From 9be8424ef980d7a85e08535de986123033ba55aa Mon Sep 17 00:00:00 2001
From: Rikhardur Bjarni Einarsson <badulf96@gmail.com>
Date: Mon, 29 Apr 2019 23:38:42 +0100
Subject: [PATCH] Added an is_valid function to FuncRef so script can check if
 it is safe to call it.

---
 core/func_ref.cpp | 13 +++++++++++++
 core/func_ref.h   |  1 +
 2 files changed, 14 insertions(+)

diff --git a/core/func_ref.cpp b/core/func_ref.cpp
index 4a965473d95..3d03137d09c 100644
--- a/core/func_ref.cpp
+++ b/core/func_ref.cpp
@@ -51,11 +51,23 @@ void FuncRef::set_instance(Object *p_obj) {
 	ERR_FAIL_NULL(p_obj);
 	id = p_obj->get_instance_id();
 }
+
 void FuncRef::set_function(const StringName &p_func) {
 
 	function = p_func;
 }
 
+bool FuncRef::is_valid() const {
+	if (id == 0)
+		return false;
+
+	Object *obj = ObjectDB::get_instance(id);
+	if (!obj)
+		return false;
+
+	return obj->has_method(function);
+}
+
 void FuncRef::_bind_methods() {
 
 	{
@@ -67,6 +79,7 @@ void FuncRef::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_instance", "instance"), &FuncRef::set_instance);
 	ClassDB::bind_method(D_METHOD("set_function", "name"), &FuncRef::set_function);
+	ClassDB::bind_method(D_METHOD("is_valid"), &FuncRef::is_valid);
 }
 
 FuncRef::FuncRef() :
diff --git a/core/func_ref.h b/core/func_ref.h
index 339279fdbab..a143b58bf0d 100644
--- a/core/func_ref.h
+++ b/core/func_ref.h
@@ -46,6 +46,7 @@ public:
 	Variant call_func(const Variant **p_args, int p_argcount, Variant::CallError &r_error);
 	void set_instance(Object *p_obj);
 	void set_function(const StringName &p_func);
+	bool is_valid() const;
 	FuncRef();
 };