Lophine/lophine-server/minecraft-patches/features/0059-Leaf-Configurable-vanilla-username-check.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MrHua269 <mrhua269@gmail.com>
Date: Sat, 27 Jun 2026 17:23:22 +0800
Subject: [PATCH] Leaf Configurable vanilla username check

A part of Leaf(https://github.com/Winds-Studio/Leaf/blob/edb0504069139beaa6f39efa4702370c2576b3fc/leaf-server/minecraft-patches/features/0086-Configurable-vanilla-username-check.patch)

License: https://github.com/Winds-Studio/Leaf/blob/edb0504069139beaa6f39efa4702370c2576b3fc/LICENSE.md

diff --git a/net/minecraft/server/MinecraftServer.java b/net/minecraft/server/MinecraftServer.java
index 42ee15c813761702031d5a63f0d080b135be2e0f..1736816e26c255645d62696814cd539ee1ffed8d 100644
--- a/net/minecraft/server/MinecraftServer.java
+++ b/net/minecraft/server/MinecraftServer.java
@@ -217,7 +217,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
     public static final NameAndId ANONYMOUS_PLAYER_PROFILE = new NameAndId(Util.NIL_UUID, "Anonymous Player");
     public static final String SERVER_THREAD_NAME = "Server thread";
     public LevelStorageSource.LevelStorageAccess storageSource;
-    protected final PlayerDataStorage playerDataStorage;
+    public final PlayerDataStorage playerDataStorage;
     private final SavedDataStorage savedDataStorage;
     private final List<Runnable> tickables = Lists.newArrayList();
     // Paper - per-level GameRules
diff --git a/net/minecraft/server/network/ServerLoginPacketListenerImpl.java b/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
index deee051c103f9797f4612e06c12f293ec54724ac..911fb0912c7bc6ab0e29c03a21c6bddb248bbc0a 100644
--- a/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
+++ b/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
@@ -167,11 +167,20 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener,
     public void handleHello(final ServerboundHelloPacket packet) {
         Validate.validState(this.state == ServerLoginPacketListenerImpl.State.HELLO, "Unexpected hello packet");
         // Paper start - Validate usernames
-        if (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.isProxyOnlineMode()
+        // Leaf start - Configurable vanilla username check
+        boolean allPrevChecksPassed;
+        if (me.earthme.luminol.config.modules.misc.UsernameCheckConfig.enabled
+            && io.papermc.paper.configuration.GlobalConfiguration.get().proxies.isProxyOnlineMode()
             && io.papermc.paper.configuration.GlobalConfiguration.get().unsupportedSettings.performUsernameValidation
             && !this.iKnowThisMayNotBeTheBestIdeaButPleaseDisableUsernameValidation) {
-            Validate.validState(StringUtil.isReasonablePlayerName(packet.name()), "Invalid characters in username");
+            allPrevChecksPassed = true;
+            if (!me.earthme.luminol.config.modules.misc.UsernameCheckConfig.allowOldPlayersJoin) {
+                Validate.validState(StringUtil.isReasonablePlayerName(packet.name()), "Invalid characters in username");
+            }
+        } else {
+            allPrevChecksPassed = false;
         }
+        // Leaf end - Configurable vanilla username check
         this.requestedUuid = packet.profileId();
         // Paper end - Validate usernames
         this.requestedUsername = packet.name();
@@ -197,6 +206,15 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener,
                 authenticatorPool.execute(() -> {
                     try {
                         GameProfile gameprofile = ServerLoginPacketListenerImpl.this.createOfflineProfile(ServerLoginPacketListenerImpl.this.requestedUsername); // Spigot
+                        // Leaf start - Configurable vanilla username check
+                        if (me.earthme.luminol.config.modules.misc.UsernameCheckConfig.allowOldPlayersJoin) {
+                            if (server.playerDataStorage.load(new net.minecraft.server.players.NameAndId(gameprofile)).orElse(null) != null) {
+                                server.getPlayerList().playedPlayers.add(packet.name());
+                            } else if (allPrevChecksPassed) {
+                                Validate.validState(StringUtil.isReasonablePlayerName(packet.name()), "Invalid characters in username");
+                            }
+                        }
+                        // Leaf end - Configurable vanilla username check
 
