init

Author: Lazy-Rabbit-2001

doc/classes/ProjectSettings.xml

@@ -471,6 +471,9 @@
 			Specifies the maximum number of log files allowed (used for rotation). Set to [code]1[/code] to disable log file rotation.
 			If the [code]--log-file <file>[/code] [url=$DOCS_URL/tutorials/editor/command_line_tutorial.html]command line argument[/url] is used, log rotation is always disabled.
 		</member>
+		<member name="debug/gdscript/warnings/access_private_member" 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 class member is accessed from external places, such as accessing a private member from other classes that are not derived from the class where the member is defined.
+		</member>
 		<member name="debug/gdscript/warnings/assert_always_false" type="int" setter="" getter="" default="1">
 			When set to [code]warn[/code] or [code]error[/code], produces a warning or an error respectively when an [code]assert[/code] call always evaluates to [code]false[/code].
 		</member>

modules/gdscript/gdscript_analyzer.cpp

@@ -1946,6 +1946,44 @@ void GDScriptAnalyzer::decide_suite_type(GDScriptParser::Node *p_suite, GDScript
 	}
 }
 
+#ifdef DEBUG_ENABLED
+void GDScriptAnalyzer::check_access_private_member(GDScriptParser::IdentifierNode *p_identifier, const bool p_is_call) {
+	if (p_identifier == nullptr) {
+		return;
+	}
+	if (!String(p_identifier->name).begins_with("_")) {
+		return;
+	}
+	if (parser->current_class->get_datatype().kind != GDScriptParser::DataType::CLASS && parser->current_class->get_datatype().kind != GDScriptParser::DataType::SCRIPT) {
+		return;
+	}
+	if (parser->current_function && parser->current_function->body && parser->current_function->body->has_local(p_identifier->name)) {
+		return;
+	}
+
+	if (parser->current_class->has_member(p_identifier->name)) {
+		if (!p_is_call) {
+			return;
+		}
+		if (ClassDB::has_method(parser->current_class->get_datatype().native_type, p_identifier->name)) {
+			// Ready to implement CALLING_NATIVE_VIRTUAL_METHOD, but here as a comment temporarily
+			//parser->push_warning(p_identifier, GDScriptWarning::CALLING_NATIVE_VIRTUAL_METHOD, p_identifier->name);
+		}
+		return;
+	}
+
+	GDScriptParser::ClassNode *base_class = parser->current_class->base_type.class_type;
+	while (base_class != nullptr) {
+		if (base_class->has_member(p_identifier->name)) {
+			return;
+		}
+		base_class = base_class->base_type.class_type;
+	}
+
+	parser->push_warning(p_identifier, p_is_call ? GDScriptWarning::CALLING_PRIVATE_METHOD : GDScriptWarning::ACCESS_PRIVATE_MEMBER, p_identifier->name);
+}
+#endif // DEBUG_ENABLED
+
 void GDScriptAnalyzer::resolve_suite(GDScriptParser::SuiteNode *p_suite) {
 	for (int i = 0; i < p_suite->statements.size(); i++) {
 		GDScriptParser::Node *stmt = p_suite->statements[i];
@@ -3515,10 +3553,19 @@ void GDScriptAnalyzer::reduce_call(GDScriptParser::CallNode *p_call, bool p_is_a
 		if (p_call->callee == nullptr && current_lambda != nullptr) {
 			push_error("Cannot use `super()` inside a lambda.", p_call);
 		}
+
+#ifdef DEBUG_ENABLED
+		GDScriptParser::IdentifierNode *identifier = static_cast<GDScriptParser::IdentifierNode *>(p_call->callee);
+		check_access_private_member(identifier, true);
+#endif
 	} else if (callee_type == GDScriptParser::Node::IDENTIFIER) {
 		base_type = parser->current_class->get_datatype();
 		base_type.is_meta_type = false;
 		is_self = true;
+#ifdef DEBUG_ENABLED
+		GDScriptParser::IdentifierNode *identifier = static_cast<GDScriptParser::IdentifierNode *>(p_call->callee);
+		check_access_private_member(identifier, true);
+#endif
 	} else if (callee_type == GDScriptParser::Node::SUBSCRIPT) {
 		GDScriptParser::SubscriptNode *subscript = static_cast<GDScriptParser::SubscriptNode *>(p_call->callee);
 		if (subscript->base == nullptr) {
@@ -3552,6 +3599,9 @@ void GDScriptAnalyzer::reduce_call(GDScriptParser::CallNode *p_call, bool p_is_a
 			base_type = subscript->base->get_datatype();
 			is_self = subscript->base->type == GDScriptParser::Node::SELF;
 		}
+#ifdef DEBUG_ENABLED
+		check_access_private_member(subscript->attribute, true);
+#endif
 	} else {
 		// Invalid call. Error already sent in parser.
 		// TODO: Could check if Callable here too.
@@ -4474,6 +4524,10 @@ void GDScriptAnalyzer::reduce_identifier(GDScriptParser::IdentifierNode *p_ident
 			}
 		}
 
