Trait System

Author: SeremTitus

core/io/resource_loader.cpp

@@ -1525,7 +1525,10 @@ Vector<String> ResourceLoader::list_directory(const String &p_directory) {
 				d = d.substr(0, d.rfind_char('.'));
 			}
 
-			if (d.ends_with(".gdc")) {
+			if (d.ends_with(".t.gdc")) {
+				d = d.substr(0, d.rfind_char('.'));
+				d += ".gdt";
+			} else if (d.ends_with(".gdc")) {
 				d = d.substr(0, d.rfind_char('.'));
 				d += ".gd";
 			}

core/object/object.cpp

@@ -967,6 +967,7 @@ void Object::set_script(const Variant &p_script) {
 	if (!p_script.is_null()) {
 		ERR_FAIL_COND_MSG(s.is_null(), "Cannot set object script. Parameter should be null or a reference to a valid script.");
 		ERR_FAIL_COND_MSG(s->is_abstract(), vformat("Cannot set object script. Script '%s' should not be abstract.", s->get_path()));
+		ERR_FAIL_COND_MSG(!s->is_attachable(), vformat("Cannot set object script. Script '%s' is not attachable.", s->get_path()));
 	}
 
 	script = p_script;

core/object/object.h

@@ -230,6 +230,9 @@ struct MethodInfo {
 	Vector<Variant> default_arguments;
 	int return_val_metadata = 0;
 	Vector<int> arguments_metadata;
+#ifdef TOOLS_ENABLED
+	String overridden_source_path;
+#endif
 
 	int get_argument_meta(int p_arg) const {
 		ERR_FAIL_COND_V(p_arg < -1 || p_arg > arguments.size(), 0);

core/object/script_language.cpp

@@ -171,6 +171,7 @@ void Script::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("is_tool"), &Script::is_tool);
 	ClassDB::bind_method(D_METHOD("is_abstract"), &Script::is_abstract);
+	ClassDB::bind_method(D_METHOD("is_attachable"), &Script::is_attachable);
 
 	ClassDB::bind_method(D_METHOD("get_rpc_config"), &Script::get_rpc_config);
 
@@ -223,7 +224,7 @@ ScriptLanguage *ScriptServer::get_language_for_extension(const String &p_extensi
 	MutexLock lock(languages_mutex);
 
 	for (int i = 0; i < _language_count; i++) {
-		if (_languages[i] && _languages[i]->get_extension() == p_extension) {
+		if (_languages[i] && _languages[i]->get_extensions().has(p_extension)) {
 			return _languages[i];
 		}
 	}
@@ -237,9 +238,25 @@ Error ScriptServer::register_language(ScriptLanguage *p_language) {
 	ERR_FAIL_COND_V_MSG(_language_count >= MAX_LANGUAGES, ERR_UNAVAILABLE, "Script languages limit has been reach, cannot register more.");
 	for (int i = 0; i < _language_count; i++) {
 		const ScriptLanguage *other_language = _languages[i];
-		ERR_FAIL_COND_V_MSG(other_language->get_extension() == p_language->get_extension(), ERR_ALREADY_EXISTS, vformat("A script language with extension '%s' is already registered.", p_language->get_extension()));
+		String shared_extensions;
+		String shared_types;
+		for (String ext : p_language->get_extensions()) {
+			if (other_language->get_extensions().has(ext)) {
+				if (!shared_extensions.is_empty()) {
+					shared_extensions += ", ";
+				}
+				shared_extensions += ext;
+			}
+			if (other_language->get_type_from_extension(ext) == p_language->get_type_from_extension(ext)) {
+				if (!shared_types.is_empty()) {
+					shared_types += ", ";
+				}
+				shared_types += ext;
+			}
+		}
+		ERR_FAIL_COND_V_MSG(!shared_extensions.is_empty(), ERR_ALREADY_EXISTS, vformat("A script language with extension '%s' is already registered.", shared_extensions));
 		ERR_FAIL_COND_V_MSG(other_language->get_name() == p_language->get_name(), ERR_ALREADY_EXISTS, vformat("A script language with name '%s' is already registered.", p_language->get_name()));
-		ERR_FAIL_COND_V_MSG(other_language->get_type() == p_language->get_type(), ERR_ALREADY_EXISTS, vformat("A script language with type '%s' is already registered.", p_language->get_type()));
+		ERR_FAIL_COND_V_MSG(!shared_types.is_empty(), ERR_ALREADY_EXISTS, vformat("A script language with type '%s' is already registered.", shared_types));
 	}
 	_languages[_language_count++] = p_language;
 	return OK;

