From 27288685ffa4480ca603073c657066270afe2d70 Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Sun, 26 Aug 2018 14:39:31 -0400
Subject: [PATCH] Register 1.13+ channels on legacy clients too.

Prior to this commit, Velocity registered 1.13 and "legacy" channels
differently. This commit unifies both for legacy clients to make
compatibility easier. It also fixes a related issue in the new LuckPerms
port to Velocity.
---
 .../proxy/connection/client/ClientPlaySessionHandler.java | 4 ++--
 .../proxy/messages/VelocityChannelRegistrar.java          | 8 +++-----
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java b/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java
index 95dc18b00..9a60be7a4 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java
@@ -45,7 +45,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         if (player.getProtocolVersion() >= ProtocolConstants.MINECRAFT_1_13) {
             message = PluginMessageUtil.constructChannelsPacket("minecraft:register", VelocityServer.getServer().getChannelRegistrar().getModernChannelIds());
         } else {
-            message = PluginMessageUtil.constructChannelsPacket("REGISTER", VelocityServer.getServer().getChannelRegistrar().getLegacyChannelIds());
+            message = PluginMessageUtil.constructChannelsPacket("REGISTER", VelocityServer.getServer().getChannelRegistrar().getIdsForLegacyConnections());
         }
         player.getConnection().write(message);
     }
@@ -188,7 +188,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         if (player.getProtocolVersion() >= ProtocolConstants.MINECRAFT_1_13) {
             toRegister.addAll(VelocityServer.getServer().getChannelRegistrar().getModernChannelIds());
         } else {
-            toRegister.addAll(VelocityServer.getServer().getChannelRegistrar().getLegacyChannelIds());
+            toRegister.addAll(VelocityServer.getServer().getChannelRegistrar().getIdsForLegacyConnections());
         }
         if (!toRegister.isEmpty()) {
             String channel = player.getConnection().getProtocolVersion() >= ProtocolConstants.MINECRAFT_1_13 ?
diff --git a/proxy/src/main/java/com/velocitypowered/proxy/messages/VelocityChannelRegistrar.java b/proxy/src/main/java/com/velocitypowered/proxy/messages/VelocityChannelRegistrar.java
index dff2f5d3e..1fb47cce1 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/messages/VelocityChannelRegistrar.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/messages/VelocityChannelRegistrar.java
@@ -1,6 +1,7 @@
 package com.velocitypowered.proxy.messages;
 
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.proxy.messages.*;
 import com.velocitypowered.proxy.protocol.packet.PluginMessage;
 import org.apache.logging.log4j.LogManager;
@@ -58,11 +59,8 @@ public class VelocityChannelRegistrar implements ChannelRegistrar {
         }
     }
 
-    public Collection<String> getLegacyChannelIds() {
-        return identifierMap.values().stream()
-                .filter(i -> i instanceof LegacyChannelIdentifier)
-                .map(ChannelIdentifier::getId)
-                .collect(Collectors.toList());
+    public Collection<String> getIdsForLegacyConnections() {
+        return ImmutableList.copyOf(identifierMap.keySet());
     }
 
     public Collection<String> getModernChannelIds() {