                         gameprofile = ServerLoginPacketListenerImpl.this.callPlayerPreLoginEvents(gameprofile); // Paper - Add more fields to AsyncPlayerPreLoginEvent
                         ServerLoginPacketListenerImpl.LOGGER.info("UUID of player {} is {}", gameprofile.name(), gameprofile.id());
@@ -341,7 +359,7 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener,
         server.getPluginManager().callEvent(asyncEvent);
         profile = asyncEvent.getPlayerProfile();
         profile.complete(true); // Paper - setPlayerProfileAPI
-        gameprofile = com.destroystokyo.paper.profile.CraftPlayerProfile.asAuthlibCopy(profile);
+        gameprofile = com.destroystokyo.paper.profile.CraftPlayerProfile.asAuthlibCopyCustomValidation(profile); // Leaf - Configurable vanilla username check
         playerName = gameprofile.name();
         uniqueId = gameprofile.id();
         // Paper end - Add more fields to AsyncPlayerPreLoginEvent
diff --git a/net/minecraft/server/players/CachedUserNameToIdResolver.java b/net/minecraft/server/players/CachedUserNameToIdResolver.java
index 7443744e3f256983e52a1cefcaf66082e4a46a7b..b7553611723f7120c66e1f3e51d89df28bd2756b 100644
--- a/net/minecraft/server/players/CachedUserNameToIdResolver.java
+++ b/net/minecraft/server/players/CachedUserNameToIdResolver.java
@@ -67,7 +67,7 @@ public class CachedUserNameToIdResolver implements UserNameToIdResolver {
     }
 
     private Optional<NameAndId> lookupGameProfile(final GameProfileRepository profileRepository, final String name) {
-        if (!StringUtil.isValidPlayerName(name)) {
+        if (!StringUtil.isValidPlayerName(name, false)) { // Leaf - Configurable vanilla username check - Directly return, skip unnecessary following logic
             return this.createUnknownProfile(name);
         }
 
diff --git a/net/minecraft/server/players/PlayerList.java b/net/minecraft/server/players/PlayerList.java
index a8f051e6aff31a723a3ba59842fac3a43f4911fe..2939aa1ecd68504424198dd7c90c71c6c1aa4c80 100644
--- a/net/minecraft/server/players/PlayerList.java
+++ b/net/minecraft/server/players/PlayerList.java
@@ -134,6 +134,7 @@ public abstract class PlayerList {
     private org.bukkit.craftbukkit.CraftServer cserver;
     private final Map<String,ServerPlayer> playersByName = new java.util.HashMap<>();
     public @Nullable String collideRuleTeamName; // Paper - Configurable player collision
+    public final List<String> playedPlayers = new java.util.concurrent.CopyOnWriteArrayList<>(); // Leaf - Configurable vanilla username check
 
     // Folia start - region threading
     private final Object connectionsStateLock = new Object();
@@ -581,6 +582,7 @@ public abstract class PlayerList {
         player.getAdvancements().clearTriggers();
         this.players.remove(player);
         this.playersByName.remove(player.getScoreboardName().toLowerCase(java.util.Locale.ROOT)); // Spigot
+        if (me.earthme.luminol.config.modules.misc.UsernameCheckConfig.allowOldPlayersJoin) this.playedPlayers.remove(player.getGameProfile().name()); // Leaf - Configurable vanilla username check
         this.server.getCustomBossEvents().onPlayerDisconnect(player);
         UUID uuid = player.getUUID();
         ServerPlayer serverPlayer = this.playersByUUID.get(uuid);
diff --git a/net/minecraft/util/StringUtil.java b/net/minecraft/util/StringUtil.java
index 7957e0cfc43909c5268698a11c4933d20b4d9155..3de226b84f5c72ae277384b3fda4580a7fa2b43d 100644
--- a/net/minecraft/util/StringUtil.java
+++ b/net/minecraft/util/StringUtil.java
@@ -64,6 +64,15 @@ public class StringUtil {
     }
 
     public static boolean isValidPlayerName(final String name) {
+        // Leaf start - Configurable vanilla username check
+        return isValidPlayerName(name, me.earthme.luminol.config.modules.misc.UsernameCheckConfig.shouldSkipNonPlayerNameCheck());
+    }
+    public static boolean isValidPlayerNameVanilla(final String name) {
+        return name.length() <= 16 && name.chars().filter(i -> i <= 32 || i >= 127).findAny().isEmpty();
+    }
+    public static boolean isValidPlayerName(final String name, final boolean bypassCheck) {
+        if (bypassCheck) return name.length() <= 16;
+        // Leaf end - Configurable vanilla username check
         return name.length() <= 16 && name.chars().filter(c -> c <= 32 || c >= 127).findAny().isEmpty();
     }
 