core/object/script_language.h

@@ -140,6 +140,8 @@ class Script : public Resource {
 	virtual Ref<Script> get_base_script() const = 0; //for script inheritance
 	virtual StringName get_global_name() const = 0;
 	virtual bool inherits_script(const Ref<Script> &p_script) const = 0;
+	virtual bool has_script_subtype(const String &p_type) const { return false; } // For script with possible multiple script types, for instance interfaces or traits(in GDScript).
+	virtual Vector<String> get_script_subtypes() const { return Vector<String>(); }
 
 	virtual StringName get_instance_base_type() const = 0; // this may not work in all scripts, will return empty if so
 	virtual ScriptInstance *instance_create(Object *p_this) = 0;
@@ -169,6 +171,7 @@ class Script : public Resource {
 	virtual bool is_tool() const = 0;
 	virtual bool is_valid() const = 0;
 	virtual bool is_abstract() const = 0;
+	virtual bool is_attachable() const { return true; }
 
 	virtual ScriptLanguage *get_language() const = 0;
 
@@ -219,6 +222,13 @@ class ScriptLanguage : public Object {
 	virtual String get_extension() const = 0;
 	virtual void finish() = 0;
 
+	/* MULTI SCRIPT SUPPORT */
+	// TODO: In the next compat breakage the following methods should be merged by removing there similar method.
+	virtual String get_type_from_extension(const String &p_extension) const { return get_type(); }
+	virtual Vector<String> get_extensions() const { return Vector<String>({ get_extension() }); }
+	virtual Script *create_script_from_extension(const String &p_extension) const { return create_script(); }
+	virtual Ref<Script> make_template_using_extension(const String &p_template, const String &p_class_name, const String &p_base_class_name, const String &p_extension) const { return make_template(p_template, p_class_name, p_base_class_name); }
+
 	/* EDITOR FUNCTIONS */
 	struct Warning {
 		int start_line = -1, end_line = -1;
@@ -272,6 +282,7 @@ class ScriptLanguage : public Object {
 	virtual bool is_using_templates() { return false; }
 	virtual bool validate(const String &p_script, const String &p_path = "", List<String> *r_functions = nullptr, List<ScriptError> *r_errors = nullptr, List<Warning> *r_warnings = nullptr, HashSet<int> *r_safe_lines = nullptr) const = 0;
 	virtual String validate_path(const String &p_path) const { return ""; }
+	virtual bool is_script_attachable(const String &p_extension) const { return true; }
 	virtual Script *create_script() const = 0;
 #ifndef DISABLE_DEPRECATED
 	virtual bool has_named_classes() const = 0;

core/object/script_language_extension.cpp

@@ -38,6 +38,8 @@ void ScriptExtension::_bind_methods() {
 	GDVIRTUAL_BIND(_get_base_script);
 	GDVIRTUAL_BIND(_get_global_name);
 	GDVIRTUAL_BIND(_inherits_script, "script");
+	GDVIRTUAL_BIND(_has_script_subtype, "type");
+	GDVIRTUAL_BIND(_get_script_subtypes);
 
 	GDVIRTUAL_BIND(_get_instance_base_type);
 	GDVIRTUAL_BIND(_instance_create, "for_object");
@@ -65,6 +67,7 @@ void ScriptExtension::_bind_methods() {
 	GDVIRTUAL_BIND(_is_tool);
 	GDVIRTUAL_BIND(_is_valid);
 	GDVIRTUAL_BIND(_is_abstract);
+	GDVIRTUAL_BIND(_is_attachable);
 	GDVIRTUAL_BIND(_get_language);
 
