From b8102a6767830f02c0c2593725112de51e3330ad Mon Sep 17 00:00:00 2001
From: RogueException <rogueexception@gmail.com>
Date: Thu, 20 Oct 2016 03:53:46 -0300
Subject: [PATCH] Default DependencyMap to an empty map when not supplied

---
 src/Discord.Net.Commands/CommandInfo.cs                | 6 ++++++
 src/Discord.Net.Commands/CommandService.cs             | 2 ++
 src/Discord.Net.Commands/Dependencies/DependencyMap.cs | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/src/Discord.Net.Commands/CommandInfo.cs b/src/Discord.Net.Commands/CommandInfo.cs
index 770dfdb6b..47aae1ae2 100644
--- a/src/Discord.Net.Commands/CommandInfo.cs
+++ b/src/Discord.Net.Commands/CommandInfo.cs
@@ -87,6 +87,9 @@ namespace Discord.Commands
 
         public async Task<PreconditionResult> CheckPreconditions(CommandContext context, IDependencyMap map = null)
         {
+            if (map == null)
+                map = DependencyMap.Empty;
+
             foreach (PreconditionAttribute precondition in Module.Preconditions)
             {
                 var result = await precondition.CheckPermissions(context, this, map).ConfigureAwait(false);
@@ -150,6 +153,9 @@ namespace Discord.Commands
         }
         public async Task<ExecuteResult> Execute(CommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IDependencyMap map)
         {
+            if (map == null)
+                map = DependencyMap.Empty;
+
             try
             {
                 var args = GenerateArgs(argList, paramList);
diff --git a/src/Discord.Net.Commands/CommandService.cs b/src/Discord.Net.Commands/CommandService.cs
index c55f1541d..ef0dba7e7 100644
--- a/src/Discord.Net.Commands/CommandService.cs
+++ b/src/Discord.Net.Commands/CommandService.cs
@@ -195,6 +195,8 @@ namespace Discord.Commands
             => Execute(context, context.Message.Content.Substring(argPos), dependencyMap, multiMatchHandling);
         public async Task<IResult> Execute(CommandContext context, string input, IDependencyMap dependencyMap = null, MultiMatchHandling multiMatchHandling = MultiMatchHandling.Exception)
         {
+            dependencyMap = dependencyMap ?? DependencyMap.Empty;
+
             var searchResult = Search(context, input);
             if (!searchResult.IsSuccess)
                 return searchResult;
diff --git a/src/Discord.Net.Commands/Dependencies/DependencyMap.cs b/src/Discord.Net.Commands/Dependencies/DependencyMap.cs
index d37d69e29..ba5995f26 100644
--- a/src/Discord.Net.Commands/Dependencies/DependencyMap.cs
+++ b/src/Discord.Net.Commands/Dependencies/DependencyMap.cs
@@ -7,6 +7,8 @@ namespace Discord.Commands
     {
         private Dictionary<Type, object> map;
 
+        public static DependencyMap Empty => new DependencyMap();
+
         public DependencyMap()
         {
             map = new Dictionary<Type, object>();