GDExtension: Prevent issues with the editor trying to reload GDExtensions through its usual mechanism

core/extension/gdextension.cpp

@@ -35,6 +35,7 @@
 #include "core/object/method_bind.h"
 #include "core/os/os.h"
 #include "core/version.h"
+#include "gdextension_manager.h"
 
 extern void gdextension_setup_interface();
 extern GDExtensionInterfaceFunctionPtr gdextension_get_proc_address(const char *p_name);
@@ -949,11 +950,18 @@ Error GDExtensionResourceLoader::load_gdextension_resource(const String &p_path,
 }
 
 Ref<Resource> GDExtensionResourceLoader::load(const String &p_path, const String &p_original_path, Error *r_error, bool p_use_sub_threads, float *r_progress, CacheMode p_cache_mode) {
-	Ref<GDExtension> lib;
-	Error err = load_gdextension_resource(p_path, lib);
-	if (err != OK && r_error) {
-		// Errors already logged in load_gdextension_resource().
-		*r_error = err;
+	// We can't have two GDExtension resource object representing the same library, because
+	// loading (or unloading) a GDExtension affects global data. So, we need reuse the same
+	// object if one has already been loaded (even if caching is disabled at the resource
+	// loader level).
+	GDExtensionManager *manager = GDExtensionManager::get_singleton();
+	Ref<GDExtension> lib = manager->get_extension(p_path);
+	if (lib.is_null()) {
+		Error err = load_gdextension_resource(p_path, lib);
+		if (err != OK && r_error) {
+			// Errors already logged in load_gdextension_resource().
+			*r_error = err;
+		}
 	}
 	return lib;
 }

core/extension/gdextension.h

@@ -112,6 +112,8 @@ protected:
 public:
 	HashMap<String, String> class_icon_paths;
 
+	virtual bool editor_can_reload_from_file() override { return false; } // Reloading is handled in a special way.
+
 	static String get_extension_list_config_file();
 	static String find_extension_library(const String &p_path, Ref<ConfigFile> p_config, std::function<bool(String)> p_has_feature, PackedStringArray *r_tags = nullptr);