+#ifdef DEBUG_ENABLED
+		check_access_private_member(p_identifier);
+#endif
+
 		return;
 	}
 
@@ -4835,6 +4889,10 @@ void GDScriptAnalyzer::reduce_subscript(GDScriptParser::SubscriptNode *p_subscri
 			}
 			result_type.kind = GDScriptParser::DataType::VARIANT;
 		}
+
+#ifdef DEBUG_ENABLED
+		check_access_private_member(p_subscript->attribute);
+#endif
 	} else {
 		if (p_subscript->index == nullptr) {
 			return;

modules/gdscript/gdscript_analyzer.h

@@ -71,6 +71,10 @@ class GDScriptAnalyzer {
 
 	void decide_suite_type(GDScriptParser::Node *p_suite, GDScriptParser::Node *p_statement);
 
+#ifdef DEBUG_ENABLED
+	void check_access_private_member(GDScriptParser::IdentifierNode *p_identifier, const bool p_is_call = false);
+#endif
+
 	void resolve_annotation(GDScriptParser::AnnotationNode *p_annotation);
 	void resolve_class_member(GDScriptParser::ClassNode *p_class, const StringName &p_name, const GDScriptParser::Node *p_source = nullptr);
 	void resolve_class_member(GDScriptParser::ClassNode *p_class, int p_index, const GDScriptParser::Node *p_source = nullptr);

modules/gdscript/gdscript_warning.cpp

@@ -162,6 +162,12 @@ String GDScriptWarning::get_message() const {
 			return vformat(R"*(The default value is using "%s" which won't return nodes in the scene tree before "_ready()" is called. Use the "@onready" annotation to solve this.)*", symbols[0]);
 		case ONREADY_WITH_EXPORT:
 			return R"("@onready" will set the default value after "@export" takes effect and will override it.)";
+		case ACCESS_PRIVATE_MEMBER:
+			CHECK_SYMBOLS(1);
+			return vformat(R"(Trying to access a private member "%s" from an external place, which would cause problems during runtime.)", symbols[0]);
+		case CALLING_PRIVATE_METHOD:
+			CHECK_SYMBOLS(1);
+			return vformat(R"*(Trying to call a private method "%s()" from an external place, which would cause problems during runtime.)*", symbols[0]);
 #ifndef DISABLE_DEPRECATED
 		// Never produced. These warnings migrated from 3.x by mistake.
 		case PROPERTY_USED_AS_FUNCTION: // There is already an error.
@@ -238,6 +244,8 @@ String GDScriptWarning::get_name_from_code(Code p_code) {
 		"NATIVE_METHOD_OVERRIDE",
 		"GET_NODE_DEFAULT_WITHOUT_ONREADY",
 		"ONREADY_WITH_EXPORT",
+		"ACCESS_PRIVATE_MEMBER",
+		"CALLING_PRIVATE_METHOD",
 #ifndef DISABLE_DEPRECATED
 		"PROPERTY_USED_AS_FUNCTION",
 		"CONSTANT_USED_AS_FUNCTION",

modules/gdscript/gdscript_warning.h

@@ -89,6 +89,8 @@ class GDScriptWarning {
 		NATIVE_METHOD_OVERRIDE, // The script method overrides a native one, this may not work as intended.
 		GET_NODE_DEFAULT_WITHOUT_ONREADY, // A class variable uses `get_node()` (or the `$` notation) as its default value, but does not use the @onready annotation.
 		ONREADY_WITH_EXPORT, // The `@onready` annotation will set the value after `@export` which is likely not intended.
+		ACCESS_PRIVATE_MEMBER, // Accessing a private member from external places. E.g. accessing an `_`-prefixed member from other classes that are not derived from the class where the member is defined.
+		CALLING_PRIVATE_METHOD, // Calling a private method from external places. E.g. calling an `_`-prefixed method from other classes that are not derived from the class where the method is defined.
 #ifndef DISABLE_DEPRECATED
 		PROPERTY_USED_AS_FUNCTION, // Function not found, but there's a property with the same name.
 		CONSTANT_USED_AS_FUNCTION, // Function not found, but there's a constant with the same name.
@@ -146,6 +148,8 @@ class GDScriptWarning {
 		ERROR, // NATIVE_METHOD_OVERRIDE // May not work as expected.
 		ERROR, // GET_NODE_DEFAULT_WITHOUT_ONREADY // May not work as expected.
 		ERROR, // ONREADY_WITH_EXPORT // May not work as expected.
+		WARN, // ACCESS_PRIVATE_MEMBER
+		WARN, // CALLING_PRIVATE_METHOD
 #ifndef DISABLE_DEPRECATED
 		WARN, // PROPERTY_USED_AS_FUNCTION
 		WARN, // CONSTANT_USED_AS_FUNCTION