AsyncTabCompleteEvent shouldn't store Immutable Lists

Spigot-API-Patches/0074-AsyncTabCompleteEvent.patch

@@ -1,4 +1,4 @@
-From b1e104401c9584500679340438d6b818f6644c07 Mon Sep 17 00:00:00 2001
+From 661d9fecb9f68354bfd35d767c3256ef1869009c Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Sun, 26 Nov 2017 13:17:09 -0500
 Subject: [PATCH] AsyncTabCompleteEvent
@@ -13,10 +13,10 @@ completion, such as offline players.
 
 diff --git a/src/main/java/com/destroystokyo/paper/event/server/AsyncTabCompleteEvent.java b/src/main/java/com/destroystokyo/paper/event/server/AsyncTabCompleteEvent.java
 new file mode 100644
-index 00000000..1e81fe1c
+index 00000000..2fa4cb1c
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/event/server/AsyncTabCompleteEvent.java
-@@ -0,0 +1,162 @@
+@@ -0,0 +1,167 @@
 +/*
 + * Copyright (c) 2017 Daniel Ennis (Aikar) MIT License
 + *
@@ -42,6 +42,7 @@ index 00000000..1e81fe1c
 +
 +package com.destroystokyo.paper.event.server;
 +
++import com.google.common.collect.ImmutableList;
 +import org.bukkit.Location;
 +import org.bukkit.command.Command;
 +import org.bukkit.command.CommandSender;
@@ -49,6 +50,7 @@ index 00000000..1e81fe1c
 +import org.bukkit.event.Event;
 +import org.bukkit.event.HandlerList;
 +
++import java.util.ArrayList;
 +import java.util.List;
 +
 +/**
@@ -107,6 +109,9 @@ index 00000000..1e81fe1c
 +     * @param completions the new completions
 +     */
 +    public void setCompletions(List<String> completions) {
++        if (completions instanceof ImmutableList) {
++            completions = new ArrayList<>(completions);
++        }
 +        this.completions = completions;
 +    }
 +
@@ -223,5 +228,5 @@ index 6ac437d5..fef57f5f 100644
       * Set the completions offered, overriding any already set.
       *
 -- 
-2.15.0
+2.15.1