Add a const call mode to Object, Variant and Script.

For this to work safely (user not call queue_free or something in the expression), a const call mode was added to Object and Variant (and optionally Script).

This mode ensures only const functions can be called, making it safe to use from the editor.

Co-Authored-By: reduz <reduzio@gmail.com>

4 files changed, 40 insertions, 0 deletions

diff --git a/core/variant/callable.h b/core/variant/callable.h
index 6a760958d6..bbcf5427ba 100644
--- a/core/variant/callable.h
+++ b/core/variant/callable.h
@@ -61,6 +61,7 @@ public:
 			CALL_ERROR_TOO_MANY_ARGUMENTS, // expected is number of arguments
 			CALL_ERROR_TOO_FEW_ARGUMENTS, // expected is number of arguments
 			CALL_ERROR_INSTANCE_IS_NULL,
+			CALL_ERROR_METHOD_NOT_CONST,
 		};
 		Error error = Error::CALL_OK;
 		int argument = 0;
diff --git a/core/variant/variant.cpp b/core/variant/variant.cpp
index 6007268e21..75aec9a619 100644
--- a/core/variant/variant.cpp
+++ b/core/variant/variant.cpp
@@ -3395,6 +3395,8 @@ String Variant::get_call_error_text(Object *p_base, const StringName &p_method,
 		err_text = "Method not found.";
 	} else if (ce.error == Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL) {
 		err_text = "Instance is null";
+	} else if (ce.error == Callable::CallError::CALL_ERROR_METHOD_NOT_CONST) {
+		err_text = "Method not const in const instance";
 	} else if (ce.error == Callable::CallError::CALL_OK) {
 		return "Call OK";
 	}
diff --git a/core/variant/variant.h b/core/variant/variant.h
index 992d9cad40..83d244145b 100644
--- a/core/variant/variant.h
+++ b/core/variant/variant.h
@@ -555,6 +555,7 @@ public:
 		return ret;
 	}
 
+	void call_const(const StringName &p_method, const Variant **p_args, int p_argcount, Variant &r_ret, Callable::CallError &r_error);
 	static void call_static(Variant::Type p_type, const StringName &p_method, const Variant **p_args, int p_argcount, Variant &r_ret, Callable::CallError &r_error);
 
 	static String get_call_error_text(const StringName &p_method, const Variant **p_argptrs, int p_argcount, const Callable::CallError &ce);
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 8e420ecf04..19c0e35777 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -1031,6 +1031,37 @@ void Variant::callp(const StringName &p_method, const Variant **p_args, int p_ar
 #endif
 		r_ret = _get_obj().obj->callp(p_method, p_args, p_argcount, r_error);
 
+	} else {
+		r_error.error = Callable::CallError::CALL_OK;
+
+		const VariantBuiltInMethodInfo *imf = builtin_method_info[type].lookup_ptr(p_method);
+
+		if (!imf) {
+			r_error.error = Callable::CallError::CALL_ERROR_INVALID_METHOD;
+			return;
+		}
+
+		imf->call(this, p_args, p_argcount, r_ret, imf->default_arguments, r_error);
+	}
+}
+
+void Variant::call_const(const StringName &p_method, const Variant **p_args, int p_argcount, Variant &r_ret, Callable::CallError &r_error) {
+	if (type == Variant::OBJECT) {
+		//call object
+		Object *obj = _get_obj().obj;
+		if (!obj) {
+			r_error.error = Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL;
+			return;
+		}
+#ifdef DEBUG_ENABLED
+		if (EngineDebugger::is_active() && !_get_obj().id.is_ref_counted() && ObjectDB::get_instance(_get_obj().id) == nullptr) {
+			r_error.error = Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL;
+			return;
+		}
+
+#endif
+		r_ret = _get_obj().obj->call_const(p_method, p_args, p_argcount, r_error);
+
 		//else if (type==Variant::METHOD) {
 	} else {
 		r_error.error = Callable::CallError::CALL_OK;
@@ -1042,6 +1073,11 @@ void Variant::callp(const StringName &p_method, const Variant **p_args, int p_ar
 			return;
 		}
 
+		if (!imf->is_const) {
+			r_error.error = Callable::CallError::CALL_ERROR_METHOD_NOT_CONST;
+			return;
+		}
+
 		imf->call(this, p_args, p_argcount, r_ret, imf->default_arguments, r_error);
 	}
 }