From 0ce18262d0ebcd622444ecc48a36418409b85b93 Mon Sep 17 00:00:00 2001
From: Aeiou <3160746+AeiouEnigma@users.noreply.github.com>
Date: Fri, 24 Dec 2021 19:10:46 -0500
Subject: [PATCH] Add check in LevelLightEngineMixin::construct for whether
 chunkProvider::getLevel returns a Level. Avoids a possible ClassCastException
 in StarLightInterface's constructor if a custom LightChunkGetter which does
 not return a Level from its getLevel is passed as an argument to the
 LevelLightEngine constructor.

---
 .../mixin/common/lightengine/LevelLightEngineMixin.java   | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main/java/ca/spottedleaf/starlight/mixin/common/lightengine/LevelLightEngineMixin.java b/src/main/java/ca/spottedleaf/starlight/mixin/common/lightengine/LevelLightEngineMixin.java
index e66710cd..3ff0d239 100644
--- a/src/main/java/ca/spottedleaf/starlight/mixin/common/lightengine/LevelLightEngineMixin.java
+++ b/src/main/java/ca/spottedleaf/starlight/mixin/common/lightengine/LevelLightEngineMixin.java
@@ -11,6 +11,7 @@
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.SectionPos;
 import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.Level;
 import net.minecraft.world.level.LightLayer;
 import net.minecraft.world.level.chunk.ChunkAccess;
 import net.minecraft.world.level.chunk.DataLayer;
@@ -57,7 +58,12 @@ public final StarLightInterface getLightEngine() {
     )
     public void construct(final LightChunkGetter chunkProvider, final boolean hasBlockLight, final boolean hasSkyLight,
                           final CallbackInfo ci) {
-        this.lightEngine = new StarLightInterface(chunkProvider, hasSkyLight, hasBlockLight, (LevelLightEngine)(Object)this);
+        // avoid ClassCastException in cases where custom LightChunkGetters do not return a Level from getLevel()
+        if (chunkProvider.getLevel() instanceof Level) {
+            this.lightEngine = new StarLightInterface(chunkProvider, hasSkyLight, hasBlockLight, (LevelLightEngine) (Object) this);
+        } else {
+            this.lightEngine = new StarLightInterface(null, hasSkyLight, hasBlockLight, (LevelLightEngine) (Object) this);
+        }
         // intentionally destroy mods hooking into old light engine state
         this.blockEngine = null;
         this.skyEngine = null;