more backporting

src/main/java/org/quiltmc/qsl/frozenblock/core/registry/impl/sync/server/DelayedPacketsHolder.java

@@ -26,5 +26,5 @@
 @ApiStatus.Internal
 public interface DelayedPacketsHolder {
 	void frozenLib$setPacketList(List<ServerboundCustomPayloadPacket> packetList);
-	List<Packet<?>> frozenLib$getPacketList();
+	List<ServerboundCustomPayloadPacket> frozenLib$getPacketList();
 }

src/main/java/org/quiltmc/qsl/frozenblock/core/registry/mixin/PlayerListMixin.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2022 The Quilt Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.quiltmc.qsl.frozenblock.core.registry.mixin;
+
+import net.minecraft.network.Connection;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.server.players.PlayerList;
+import org.quiltmc.qsl.frozenblock.core.registry.impl.sync.server.DelayedPacketsHolder;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(PlayerList.class)
+public class PlayerListMixin {
+
+	@Inject(method = "placeNewPlayer", at = @At("TAIL"))
+	private void sendSync(Connection netManager, ServerPlayer player, CallbackInfo ci) {
+		var delayedList = ((DelayedPacketsHolder) player).frozenLib$getPacketList();
+
+		if (delayedList != null) {
+			for (var packet : delayedList) {
+				packet.handle(player.connection);
+			}
+		}
+
+		((DelayedPacketsHolder) player).frozenLib$setPacketList(null);
+	}
+}

src/main/java/org/quiltmc/qsl/frozenblock/core/registry/mixin/ServerLoginNetworkHandlerMixin.java

@@ -1,19 +1,17 @@
 /*
- * Copyright 2023 FrozenBlock
- * This file is part of FrozenLib.
+ * Copyright 2022 The Quilt Project
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 3 of the License, or (at your option) any later version.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 package org.quiltmc.qsl.frozenblock.core.registry.mixin;
@@ -37,19 +35,19 @@ public abstract class ServerLoginNetworkHandlerMixin {
 
 	@Shadow
 	@Final
-	public Connection connection;
+	Connection connection;
 
 	@Shadow
 	protected abstract void placeNewPlayer(ServerPlayer player);
 
 	@Unique
-	private boolean quilt$continueJoining = false;
+	private boolean frozenLib$continueJoining = false;
 
 	@Inject(method = "placeNewPlayer", at = @At("HEAD"), cancellable = true)
-	private void quilt$applySyncHandler(ServerPlayer player, CallbackInfo ci) {
-		if (!player.server.isSingleplayerOwner(player.getGameProfile()) && !this.quilt$continueJoining && ServerRegistrySync.shouldSync()) {
+	private void applySyncHandler(ServerPlayer player, CallbackInfo ci) {
+		if (!player.server.isSingleplayerOwner(player.getGameProfile()) && !this.frozenLib$continueJoining && ServerRegistrySync.shouldSync()) {
 			this.connection.setListener(new ServerRegistrySyncNetworkHandler(player, this.connection, () -> {
-				this.quilt$continueJoining = true;
+				this.frozenLib$continueJoining = true;
 				this.connection.setListener((PacketListener) this);
 				this.placeNewPlayer(player);
 			}));

src/main/java/org/quiltmc/qsl/frozenblock/core/registry/mixin/ServerPlayerMixin.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2022 The Quilt Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.quiltmc.qsl.frozenblock.core.registry.mixin;
+
+import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.ServerboundCustomPayloadPacket;
+import net.minecraft.server.level.ServerPlayer;
+import org.quiltmc.qsl.frozenblock.core.registry.impl.sync.server.DelayedPacketsHolder;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import java.util.List;
+
+@Mixin(ServerPlayer.class)
+public class ServerPlayerMixin implements DelayedPacketsHolder {
+
+	@Unique
+	private List<ServerboundCustomPayloadPacket> frozenLib$delayedPackets;
+
+	@Override
+	public void frozenLib$setPacketList(List<ServerboundCustomPayloadPacket> packetList) {
+		this.frozenLib$delayedPackets = packetList;
+	}
+
+	@Override
+	public List<ServerboundCustomPayloadPacket> frozenLib$getPacketList() {
+		return this.frozenLib$delayedPackets;
+	}
+}

src/main/resources/mixin/frozenlib_quiltmc_registry.mixins.json

@@ -7,8 +7,10 @@
     "BuiltInRegistriesMixin",
     "ConnectionMixin",
     "MappedRegistryMixin",
+    "PlayerListMixin",
     "RegistryDataLoaderMixin",
     "ServerLoginNetworkHandlerMixin",
+    "ServerPlayerMixin",
     "ServerStatusVersionMixin"
   ],
   "injectors": {