plugin = Ref<EditorImportPlugin>(memnew(SpineJsonResourceImportPlugin));
-	add_import_plugin(memnew(SpineBinaryResourceImportPlugin));
+	binary_import_plugin = Ref<EditorImportPlugin>(memnew(SpineBinaryResourceImportPlugin));
-	add_inspector_plugin(memnew(SpineSkeletonDataResourceInspectorPlugin));
+	skeleton_data_inspector_plugin = Ref<EditorInspectorPlugin>(memnew(SpineSkeletonDataResourceInspectorPlugin));
-	// add_inspector_plugin(memnew(SpineSpriteInspectorPlugin));
+
+	add_import_plugin(atlas_import_plugin);
+	add_import_plugin(json_import_plugin);
+	add_import_plugin(binary_import_plugin);
+	add_inspector_plugin(skeleton_data_inspector_plugin);
+}
+
+void SpineEditorPlugin::_notification(int p_what) {
+	if (p_what == NOTIFICATION_PREDELETE) {
+		remove_import_plugin(atlas_import_plugin);
+		remove_import_plugin(json_import_plugin);
+		remove_import_plugin(binary_import_plugin);
+		remove_inspector_plugin(skeleton_data_inspector_plugin);
+	}
 }
 #else
 SpineEditorPlugin::SpineEditorPlugin(EditorNode *node) {

spine-godot/spine_godot/SpineEditorPlugin.h

@@ -424,6 +424,13 @@ class SpineEditorPlugin : public EditorPlugin {
 	static void _bind_methods() {
 	}
 
+#ifdef SPINE_GODOT_EXTENSION
+	Ref<EditorImportPlugin> atlas_import_plugin;
+	Ref<EditorImportPlugin> json_import_plugin;
+	Ref<EditorImportPlugin> binary_import_plugin;
+	Ref<EditorInspectorPlugin> skeleton_data_inspector_plugin;
+#endif
+
 public:
 #ifdef SPINE_GODOT_EXTENSION
 	explicit SpineEditorPlugin();
@@ -431,6 +438,8 @@ public:
 	String _get_plugin_name() const override {
 		return "SpineEditorPlugin";
 	}
+
+	void _notification(int p_what);
 #else
 	explicit SpineEditorPlugin(EditorNode *node);
 

spine-godot/spine_godot/SpineSkeletonDataResource.cpp

@@ -194,6 +194,8 @@ SpineSkeletonDataResource::SpineSkeletonDataResource() : default_mix(0), skeleto
 	if (Engine::get_singleton()->is_editor_hint()) {
 		EditorFileSystem *efs = get_editor_file_system();
 		if (efs) {
+			// Store the ObjectID for safe validation in destructor
+			editor_file_system_id = efs->get_instance_id();
 			efs->connect("resources_reimported", callable_mp(this, &SpineSkeletonDataResource::_on_resources_reimported));
 		}
 	}
@@ -201,6 +203,8 @@ SpineSkeletonDataResource::SpineSkeletonDataResource() : default_mix(0), skeleto
 	if (Engine::get_singleton()->is_editor_hint()) {
 		EditorFileSystem *efs = EditorFileSystem::get_singleton();
 		if (efs) {
+			// Store the ObjectID for safe validation in destructor
+			editor_file_system_id = efs->get_instance_id();
 			efs->connect("resources_reimported", this, "_on_resources_reimported");
 		}
 	}
@@ -212,14 +216,14 @@ SpineSkeletonDataResource::~SpineSkeletonDataResource() {
 #ifdef TOOLS_ENABLED
 #if VERSION_MAJOR > 3
 	if (Engine::get_singleton()->is_editor_hint()) {
-		EditorFileSystem *efs = get_editor_file_system();
+		EditorFileSystem *efs = Object::cast_to<EditorFileSystem>(ObjectDB::get_instance(editor_file_system_id));
 		if (efs && efs->is_connected("resources_reimported", callable_mp(this, &SpineSkeletonDataResource::_on_resources_reimported))) {
 			efs->disconnect("resources_reimported", callable_mp(this, &SpineSkeletonDataResource::_on_resources_reimported));
 		}
 	}
 #else
 	if (Engine::get_singleton()->is_editor_hint()) {
-		EditorFileSystem *efs = EditorFileSystem::get_singleton();
+		EditorFileSystem *efs = Object::cast_to<EditorFileSystem>(ObjectDB::get_instance(editor_file_system_id));
 		if (efs && efs->is_connected("resources_reimported", this, "_on_resources_reimported")) {
 			efs->disconnect("resources_reimported", this, "_on_resources_reimported");
 		}

spine-godot/spine_godot/SpineSkeletonDataResource.h

@@ -82,6 +82,10 @@ private:
 	spine::SkeletonData *skeleton_data;
 	spine::AnimationStateData *animation_state_data;
 
+#ifdef TOOLS_ENABLED
+	ObjectID editor_file_system_id;
+#endif
+
 	void update_skeleton_data();
 
 #ifdef SPINE_GODOT_EXTENSION

spine-godot/spine_godot/register_types.cpp

@@ -103,6 +103,13 @@ void initialize_spine_godot_module(ModuleInitializationLevel level) {
 #endif
 		return;
 	}
+	if (level == MODULE_INITIALIZATION_LEVEL_CORE) {
+		GDREGISTER_CLASS(SpineAtlasResourceFormatLoader);
+		GDREGISTER_CLASS(SpineAtlasResourceFormatSaver);
+		GDREGISTER_CLASS(SpineSkeletonFileResourceFormatLoader);
+		GDREGISTER_CLASS(SpineSkeletonFileResourceFormatSaver);
+		return;
+	}
 	if (level != MODULE_INITIALIZATION_LEVEL_SCENE) return;
 #else
 #if VERSION_MAJOR > 3
@@ -125,10 +132,12 @@ void register_spine_godot_types() {
 #endif
 	spine::Bone::setYDown(true);
 
+#ifndef SPINE_GODOT_EXTENSION
 	GDREGISTER_CLASS(SpineAtlasResourceFormatLoader);
 	GDREGISTER_CLASS(SpineAtlasResourceFormatSaver);
 	GDREGISTER_CLASS(SpineSkeletonFileResourceFormatLoader);
 	GDREGISTER_CLASS(SpineSkeletonFileResourceFormatSaver);
+#endif
 
 	GDREGISTER_CLASS(SpineObjectWrapper);
 	GDREGISTER_CLASS(SpineAtlasResource);
@@ -221,9 +230,11 @@ void register_spine_godot_types() {
 
 #ifdef SPINE_GODOT_EXTENSION
 void uninitialize_spine_godot_module(ModuleInitializationLevel level) {
-	if (level != MODULE_INITIALIZATION_LEVEL_SCENE) return;
+	if (level == MODULE_INITIALIZATION_LEVEL_SCENE) {
-
 		SpineSprite::clear_statics();
+		return;
+	}
+	if (level != MODULE_INITIALIZATION_LEVEL_CORE) return;
 
 	ResourceLoader::get_singleton()->remove_resource_format_loader(atlas_loader);
 	ResourceSaver::get_singleton()->remove_resource_format_saver(atlas_saver);
@@ -258,7 +269,7 @@ extern "C" GDExtensionBool GDE_EXPORT spine_godot_library_init(GDExtensionInterf
 	GDExtensionBinding::InitObject init_obj(p_get_proc_address, p_library, r_initialization);
 	init_obj.register_initializer(initialize_spine_godot_module);
 	init_obj.register_terminator(uninitialize_spine_godot_module);
-	init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);
+	init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_CORE);
 	return init_obj.init();
 }
 #endif