session/handler_sub_chunk_request.go: Fixed crash when SubChunkReques…

…t was sent for old dimension.

server/session/handler_sub_chunk_request.go

@@ -2,6 +2,7 @@ package session
 
 import (
 	"github.com/df-mc/dragonfly/server/world"
+	"github.com/sandertv/gophertunnel/minecraft/protocol"
 	"github.com/sandertv/gophertunnel/minecraft/protocol/packet"
 )
 
@@ -12,6 +13,16 @@ type SubChunkRequestHandler struct{}
 // Handle ...
 func (*SubChunkRequestHandler) Handle(p packet.Packet, s *Session, tx *world.Tx, _ Controllable) error {
 	pk := p.(*packet.SubChunkRequest)
+	if dimID, _ := world.DimensionID(tx.World().Dimension()); pk.Dimension != int32(dimID) {
+		// Outdated sub chunk request from a previous dimension.
+		s.writePacket(&packet.SubChunk{
+			Dimension:       pk.Dimension,
+			Position:        pk.Position,
+			CacheEnabled:    s.conn.ClientCacheEnabled(),
+			SubChunkEntries: []protocol.SubChunkEntry{},
+		})
+		return nil
+	}
 	s.ViewSubChunks(world.SubChunkPos(pk.Position), pk.Offsets, tx)
 	return nil
 }