An attempt at fixing thread bugs

common/src/main/java/org/valkyrienskies/mod/mixin/world/chunk/MixinLevelChunk.java

@@ -33,6 +33,7 @@
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 import org.valkyrienskies.core.api.ships.Ship;
 import org.valkyrienskies.mod.common.BlockStateInfo;
+import org.valkyrienskies.mod.common.VSGameUtilsKt;
 import org.valkyrienskies.mod.common.util.VSLevelChunk;
 
 @Mixin(LevelChunk.class)
@@ -61,7 +62,10 @@ public MixinLevelChunk(final Ship ship) {
     public void postSetBlockState(final BlockPos pos, final BlockState state, final boolean moved,
         final CallbackInfoReturnable<BlockState> cir) {
         final BlockState prevState = cir.getReturnValue();
-        BlockStateInfo.INSTANCE.onSetBlock(level, pos, prevState, state);
+        // This function is getting invoked by non-game threads for some reason. So use executeOrSchedule() to schedule
+        // onSetBlock() to be run on the next tick when this function is invoked by a non-game thread.
+        // See https://github.com/ValkyrienSkies/Valkyrien-Skies-2/issues/913 for more info.
+        VSGameUtilsKt.executeOrSchedule(level, () -> BlockStateInfo.INSTANCE.onSetBlock(level, pos, prevState, state));
     }
 
     @Shadow

common/src/main/kotlin/org/valkyrienskies/mod/common/VSGameUtils.kt

@@ -10,6 +10,7 @@ import net.minecraft.resources.ResourceLocation
 import net.minecraft.server.MinecraftServer
 import net.minecraft.server.level.ServerChunkCache
 import net.minecraft.server.level.ServerLevel
+import net.minecraft.util.thread.BlockableEventLoop
 import net.minecraft.world.entity.Entity
 import net.minecraft.world.entity.player.Player
 import net.minecraft.world.level.ChunkPos
@@ -408,6 +409,25 @@ fun Level.transformAabbToWorld(aabb: AABBdc, dest: AABBd): AABBd {
     return dest.set(aabb)
 }
 
+/**
+ * Execute [runnable] immediately iff the thread invoking this is the same as the game thread.
+ * Otherwise, schedule [runnable] to run on the next tick.
+ */
+fun Level.executeOrSchedule(runnable: Runnable) {
+    val blockableEventLoop: BlockableEventLoop<Runnable> = if (!this.isClientSide) {
+        this.server!! as BlockableEventLoop<Runnable>
+    } else {
+        Minecraft.getInstance()
+    }
+    if (blockableEventLoop.isSameThread) {
+        // For some reason MinecraftServer wants to schedule even when it's the same thread, so we need to add our own
+        // logic
+        runnable.run()
+    } else {
+        blockableEventLoop.execute(runnable)
+    }
+}
+
 fun getShipMountedToData(passenger: Entity, partialTicks: Float? = null): ShipMountedToData? {
     val vehicle = passenger.vehicle ?: return null
     if (vehicle is ShipMountedToDataProvider) {