GDScript: Add validation for `@export_node_path` annotation arguments

Co-authored-by: George Marques <george@gmarqu.es>

3 files changed, 32 insertions, 5 deletions

diff --git a/modules/gdscript/doc_classes/@GDScript.xml b/modules/gdscript/doc_classes/@GDScript.xml
index 0c300eade4..9cc1fc0c31 100644
--- a/modules/gdscript/doc_classes/@GDScript.xml
+++ b/modules/gdscript/doc_classes/@GDScript.xml
@@ -533,6 +533,7 @@
 				[codeblock]
 				@export_node_path("Button", "TouchScreenButton") var some_button
 				[/codeblock]
+				[b]Note:[/b] The type must be a native class or a globally registered script (using the [code]class_name[/code] keyword) that inherits [Node].
 			</description>
 		</annotation>
 		<annotation name="@export_placeholder">
diff --git a/modules/gdscript/gdscript_editor.cpp b/modules/gdscript/gdscript_editor.cpp
index 2a7346940b..2a0a36a062 100644
--- a/modules/gdscript/gdscript_editor.cpp
+++ b/modules/gdscript/gdscript_editor.cpp
@@ -808,9 +808,10 @@ static void _find_annotation_arguments(const GDScriptParser::AnnotationNode *p_a
 		ScriptLanguage::CodeCompletionOption node("Node", ScriptLanguage::CODE_COMPLETION_KIND_CLASS);
 		node.insert_text = node.display.quote(p_quote_style);
 		r_result.insert(node.display, node);
-		List<StringName> node_types;
-		ClassDB::get_inheriters_from_class("Node", &node_types);
-		for (const StringName &E : node_types) {
+
+		List<StringName> native_classes;
+		ClassDB::get_inheriters_from_class("Node", &native_classes);
+		for (const StringName &E : native_classes) {
 			if (!ClassDB::is_class_exposed(E)) {
 				continue;
 			}
@@ -818,6 +819,17 @@ static void _find_annotation_arguments(const GDScriptParser::AnnotationNode *p_a
 			option.insert_text = option.display.quote(p_quote_style);
 			r_result.insert(option.display, option);
 		}
+
+		List<StringName> global_script_classes;
+		ScriptServer::get_global_class_list(&global_script_classes);
+		for (const StringName &E : global_script_classes) {
+			if (!ClassDB::is_parent_class(ScriptServer::get_global_class_native_base(E), "Node")) {
+				continue;
+			}
+			ScriptLanguage::CodeCompletionOption option(E, ScriptLanguage::CODE_COMPLETION_KIND_CLASS);
+			option.insert_text = option.display.quote(p_quote_style);
+			r_result.insert(option.display, option);
+		}
 	} else if (p_annotation->name == SNAME("@warning_ignore")) {
 		for (int warning_code = 0; warning_code < GDScriptWarning::WARNING_MAX; warning_code++) {
 			ScriptLanguage::CodeCompletionOption warning(GDScriptWarning::get_name_from_code((GDScriptWarning::Code)warning_code).to_lower(), ScriptLanguage::CODE_COMPLETION_KIND_PLAIN_TEXT);
diff --git a/modules/gdscript/gdscript_parser.cpp b/modules/gdscript/gdscript_parser.cpp
index 2b91ba8f86..6197cbdcf4 100644
--- a/modules/gdscript/gdscript_parser.cpp
+++ b/modules/gdscript/gdscript_parser.cpp
@@ -3867,6 +3867,7 @@ bool GDScriptParser::export_annotations(const AnnotationNode *p_annotation, Node
 			}
 		}
 
+		// WARNING: Do not merge with the previous `if` because there `!=`, not `==`!
 		if (p_annotation->name == SNAME("@export_flags")) {
 			const int64_t max_flags = 32;
 			Vector<String> t = arg_string.split(":", true, 1);
@@ -3892,6 +3893,18 @@ bool GDScriptParser::export_annotations(const AnnotationNode *p_annotation, Node
 				push_error(vformat(R"(Invalid argument %d of annotation "@export_flags": Starting from argument %d, the flag value must be specified explicitly.)", i + 1, max_flags + 1), p_annotation->arguments[i]);
 				return false;
 			}
+		} else if (p_annotation->name == SNAME("@export_node_path")) {
+			String native_class = arg_string;
+			if (ScriptServer::is_global_class(arg_string)) {
+				native_class = ScriptServer::get_global_class_native_base(arg_string);
+			}
+			if (!ClassDB::class_exists(native_class)) {
+				push_error(vformat(R"(Invalid argument %d of annotation "@export_node_path": The class "%s" was not found in the global scope.)", i + 1, arg_string), p_annotation->arguments[i]);
+				return false;
+			} else if (!ClassDB::is_parent_class(native_class, SNAME("Node"))) {
+				push_error(vformat(R"(Invalid argument %d of annotation "@export_node_path": The class "%s" does not inherit "Node".)", i + 1, arg_string), p_annotation->arguments[i]);
+				return false;
+			}
 		}
 
 		if (i > 0) {
@@ -3909,8 +3922,7 @@ bool GDScriptParser::export_annotations(const AnnotationNode *p_annotation, Node
 		if (export_type.builtin_type == Variant::INT) {
 			variable->export_info.type = Variant::INT;
 		}
-	}
-	if (p_annotation->name == SNAME("@export_multiline")) {
+	} else if (p_annotation->name == SNAME("@export_multiline")) {
 		if (export_type.builtin_type == Variant::ARRAY && export_type.has_container_element_type()) {
 			DataType inner_type = export_type.get_container_element_type();
 			if (inner_type.builtin_type != Variant::STRING) {
@@ -3938,6 +3950,8 @@ bool GDScriptParser::export_annotations(const AnnotationNode *p_annotation, Node
 		}
 	}
 
+	// WARNING: Do not merge with the previous `else if`! Otherwise `else` (default variable type check)
+	// will not work for the above annotations. `@export` and `@export_enum` validate the type separately.
 	if (p_annotation->name == SNAME("@export")) {
 		if (variable->datatype_specifier == nullptr && variable->initializer == nullptr) {
 			push_error(R"(Cannot use simple "@export" annotation with variable without type or initializer, since type can't be inferred.)", p_annotation);