From 6adb6b18820cca87a3caac4621177815360cb4e7 Mon Sep 17 00:00:00 2001
From: RogueException <rogueexception@gmail.com>
Date: Sun, 12 Jun 2016 17:08:15 -0300
Subject: [PATCH] Fixed OOB error in MessageCache.Download

---
 src/Discord.Net/{Utilities => Entities/WebSocket}/MessageCache.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
 rename src/Discord.Net/{Utilities => Entities/WebSocket}/MessageCache.cs (92%)

diff --git a/src/Discord.Net/Utilities/MessageCache.cs b/src/Discord.Net/Entities/WebSocket/MessageCache.cs
similarity index 92%
rename from src/Discord.Net/Utilities/MessageCache.cs
rename to src/Discord.Net/Entities/WebSocket/MessageCache.cs
index c0ddf5afd..a0fcbf62c 100644
--- a/src/Discord.Net/Utilities/MessageCache.cs
+++ b/src/Discord.Net/Entities/WebSocket/MessageCache.cs
@@ -104,11 +104,16 @@ namespace Discord
                 return cachedMessages.Skip(cachedMessages.Count - limit).ToImmutableArray();
             else
             {
+                Optional<ulong> relativeId;
+                if (cachedMessages.Count == 0)
+                    relativeId = fromId ?? new Optional<ulong>();
+                else
+                    relativeId = dir == Direction.Before ? cachedMessages[0].Id : cachedMessages[cachedMessages.Count - 1].Id;
                 var args = new GetChannelMessagesParams
                 {
                     Limit = limit - cachedMessages.Count,
                     RelativeDirection = dir,
-                    RelativeMessageId = dir == Direction.Before ? cachedMessages[0].Id : cachedMessages[cachedMessages.Count - 1].Id
+                    RelativeMessageId = relativeId
                 };
                 var downloadedMessages = await _discord.ApiClient.GetChannelMessagesAsync(_channel.Id, args).ConfigureAwait(false);
                 return cachedMessages.Concat(downloadedMessages.Select(x => new CachedMessage(_channel, _channel.GetUser(x.Id), x))).ToImmutableArray();