Simplify Player#setInstance

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

@@ -518,27 +518,17 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
     @Override
     public CompletableFuture<Void> setInstance(@NotNull Instance instance, @NotNull Pos spawnPosition) {
         Check.argCondition(this.instance == instance, "Instance should be different than the current one");
-        // true if the chunks need to be sent to the client, can be false if the instances share the same chunks (eg SharedInstance)
+        // true if the chunks need to be sent to the client, can be false if the instances share the same chunks (e.g. SharedInstance)
-        final boolean needWorldRefresh = !InstanceUtils.areLinked(this.instance, instance) ||
+        if (!InstanceUtils.areLinked(this.instance, instance) || !spawnPosition.sameChunk(this.position)) {
-                !spawnPosition.sameChunk(this.position);
-
-        if (needWorldRefresh) {
-            // TODO: Handle player reconnections, must be false in that case too
-            final boolean firstSpawn = this.instance == null;
-
-            // Send the new dimension if player isn't in any instance or if the dimension is different
-            final DimensionType instanceDimensionType = instance.getDimensionType();
-            final boolean dimensionChange = dimensionType != instanceDimensionType;
-            if (dimensionChange) {
-                sendDimension(instanceDimensionType);
-            }
             return instance.loadOptionalChunk(spawnPosition)
-                    .thenRun(() -> spawnPlayer(instance, spawnPosition, firstSpawn, dimensionChange, true));
+                    .thenRun(() -> spawnPlayer(instance, spawnPosition,
+                            this.instance == null,
+                            !Objects.equals(dimensionType, instance.getDimensionType()), true));
         } else {
             // The player already has the good version of all the chunks.
             // We just need to refresh his entity viewing list and add him to the instance
-            spawnPlayer(instance, spawnPosition, false, false, false);
+            return AsyncUtils.VOID_FUTURE
-            return AsyncUtils.NULL_FUTURE;
+                    .thenRun(() -> spawnPlayer(instance, spawnPosition, false, false, false));
         }
     }
 
@@ -586,6 +576,9 @@ public class Player extends LivingEntity implements CommandSender, Localizable,
         }
 
         if (dimensionChange || firstSpawn) {
+            if (dimensionChange) {
+                sendDimension(instance.getDimensionType());
+            }
             synchronizePosition(true); // So the player doesn't get stuck
             this.inventory.update();
         }

src/main/java/net/minestom/server/instance/AnvilLoader.java

@@ -194,7 +194,7 @@ public class AnvilLoader implements IChunkLoader {
                 } catch (AnvilException | IOException e) {
                     LOGGER.error("Failed to save chunk " + chunkX + ", " + chunkZ, e);
                     EXCEPTION_MANAGER.handleException(e);
-                    return AsyncUtils.NULL_FUTURE;
+                    return AsyncUtils.VOID_FUTURE;
                 }
             }
         }
@@ -204,7 +204,7 @@ public class AnvilLoader implements IChunkLoader {
         } catch (AnvilException | IOException e) {
             LOGGER.error("Failed to save chunk " + chunkX + ", " + chunkZ, e);
             EXCEPTION_MANAGER.handleException(e);
-            return AsyncUtils.NULL_FUTURE;
+            return AsyncUtils.VOID_FUTURE;
         }
         save(chunk, column);
         try {
@@ -213,9 +213,9 @@ public class AnvilLoader implements IChunkLoader {
         } catch (IOException e) {
             LOGGER.error("Failed to save chunk " + chunkX + ", " + chunkZ, e);
             EXCEPTION_MANAGER.handleException(e);
-            return AsyncUtils.NULL_FUTURE;
+            return AsyncUtils.VOID_FUTURE;
         }
-        return AsyncUtils.NULL_FUTURE;
+        return AsyncUtils.VOID_FUTURE;
     }
 
     private void save(Chunk chunk, ChunkColumn chunkColumn) {

src/main/java/net/minestom/server/instance/IChunkLoader.java

@@ -56,7 +56,7 @@ public interface IChunkLoader {
             } catch (InterruptedException e) {
                 MinecraftServer.getExceptionManager().handleException(e);
             }
-            return AsyncUtils.NULL_FUTURE;
+            return AsyncUtils.VOID_FUTURE;
         } else {
             CompletableFuture<Void> completableFuture = new CompletableFuture<>();
             AtomicInteger counter = new AtomicInteger();

src/main/java/net/minestom/server/utils/async/AsyncUtils.java

@@ -1,12 +1,14 @@
 package net.minestom.server.utils.async;
 
 import net.minestom.server.MinecraftServer;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.concurrent.CompletableFuture;
 
+@ApiStatus.Internal
 public final class AsyncUtils {
-    public static final CompletableFuture<Void> NULL_FUTURE = CompletableFuture.completedFuture(null);
+    public static final CompletableFuture<Void> VOID_FUTURE = CompletableFuture.completedFuture(null);
 
     public static @NotNull CompletableFuture<Void> runAsync(@NotNull Runnable runnable) {
         return CompletableFuture.runAsync(() -> {