 	GDVIRTUAL_BIND(_has_script_signal, "signal");
@@ -90,7 +93,9 @@ void ScriptLanguageExtension::_bind_methods() {
 	GDVIRTUAL_BIND(_get_name);
 	GDVIRTUAL_BIND(_init);
 	GDVIRTUAL_BIND(_get_type);
+	GDVIRTUAL_BIND(_get_type_from_extension, "extension");
 	GDVIRTUAL_BIND(_get_extension);
+	GDVIRTUAL_BIND(_get_extensions);
 	GDVIRTUAL_BIND(_finish);
 
 	GDVIRTUAL_BIND(_get_reserved_words);
@@ -99,12 +104,15 @@ void ScriptLanguageExtension::_bind_methods() {
 	GDVIRTUAL_BIND(_get_doc_comment_delimiters);
 	GDVIRTUAL_BIND(_get_string_delimiters);
 	GDVIRTUAL_BIND(_make_template, "template", "class_name", "base_class_name");
+	GDVIRTUAL_BIND(_make_template_using_extension, "template", "class_name", "base_class_name", "extension");
 	GDVIRTUAL_BIND(_get_built_in_templates, "object");
 	GDVIRTUAL_BIND(_is_using_templates);
 	GDVIRTUAL_BIND(_validate, "script", "path", "validate_functions", "validate_errors", "validate_warnings", "validate_safe_lines");
 
 	GDVIRTUAL_BIND(_validate_path, "path");
+	GDVIRTUAL_BIND(_is_script_attachable, "extension");
 	GDVIRTUAL_BIND(_create_script);
+	GDVIRTUAL_BIND(_create_script_from_extension, "extension");
 #ifndef DISABLE_DEPRECATED
 	GDVIRTUAL_BIND(_has_named_classes);
 #endif

core/object/script_language_extension.h

@@ -54,6 +54,8 @@ class ScriptExtension : public Script {
 	EXBIND0RC(Ref<Script>, get_base_script)
 	EXBIND0RC(StringName, get_global_name)
 	EXBIND1RC(bool, inherits_script, const Ref<Script> &)
+	EXBIND1RC(bool, has_script_subtype, const String &)
+	EXBIND0RC(Vector<String>, get_script_subtypes)
 	EXBIND0RC(StringName, get_instance_base_type)
 
 	GDVIRTUAL1RC_REQUIRED(GDExtensionPtr<void>, _instance_create, Object *)
@@ -135,7 +137,7 @@ class ScriptExtension : public Script {
 		return GDVIRTUAL_CALL(_is_abstract, abst) && abst;
 	}
 	GDVIRTUAL0RC(bool, _is_abstract)
-
+	EXBIND0RC(bool, is_attachable)
 	EXBIND0RC(ScriptLanguage *, get_language)
 	EXBIND1RC(bool, has_script_signal, const StringName &)
 
@@ -234,7 +236,9 @@ class ScriptLanguageExtension : public ScriptLanguage {
 
 	EXBIND0(init)
 	EXBIND0RC(String, get_type)
+	EXBIND1RC(String, get_type_from_extension, const String &)
 	EXBIND0RC(String, get_extension)
+	EXBIND0RC(Vector<String>, get_extensions)
 	EXBIND0(finish)
 
 	/* EDITOR FUNCTIONS */
@@ -281,6 +285,7 @@ class ScriptLanguageExtension : public ScriptLanguage {
 	}
 
 	EXBIND3RC(Ref<Script>, make_template, const String &, const String &, const String &)
+	EXBIND4RC(Ref<Script>, make_template_using_extension, const String &, const String &, const String &, const String &)
 
 	GDVIRTUAL1RC_REQUIRED(TypedArray<Dictionary>, _get_built_in_templates, StringName)
 
@@ -377,12 +382,15 @@ class ScriptLanguageExtension : public ScriptLanguage {
 	}
 
