From c891cf32caacb9f449b117fbb984e280d1a60ba5 Mon Sep 17 00:00:00 2001
From: "Andrii Doroshenko (Xrayez)" <xrayez@gmail.com>
Date: Mon, 24 Dec 2018 20:06:35 +0200
Subject: [PATCH] Fix crash when checking empty string for valid hex number

---
 core/ustring.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/core/ustring.cpp b/core/ustring.cpp
index 083a1eaed6..d8b804d484 100644
--- a/core/ustring.cpp
+++ b/core/ustring.cpp
@@ -3578,9 +3578,12 @@ bool String::is_valid_integer() const {
 
 bool String::is_valid_hex_number(bool p_with_prefix) const {
 
-	int from = 0;
 	int len = length();
 
+	if (len == 0)
+		return false;
+
+	int from = 0;
 	if (len != 1 && (operator[](0) == '+' || operator[](0) == '-'))
 		from++;