@@ -87,6 +96,12 @@ public class StringUtil {
 
     // Paper start - Username validation
     public static boolean isReasonablePlayerName(final String name) {
+        // Leaf start - Configurable vanilla username check
+        if (me.earthme.luminol.config.modules.misc.UsernameCheckConfig.allowOldPlayersJoin && net.minecraft.server.MinecraftServer.getServer().getPlayerList().playedPlayers.contains(name)) return true;
+        if (me.earthme.luminol.config.modules.misc.UsernameCheckConfig.useCustomUsernameRegex()) {
+            return me.earthme.luminol.config.modules.misc.UsernameCheckConfig.usernameRegex.matcher(name).matches() && name.length() <= 16; // Leaf - Configurable username check
+        }
+        // Leaf end - Configurable vanilla username check
         if (name.isEmpty() || name.length() > 16) {
             return false;
         }
diff --git a/net/minecraft/world/item/component/ResolvableProfile.java b/net/minecraft/world/item/component/ResolvableProfile.java
index f1b62a6e0d8176d8ba1875e78cc730ee55b1b0c1..3312a751bdd71080bf429990490061bfbf86b758 100644
--- a/net/minecraft/world/item/component/ResolvableProfile.java
+++ b/net/minecraft/world/item/component/ResolvableProfile.java
@@ -68,6 +68,30 @@ public abstract sealed class ResolvableProfile implements TooltipProvider permit
 
     public abstract Either<GameProfile, ResolvableProfile.Partial> unpack();
 
+    // Leaf start - Configurable vanilla username check - Enforce skull validation
+    private static Either<String, UUID> sanitizeDynamicPlayerName(final Either<String, UUID> nameOrId) {
+        if (nameOrId.left().isEmpty()) {
+            return nameOrId;
+        }
+        return me.earthme.luminol.config.modules.misc.UsernameCheckConfig.enforceSkullValidation && !net.minecraft.util.StringUtil.isValidPlayerNameVanilla(nameOrId.left().get()) ? Either.left("INVALID_OWNER") : nameOrId;
+    }
+
+    private static Optional<String> sanitizePartialPlayerName(final Optional<String> name) {
+        if (name.isEmpty()) {
+            return name;
+        }
+        return me.earthme.luminol.config.modules.misc.UsernameCheckConfig.enforceSkullValidation && !net.minecraft.util.StringUtil.isValidPlayerNameVanilla(name.get()) ? Optional.of("INVALID_OWNER") : name;
+    }
+
+    private static Either<GameProfile, ResolvableProfile.Partial> sanitizeStaticPlayerName(final Either<GameProfile, ResolvableProfile.Partial> contents) {
+        if (contents.left().isEmpty()) {
+            return contents;
+        }
+        GameProfile gameProfile = contents.left().get();
+        return me.earthme.luminol.config.modules.misc.UsernameCheckConfig.enforceSkullValidation && !net.minecraft.util.StringUtil.isValidPlayerNameVanilla(gameProfile.name()) ? Either.left(new GameProfile(gameProfile.id(), "INVALID_OWNER", gameProfile.properties())) : contents;
+    }
+    // Leaf end - Configurable vanilla username check - Enforce skull validation
+
     protected ResolvableProfile(final GameProfile partialProfile, final PlayerSkin.Patch skinPatch) {
         this.partialProfile = partialProfile;
         this.skinPatch = skinPatch;
@@ -96,6 +120,7 @@ public abstract sealed class ResolvableProfile implements TooltipProvider permit
         private final Either<String, UUID> nameOrId;
 
         public Dynamic(final Either<String, UUID> nameOrId, final PlayerSkin.Patch skinPatch) {
+            sanitizeDynamicPlayerName(nameOrId); // Leaf - Configurable vanilla username check
             super(ResolvableProfile.createPartialProfile(nameOrId.left(), nameOrId.right(), PropertyMap.EMPTY), skinPatch);
             this.nameOrId = nameOrId;
         }
@@ -135,6 +160,11 @@ public abstract sealed class ResolvableProfile implements TooltipProvider permit
     }
 
     public record Partial(Optional<String> name, Optional<UUID> id, PropertyMap properties) {
+        // Leaf start - Configurable vanilla username check
+        public Partial {
+            name = ResolvableProfile.sanitizePartialPlayerName(name);
+        }
+        // Leaf end - Configurable vanilla username check
         public static final ResolvableProfile.Partial EMPTY = new ResolvableProfile.Partial(Optional.empty(), Optional.empty(), PropertyMap.EMPTY);
         public static final MapCodec<ResolvableProfile.Partial> MAP_CODEC = RecordCodecBuilder.mapCodec(
             i -> i.group(
@@ -165,6 +195,7 @@ public abstract sealed class ResolvableProfile implements TooltipProvider permit
         private final Either<GameProfile, ResolvableProfile.Partial> contents;
 
         public Static(final Either<GameProfile, ResolvableProfile.Partial> contents, final PlayerSkin.Patch skinPatch) {
+            sanitizeStaticPlayerName(contents); // Leaf - Configurable vanilla username check
             super(contents.map(gameProfile -> (GameProfile)gameProfile, ResolvableProfile.Partial::createProfile), skinPatch);
             this.contents = contents;
         }