From d7b5f51fdc664a4cf6d35f2b7bac375cdfc1aeb6 Mon Sep 17 00:00:00 2001
From: Gary Talent <gtalent2@gmail.com>
Date: Mon, 30 Mar 2020 23:59:01 -0500
Subject: [PATCH] [ox/mc] Prevent reading array length of absent array

---
 deps/ox/src/ox/mc/read.hpp  | 11 +++++++----
 deps/ox/src/ox/mc/write.hpp | 12 ++++++------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/deps/ox/src/ox/mc/read.hpp b/deps/ox/src/ox/mc/read.hpp
index 4f096d67..a9a56492 100644
--- a/deps/ox/src/ox/mc/read.hpp
+++ b/deps/ox/src/ox/mc/read.hpp
@@ -199,10 +199,13 @@ Error MetalClawReader::field(const char*, Handler handler) {
 
 template<typename T>
 Error MetalClawReader::field(const char* name, ox::Vector<T> *val) {
-	const auto [len, err] = arrayLength(false);
-	oxReturnError(err);
-	val->resize(len);
-	return field(name, val->data(), val->size());
+	if (m_fieldPresence.get(m_field)) {
+		const auto [len, err] = arrayLength(false);
+		oxReturnError(err);
+		val->resize(len);
+		return field(name, val->data(), val->size());
+	}
+	return OxError(0);
 }
 
 template<typename T>
diff --git a/deps/ox/src/ox/mc/write.hpp b/deps/ox/src/ox/mc/write.hpp
index f912e16b..3f4382df 100644
--- a/deps/ox/src/ox/mc/write.hpp
+++ b/deps/ox/src/ox/mc/write.hpp
@@ -98,11 +98,6 @@ Error MetalClawWriter::field(const char*, T *val) {
 	return OxError(0);
 }
 
-template<typename T>
-Error MetalClawWriter::field(const char*, ox::Vector<T> *val) {
-	return field(nullptr, val->data(), val->size());
-}
-
 template<typename T>
 Error MetalClawWriter::field(const char*, T *val, std::size_t len) {
 	auto err = OxError(0);
@@ -130,11 +125,16 @@ Error MetalClawWriter::field(const char*, T *val, std::size_t len) {
 		fieldSet = true;
 	}
 
-	err |= m_fieldPresence.set(m_field, fieldSet);
+	oxReturnError(m_fieldPresence.set(m_field, fieldSet));
 	m_field++;
 	return err;
 }
 
+template<typename T>
+Error MetalClawWriter::field(const char*, ox::Vector<T> *val) {
+	return field(nullptr, val->data(), val->size());
+}
+
 template<typename I>
 Error MetalClawWriter::appendInteger(I val) {
 	auto err = OxError(0);