Add isInvalidWorld to AsyncPlayerSpawnLocationEvent

paper-api/src/main/java/io/papermc/paper/event/player/AsyncPlayerSpawnLocationEvent.java

@@ -23,14 +23,32 @@ public class AsyncPlayerSpawnLocationEvent extends Event {
 
     private final PlayerConfigurationConnection connection;
     private final boolean newPlayer;
+    private final boolean invalidWorld;
     private Location spawnLocation;
 
     @ApiStatus.Internal
     public AsyncPlayerSpawnLocationEvent(final PlayerConfigurationConnection connection, final Location spawnLocation, final boolean newPlayer) {
+        this(connection, spawnLocation, newPlayer, false);
+    }
+
+    @ApiStatus.Internal
+    public AsyncPlayerSpawnLocationEvent(final PlayerConfigurationConnection connection, final Location spawnLocation, final boolean newPlayer, final boolean invalidWorld) {
         super(true);
         this.connection = connection;
         this.spawnLocation = spawnLocation;
         this.newPlayer = newPlayer;
+        this.invalidWorld = invalidWorld;
+    }
+
+    /**
+     * Returns true if the player's saved data referenced a Bukkit world that is no longer loaded or available.
+     *
+     * <p>When this is true, the server falls back to spawning them in a different world at the same coordinates.</p>
+     *
+     * @return whether the player's saved world was invalid
+     */
+    public boolean isInvalidWorld() {
+        return this.invalidWorld;
     }
 
     /**

paper-server/patches/features/0033-add-isInvalidPlayerWorld-to-Asyncplayerspawnlocationevent.patch

@@ -0,0 +1,57 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Newwind <support@newwindserver.com>
+Date: Sat, 6 Jun 2026 18:00:37 +0200
+Subject: [PATCH] Add isInvalidWorld to AsyncPlayerSpawnLocationEvent
+
+If a world that players are in gets unloaded/reset, they end up spawning in the overworld at the same coordinates they were at, this can cause players die suffocate in walls or fall to their death
+There is no easy way to detect if a player spawn location has had its world changed, this patch fixes that by tracking if the world was determined to be invalid.
+
+diff --git a/net/minecraft/server/network/config/PrepareSpawnTask.java b/net/minecraft/server/network/config/PrepareSpawnTask.java
+index f087b290..ac47509a 100644
+--- a/net/minecraft/server/network/config/PrepareSpawnTask.java
++++ b/net/minecraft/server/network/config/PrepareSpawnTask.java
+@@ -40,6 +40,7 @@ public class PrepareSpawnTask implements ConfigurationTask {
+     private final com.mojang.authlib.GameProfile profile;
+     private final net.minecraft.server.network.ServerConfigurationPacketListenerImpl listener;
+     private boolean newPlayer;
++    private boolean invalidPlayerWorld;
+
+     public PrepareSpawnTask(final MinecraftServer server, final com.mojang.authlib.GameProfile profile, final net.minecraft.server.network.ServerConfigurationPacketListenerImpl listener) {
+         this.profile = profile;
+@@ -59,8 +60,8 @@ public class PrepareSpawnTask implements ConfigurationTask {
+                 .map(tag -> TagValueInput.create(reporter, this.server.registryAccess(), tag));
+             // Paper start - move logic in Entity to here, to use bukkit supplied world UUID & reset to main world spawn if no valid world is found
+             this.newPlayer = loadedData.isEmpty(); // New players don't have saved data!
++            this.invalidPlayerWorld = false;
+             net.minecraft.resources.ResourceKey<net.minecraft.world.level.Level> resourceKey = null; // Paper
+-            boolean[] invalidPlayerWorld = {false};
+             bukkitData: if (loadedData.isPresent()) {
+                 // The main way for bukkit worlds to store the world is the world UUID despite mojang adding custom worlds
+                 final org.bukkit.World bWorld;
+@@ -80,7 +81,7 @@ public class PrepareSpawnTask implements ConfigurationTask {
+                     resourceKey = ((org.bukkit.craftbukkit.CraftWorld) bWorld).getHandle().dimension();
+                 } else {
+                     resourceKey = net.minecraft.world.level.Level.OVERWORLD;
+-                    invalidPlayerWorld[0] = true;
++                    this.invalidPlayerWorld = true;
+                 }
+             }
+             ServerPlayer.SavedPosition loadedPosition = loadedData.<ServerPlayer.SavedPosition>flatMap(tag -> tag.read(ServerPlayer.SavedPosition.MAP_CODEC))
+@@ -102,6 +103,7 @@ public class PrepareSpawnTask implements ConfigurationTask {
+                 if (spawnLevel == null) {
+                     LOGGER.warn("Unknown respawn dimension {}, defaulting to overworld", resourceKey);
+                     spawnLevel = spawnDataLevel;
++                    this.invalidPlayerWorld = true;
+                 }
+             }
+             final ServerLevel finalSpawnLevel = spawnLevel;
+@@ -215,7 +217,8 @@ public class PrepareSpawnTask implements ConfigurationTask {
+                         io.papermc.paper.event.player.AsyncPlayerSpawnLocationEvent ev = new io.papermc.paper.event.player.AsyncPlayerSpawnLocationEvent(
+                             PrepareSpawnTask.this.listener.paperConnection,
+                             org.bukkit.craftbukkit.util.CraftLocation.toBukkit(spawnPositionFinal, this.spawnLevel, this.spawnAngle.x, this.spawnAngle.y),
+-                            PrepareSpawnTask.this.newPlayer
++                            PrepareSpawnTask.this.newPlayer,
++                            PrepareSpawnTask.this.invalidPlayerWorld
+                         );
+                         ev.callEvent();
+                         return ev.getSpawnLocation();