PaperMC/patches/server/0881-Fix-missing-map-initialize-event-call.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Warrior <50800980+Warriorrrr@users.noreply.github.com>
Date: Sun, 24 Sep 2023 18:35:28 +0200
Subject: [PATCH] Fix missing map initialize event call

== AT ==
public net.minecraft.world.level.storage.DimensionDataStorage readSavedData(Ljava/util/function/Function;Lnet/minecraft/util/datafix/DataFixTypes;Ljava/lang/String;)Lnet/minecraft/world/level/saveddata/SavedData;

diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 9270584d74edf5c1af473b1a13f7edca74cc1ec7..1bacbb0d0bd5198d0f946a959b2335d6fba0ca88 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1726,13 +1726,29 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
     @Nullable
     @Override
     public MapItemSavedData getMapData(MapId id) {
-        // CraftBukkit start
-        MapItemSavedData worldmap = (MapItemSavedData) this.getServer().overworld().getDataStorage().get(MapItemSavedData.factory(), id.key());
-        if (worldmap != null) {
-            worldmap.id = id;
+        // Paper start - Call missing map initialize event and set id
+        final DimensionDataStorage storage = this.getServer().overworld().getDataStorage();
+
+        final Optional<net.minecraft.world.level.saveddata.SavedData> cacheEntry = storage.cache.get(id.key());
+        if (cacheEntry == null) { // Cache did not contain, try to load and may init
+            final MapItemSavedData worldmap = storage.get(MapItemSavedData.factory(), id.key()); // get populates the cache
+            if (worldmap != null) { // map was read, init it and return
+                worldmap.id = id;
+                new MapInitializeEvent(worldmap.mapView).callEvent();
+                return worldmap;
+            }
+
+            return null; // Map does not exist, reading failed.
         }
-        return worldmap;
-        // CraftBukkit end
+
+        // Cache entry exists, update it with the id ref and return.
+        if (cacheEntry.orElse(null) instanceof final MapItemSavedData mapItemSavedData) {
+            mapItemSavedData.id = id;
+            return mapItemSavedData;
+        }
+
+        return null;
+        // Paper end - Call missing map initialize event and set id
     }
 
     @Override