Break up and make tab spam limits configurable

Due to the changes in 1.13, clients will send a tab completion request
for all bukkit commands in order to factor in the lack of support for
brigadier and provide backwards support in the API.

Craftbukkit, however; has moved the chat spam limiter to also interact
with the tab completion request, which while good for avoiding abuse,
causes 1.13 clients to easilly be kicked from a server in bukkit due
to this. Removing the spam limit could cause issues for servers, however,
there is no way for servers to manipulate this without blindly cancelling
kick events, which only causes additional complications. This also causes
issues in that the tab spam limit and chat share the same field but different
limits, meaning that a player having typed a long command may be kicked from
the server.

Splitting the field up and making it configurable allows for server owners
to take the burden of this into their own hand without having to rely on
plugins doing unsafe things.

This patch has been applied to 1.12.2 in order to allow people using
plugins which allow clients of newer versions to connect, this is
not a common practice, however is being done as a level of nicety
given the current status of 1.13

Spigot-Server-Patches/0096-EntityPathfindEvent.patch

@@ -1,4 +1,4 @@
-From 341c685efb02986f52f829c1a7c56357ce0ad071 Mon Sep 17 00:00:00 2001
+From 51c81d45776fa1901de554be33144437e447d69b Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Mon, 28 Mar 2016 21:22:26 -0400
 Subject: [PATCH] EntityPathfindEvent
@@ -6,7 +6,7 @@ Subject: [PATCH] EntityPathfindEvent
 Fires when an Entity decides to start moving to a location.
 
 diff --git a/src/main/java/net/minecraft/server/NavigationAbstract.java b/src/main/java/net/minecraft/server/NavigationAbstract.java
-index cc44d30b5..3ac6f84d3 100644
+index cc44d30b57..3ac6f84d35 100644
 --- a/src/main/java/net/minecraft/server/NavigationAbstract.java
 +++ b/src/main/java/net/minecraft/server/NavigationAbstract.java
 @@ -4,7 +4,7 @@ import javax.annotation.Nullable;

Spigot-Server-Patches/0129-Don-t-save-empty-scoreboard-teams-to-scoreboard.dat.patch

@@ -1,11 +1,11 @@
-From 046d1dbd3f9ea1948d7d1c66e188f5d1f142b382 Mon Sep 17 00:00:00 2001
+From 6195d48cf4da471efb95da7898c7362fb3806877 Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Sat, 7 May 2016 23:33:08 -0400
 Subject: [PATCH] Don't save empty scoreboard teams to scoreboard.dat
 
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
-index 430b5d0cd..011cbf5e3 100644
+index 430b5d0cdc..011cbf5e31 100644
 --- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
 @@ -225,4 +225,9 @@ public class PaperConfig {
@@ -19,7 +19,7 @@ index 430b5d0cd..011cbf5e3 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/PersistentScoreboard.java b/src/main/java/net/minecraft/server/PersistentScoreboard.java
-index c9c01fad9..89c8d045b 100644
+index c9c01fad91..89c8d045b7 100644
 --- a/src/main/java/net/minecraft/server/PersistentScoreboard.java
 +++ b/src/main/java/net/minecraft/server/PersistentScoreboard.java
 @@ -184,6 +184,7 @@ public class PersistentScoreboard extends PersistentBase {

Spigot-Server-Patches/0346-Break-up-and-make-tab-spam-limits-configurable.patch

@@ -0,0 +1,71 @@
+From 04c3885b1efb9556ac76b285afae2aef2c14f03c Mon Sep 17 00:00:00 2001
+From: Shane Freeder <theboyetronic@gmail.com>
+Date: Sun, 29 Jul 2018 05:02:15 +0100
+Subject: [PATCH] Break up and make tab spam limits configurable
+
+Due to the changes in 1.13, clients will send a tab completion request
+for all bukkit commands in order to factor in the lack of support for
+brigadier and provide backwards support in the API.
+
+Craftbukkit, however; has moved the chat spam limiter to also interact
+with the tab completion request, which while good for avoiding abuse,
+causes 1.13 clients to easilly be kicked from a server in bukkit due
+to this. Removing the spam limit could cause issues for servers, however,
+there is no way for servers to manipulate this without blindly cancelling
+kick events, which only causes additional complications. This also causes
+issues in that the tab spam limit and chat share the same field but different
+limits, meaning that a player having typed a long command may be kicked from
+the server.
+
+Splitting the field up and making it configurable allows for server owners
+to take the burden of this into their own hand without having to rely on
+plugins doing unsafe things.
+
+diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
+index 5a17ce3d22..a5ff014e33 100644
+--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
++++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
+@@ -303,4 +303,11 @@ public class PaperConfig {
+             Bukkit.getLogger().log(Level.INFO, "Using Aikar's Alternative Luck Formula to apply Luck attribute to all loot pool calculations. See https://luckformula.emc.gs");
+         }
+     }
++
++    public static int tabSpamIncrement = 10;
++    public static int tabSpamLimit = 500;
++    private static void tabSpamLimiters() {
++        tabSpamIncrement = getInt("settings.spam-limiter.tab-spam-increment", tabSpamIncrement);
++        tabSpamLimit = getInt("settings.spam-limiter.tab-spam-limit", tabSpamLimit);
++    }
+ }
+diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
+index cc11527390..83d1baf33f 100644
+--- a/src/main/java/net/minecraft/server/PlayerConnection.java
++++ b/src/main/java/net/minecraft/server/PlayerConnection.java
+@@ -74,6 +74,7 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
+     // CraftBukkit start - multithreaded fields
+     private volatile int chatThrottle;
+     private static final AtomicIntegerFieldUpdater chatSpamField = AtomicIntegerFieldUpdater.newUpdater(PlayerConnection.class, "chatThrottle");
++    private final java.util.concurrent.atomic.AtomicInteger tabSpamLimiter = new java.util.concurrent.atomic.AtomicInteger(); // Paper - configurable tab spam limits
+     // CraftBukkit end
+     private int j;
+     private final IntHashMap<Short> k = new IntHashMap();
+@@ -203,6 +204,7 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
+         this.minecraftServer.methodProfiler.b();
+         // CraftBukkit start
+         for (int spam; (spam = this.chatThrottle) > 0 && !chatSpamField.compareAndSet(this, spam, spam - 1); ) ;
++        if (tabSpamLimiter.get() > 0) tabSpamLimiter.getAndDecrement(); // Paper - split to seperate variable
+         /* Use thread-safe field access instead
+         if (this.chatThrottle > 0) {
+             --this.chatThrottle;
+@@ -2281,7 +2283,7 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
+     // Paper start - async tab completion
+     public void a(PacketPlayInTabComplete packet) {
+         // CraftBukkit start
+-        if (chatSpamField.addAndGet(this, 10) > 500 && !this.minecraftServer.getPlayerList().isOp(this.player.getProfile())) {
++        if (tabSpamLimiter.addAndGet(com.destroystokyo.paper.PaperConfig.tabSpamIncrement) > com.destroystokyo.paper.PaperConfig.tabSpamLimit && !this.minecraftServer.getPlayerList().isOp(this.player.getProfile())) { // Paper start - split and make configurable
+             minecraftServer.postToMainThread(() -> this.disconnect(new ChatMessage("disconnect.spam", new Object[0])));
+             return;
+         }
+-- 
+2.18.0
+