 	EXBIND1RC(String, validate_path, const String &)
+	EXBIND1RC(bool, is_script_attachable, const String &)
 	GDVIRTUAL0RC_REQUIRED(Object *, _create_script)
 	Script *create_script() const override {
 		Object *ret = nullptr;
 		GDVIRTUAL_CALL(_create_script, ret);
 		return Object::cast_to<Script>(ret);
 	}
+	GDVIRTUAL1RC_REQUIRED(Object *, _create_script_from_extension, const String &)
+	Script *create_script_from_extension(const String &p_extension) const override { return create_script(); }
 #ifndef DISABLE_DEPRECATED
 	EXBIND0RC(bool, has_named_classes)
 #endif

doc/classes/ProjectSettings.xml

@@ -612,6 +612,9 @@
 		<member name="debug/gdscript/warnings/unused_local_constant" type="int" setter="" getter="" default="1">
 			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when a local constant is never used.
 		</member>
+		<member name="debug/gdscript/warnings/unused_onready_overriding_trait" type="int" setter="" getter="" default="1">
+			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when the [annotation @GDScript.@onready] is not used overridden variable from traits and  trait variable uses [annotation @GDScript.@onready].
+		</member>
 		<member name="debug/gdscript/warnings/unused_parameter" type="int" setter="" getter="" default="1">
 			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when a function parameter is never used.
 		</member>
@@ -621,6 +624,9 @@
 		<member name="debug/gdscript/warnings/unused_signal" type="int" setter="" getter="" default="1">
 			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when a signal is declared but never explicitly used in the class.
 		</member>
+		<member name="debug/gdscript/warnings/unused_static_overriding_trait" type="int" setter="" getter="" default="1">
+			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when the [code]static[/code] is not used overridden variable or function from traits and  trait variable or function uses [code]static[/code].
+		</member>
 		<member name="debug/gdscript/warnings/unused_variable" type="int" setter="" getter="" default="1">
 			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when a local variable is unused.
 		</member>

doc/classes/Script.xml

@@ -6,7 +6,7 @@
 	<description>
 		A class stored as a resource. A script extends the functionality of all objects that instantiate it.
 		This is the base class for all scripts and should not be used directly. Trying to create a new script with this class will result in an error.
-		The [code]new[/code] method of a script subclass creates a new instance. [method Object.set_script] extends an existing object, if that object's class matches one of the script's base classes.
+		The [code]new[/code] method of a script subclass creates a new instance. [method Object.set_script] extends an existing object, if that object's class matches one of the script's base classes and if script is attachable check by [method is_attachable].
 	</description>
 	<tutorials>
 		<link title="Scripting documentation index">$DOCS_URL/tutorials/scripting/index.html</link>
@@ -115,6 +115,12 @@
 				Returns [code]true[/code] if the script is an abstract script. An abstract script does not have a constructor and cannot be instantiated.
 			</description>
 		</method>
+		<method name="is_attachable" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if the script is able to be attached to [Object].
+			</description>
+		</method>
 		<method name="is_tool" qualifiers="const">
 			<return type="bool" />
 			<description>

doc/classes/ScriptExtension.xml

@@ -107,6 +107,13 @@
 			<description>
 			</description>
 		</method>
+		<method name="_get_script_subtypes" qualifiers="virtual const">
+			<return type="PackedStringArray" />
+			<description>
+				return other script types.
+				For script with possible multiple script types, for instance interfaces or traits(in GDScript).
+			</description>
+		</method>
 		<method name="_get_source_code" qualifiers="virtual const">
 			<return type="String" />
 			<description>
@@ -130,6 +137,14 @@
 			<description>
 			</description>
 		</method>
+		<method name="_has_script_subtype" qualifiers="virtual const">
+			<return type="bool" />
+			<param index="0" name="type" type="String" />
+			<description>
+				Determines if script is of the given script type.
+				For script with possible multiple script types, for instance interfaces or traits(in GDScript).
+			</description>
+		</method>
 		<method name="_has_source_code" qualifiers="virtual const">
 			<return type="bool" />
 			<description>
@@ -165,6 +180,12 @@
 				Returns [code]true[/code] if the script is an abstract script. An abstract script does not have a constructor and cannot be instantiated.
 			</description>
 		</method>
+		<method name="_is_attachable" qualifiers="virtual const">
+			<return type="bool" />
+			<description>
+				Determines if the script can be attached to [Object]s including [Node]s.
+			</description>
+		</method>
 		<method name="_is_placeholder_fallback_enabled" qualifiers="virtual const">
 			<return type="bool" />
 			<description>

