From a2fe33ef1f7a3b405066a14c69cc1a340a763a7f Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sun, 12 Dec 2021 12:15:31 +0100
Subject: [PATCH] World: Section: add support for Int tag section Y values

For some reason, MC1.18 sometimes uses Int instead of Byte tags for
section Y values after "optimize world". Add support for this (but still
only accept values that fit in a int8_t).
---
 src/World/Section.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/World/Section.cpp b/src/World/Section.cpp
index ffa2789..ba7b0c9 100644
--- a/src/World/Section.cpp
+++ b/src/World/Section.cpp
@@ -8,6 +8,7 @@
 #include "Section.hpp"
 #include "../Resource/Biome.hpp"
 #include "../NBT/ByteTag.hpp"
+#include "../NBT/IntTag.hpp"
 #include "../NBT/StringTag.hpp"
 
 #include <cstdio>
@@ -17,7 +18,16 @@ namespace MinedMap {
 namespace World {
 
 Section::Section(const std::shared_ptr<const NBT::CompoundTag> &section) {
-	Y = int8_t(assertValue(section->get<NBT::ByteTag>("Y"))->getValue());
+	const std::shared_ptr<const NBT::ByteTag> YByteTag = section->get<NBT::ByteTag>("Y");
+	if (YByteTag) {
+		Y = int8_t(YByteTag->getValue());
+	} else {
+		const std::shared_ptr<const NBT::IntTag> YIntTag = assertValue(section->get<NBT::IntTag>("Y"));
+		int32_t value = YIntTag->getValue();
+		if (int8_t(value) != value)
+			throw std::invalid_argument("unsupported section Y coordinate");
+		Y = value;
+	}
 	blockLight = section->get<NBT::ByteArrayTag>("BlockLight");
 }