Fix race condition

prismarine-minecraft-data

@@ -1 +1 @@
-Subproject commit 33abb2dc5dd350f05c8efbeb80835edf01056ff2
+Subproject commit 843fc32877802b9b86ae291a2b2fa3d633c24183

src/main/java/net/minestom/server/network/netty/NettyServer.java

@@ -23,6 +23,8 @@ import net.minestom.server.network.PacketProcessor;
 import net.minestom.server.network.netty.channel.ClientChannel;
 import net.minestom.server.network.netty.codec.*;
 import org.jetbrains.annotations.NotNull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.net.InetSocketAddress;
 import java.util.concurrent.Executors;
@@ -33,6 +35,8 @@ public final class NettyServer {
     private static final long DEFAULT_COMPRESSED_CHANNEL_WRITE_LIMIT = 600_000L;
     private static final long DEFAULT_COMPRESSED_CHANNEL_READ_LIMIT = 100_000L;
 
+    private static final Logger log = LoggerFactory.getLogger(NettyServer.class);
+
     private static final long DEFAULT_UNCOMPRESSED_CHANNEL_WRITE_LIMIT = 15_000_000L;
     private static final long DEFAULT_UNCOMPRESSED_CHANNEL_READ_LIMIT = 1_000_000L;
 
@@ -74,21 +78,29 @@ public final class NettyServer {
             worker = new IOUringEventLoopGroup(); // thread count = core * 2
 
             channel = IOUringServerSocketChannel.class;
+
+            log.info("Using Io_uring");
         } else if (Epoll.isAvailable()) {
             boss = new EpollEventLoopGroup(2);
             worker = new EpollEventLoopGroup(); // thread count = core * 2
 
             channel = EpollServerSocketChannel.class;
+
+            log.info("Using Epoll");
         } else if (KQueue.isAvailable()) {
             boss = new KQueueEventLoopGroup(2);
             worker = new KQueueEventLoopGroup(); // thread count = core * 2
 
             channel = KQueueServerSocketChannel.class;
+
+            log.info("Using KQueue");
         } else {
             boss = new NioEventLoopGroup(2);
             worker = new NioEventLoopGroup(); // thread count = core * 2
 
             channel = NioServerSocketChannel.class;
+
+            log.info("Using Nio");
         }
 
         bootstrap = new ServerBootstrap()

src/main/java/net/minestom/server/utils/cache/TemporaryCache.java

@@ -63,12 +63,13 @@ public class TemporaryCache<T> {
      */
     @Nullable
     public synchronized T retrieve(@NotNull UUID identifier, long lastUpdate) {
-        if (!cacheTime.containsKey(identifier)) {
+        Long tempL = cacheTime.get(identifier);
+        if (tempL == null) {
             return null;
         }
 
-        final long cachedTime = cacheTime.get(identifier);
-        return lastUpdate <= cachedTime ? cache.get(identifier) : null;
+        //cache.get(identifier) will return null if the race condition occurred which is what we want
+        return lastUpdate <= tempL ? cache.get(identifier) : null;
     }
 
     /**

src/test/java/demo/commands/PlayersCommand.java

@@ -19,8 +19,7 @@ public class PlayersCommand extends Command {
     private void usage(CommandSender sender, Arguments arguments) {
         final Collection<Player> players = MinecraftServer.getConnectionManager().getOnlinePlayers();
         final int playerCount = players.size();
-        sender.sendMessage(String.valueOf(playerCount));
-        sender.sendMessage("");
+        sender.sendMessage("Total players: " + playerCount);
         final int limit = 15;
         if (playerCount <= limit) {
             for (final Player player : players) {