doc/classes/ScriptLanguageExtension.xml

@@ -52,6 +52,14 @@
 			<description>
 			</description>
 		</method>
+		<method name="_create_script_from_extension" qualifiers="virtual const">
+			<return type="Object" />
+			<param index="0" name="extension" type="String" />
+			<description>
+				Creates a new script object based on extension supported by this language.
+				Also look at [method ScriptLanguageExtension._get_extensions].
+			</description>
+		</method>
 		<method name="_debug_get_current_stack_info" qualifiers="virtual">
 			<return type="Dictionary[]" />
 			<description>
@@ -163,6 +171,12 @@
 			<description>
 			</description>
 		</method>
+		<method name="_get_extensions" qualifiers="virtual const">
+			<return type="PackedStringArray" />
+			<description>
+				Returns file extensions of scripts supported by this language.
+			</description>
+		</method>
 		<method name="_get_global_class_name" qualifiers="virtual const">
 			<return type="Dictionary" />
 			<param index="0" name="path" type="String" />
@@ -209,6 +223,14 @@
 			<description>
 			</description>
 		</method>
+		<method name="_get_type_from_extension" qualifiers="virtual const">
+			<return type="String" />
+			<param index="0" name="extension" type="String" />
+			<description>
+				Returns the script type of the given file extension.
+				Also look at [method ScriptLanguageExtension._get_extensions].
+			</description>
+		</method>
 		<method name="_handles_global_class_type" qualifiers="virtual const">
 			<return type="bool" />
 			<param index="0" name="type" type="String" />
@@ -231,6 +253,15 @@
 			<description>
 			</description>
 		</method>
+		<method name="_is_script_attachable" qualifiers="virtual const">
+			<return type="bool" />
+			<param index="0" name="extension" type="String" />
+			<description>
+				Determines if a script can be attached to objects based on the given file extension.
+				Returns true if the script with the specified extension can be attached, false otherwise.
+				Also look at [method ScriptLanguageExtension._get_extensions].
+			</description>
+		</method>
 		<method name="_is_using_templates" qualifiers="virtual">
 			<return type="bool" />
 			<description>
@@ -261,6 +292,15 @@
 			<description>
 			</description>
 		</method>
+		<method name="_make_template_using_extension" qualifiers="virtual const">
+			<return type="Script" />
+			<param index="0" name="template" type="String" />
+			<param index="1" name="class_name" type="String" />
+			<param index="2" name="base_class_name" type="String" />
+			<param index="3" name="extension" type="String" />
+			<description>
+			</description>
+		</method>
 		<method name="_open_in_external_editor" qualifiers="virtual">
 			<return type="int" enum="Error" />
 			<param index="0" name="script" type="Script" />

editor/create_dialog.cpp

@@ -189,12 +189,17 @@ bool CreateDialog::_should_hide_type(const StringName &p_type) const {
 			int i = script_path.find_char('/', 13); // 13 is length of "res://addons/".
 			while (i > -1) {
 				const String plugin_path = script_path.substr(0, i).path_join("plugin.cfg");
-				if (FileAccess::exists(plugin_path)) {
-					return !EditorNode::get_singleton()->is_addon_plugin_enabled(plugin_path);
+				if (FileAccess::exists(plugin_path) && !EditorNode::get_singleton()->is_addon_plugin_enabled(plugin_path)) {
+					return true;
 				}
 				i = script_path.find_char('/', i + 1);
 			}
 		}
+
+		ScriptLanguage *lang = ScriptServer::get_language_for_extension(script_path.get_extension());
+		if (lang && !lang->is_script_attachable(script_path.get_extension())) {
+			return true; // Hide unattachable scripts.
+		}
 	}
 
 	return false;