Prevent infinite load screen when not teleporting the player on spawning

src/main/java/net/minestom/server/entity/Player.java

@@ -616,6 +616,16 @@ public class Player extends LivingEntity implements CommandSender {
         return result;
     }
 
+    /**
+     * Changes the player instance and load surrounding chunks if needed.
+     * <p>
+     * Be aware that because chunk operations are expensive,
+     * it is possible for this method to be non-blocking when retrieving chunks is required.
+     * <p>
+     * When this method is called for the first time (during player login), the player will be teleport at {@link #getRespawnPoint()}.
+     *
+     * @param instance the new instance of the player
+     */
     @Override
     public void setInstance(@NotNull Instance instance) {
         Check.notNull(instance, "instance cannot be null!");
@@ -683,6 +693,11 @@ public class Player extends LivingEntity implements CommandSender {
     private void spawnPlayer(Instance instance, boolean firstSpawn) {
         this.viewableEntities.forEach(entity -> entity.removeViewer(this));
         super.setInstance(instance);
+
+        if (firstSpawn) {
+            teleport(getRespawnPoint());
+        }
+
         PlayerSpawnEvent spawnEvent = new PlayerSpawnEvent(this, instance, firstSpawn);
         callEvent(PlayerSpawnEvent.class, spawnEvent);
     }

src/main/java/net/minestom/server/event/player/PlayerLoginEvent.java

@@ -35,7 +35,7 @@ public class PlayerLoginEvent extends Event {
      * <p>
      * WARNING: this must NOT be null, otherwise the player cannot spawn.
      *
-     * @return the spawning instance
+     * @return the spawning instance, null if not already defined
      */
     @Nullable
     public Instance getSpawningInstance() {

src/main/java/net/minestom/server/extras/optifine/OptifineSupport.java

@@ -18,6 +18,8 @@ public final class OptifineSupport {
 
     /**
      * Enables optifine support by registering the required biomes.
+     *
+     * @throws IllegalStateException if optifine support is already enabled
      */
     public static void enable() {
         Check.stateCondition(enabled, "Optifine support is already enabled!");

src/main/java/net/minestom/server/world/biomes/Biome.java

@@ -17,7 +17,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 @EqualsAndHashCode
 public class Biome {
 
-    public static final AtomicInteger idCounter = new AtomicInteger(0);
+    public static final AtomicInteger ID_COUNTER = new AtomicInteger(0);
 
     private static final BiomeEffects DEFAULT_EFFECTS = BiomeEffects.builder()
             .fog_color(0xC0D8FF)
@@ -37,7 +37,7 @@ public class Biome {
             .effects(DEFAULT_EFFECTS)
             .build();
 
-    private final int id = idCounter.getAndIncrement();
+    private final int id = ID_COUNTER.getAndIncrement();
 
     private final NamespaceID name;
     @Builder.Default

src/main/java/net/minestom/server/world/biomes/BiomeManager.java

@@ -15,7 +15,7 @@ import java.util.Collections;
  * <p>
  * Contains {@link Biome#PLAINS} by default but can be removed.
  */
-public class BiomeManager {
+public final class BiomeManager {
 
     private final Int2ObjectMap<Biome> biomes = new Int2ObjectOpenHashMap<>();
 

src/test/java/demo/MainDemo.java

@@ -1,9 +1,7 @@
 package demo;
 
 import net.minestom.server.MinecraftServer;
-import net.minestom.server.entity.GameMode;
 import net.minestom.server.event.player.PlayerLoginEvent;
-import net.minestom.server.event.player.PlayerSpawnEvent;
 import net.minestom.server.instance.*;
 import net.minestom.server.instance.batch.ChunkBatch;
 import net.minestom.server.instance.block.Block;
@@ -34,13 +32,7 @@ public class MainDemo {
             // Set the spawning instance
             player.addEventCallback(PlayerLoginEvent.class, event -> {
                 event.setSpawningInstance(instanceContainer);
-                player.setRespawnPoint(new Position(0,45,0));
-            });
-
-            // Teleport the player at spawn
-            player.addEventCallback(PlayerSpawnEvent.class, event -> {
-                player.teleport(new Position(0, 45, 0));
-                player.setGameMode(GameMode.CREATIVE);
+                player.setRespawnPoint(new Position(0, 45, 0));
             });
         });