From 7864570a56f702db9a6f475396660d80202b5b26 Mon Sep 17 00:00:00 2001
From: goat <16760685+goaaats@users.noreply.github.com>
Date: Mon, 14 Feb 2022 04:56:27 +0100
Subject: [PATCH] fix: allow null in CallGateChannel args

---
 .../Ipc/Exceptions/IpcValueNullError.cs       | 21 +++++++++++++++++++
 .../Plugin/Ipc/Internal/CallGateChannel.cs    | 10 ++++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 Dalamud/Plugin/Ipc/Exceptions/IpcValueNullError.cs

diff --git a/Dalamud/Plugin/Ipc/Exceptions/IpcValueNullError.cs b/Dalamud/Plugin/Ipc/Exceptions/IpcValueNullError.cs
new file mode 100644
index 000000000..04d5550a9
--- /dev/null
+++ b/Dalamud/Plugin/Ipc/Exceptions/IpcValueNullError.cs
@@ -0,0 +1,21 @@
+using System;
+
+namespace Dalamud.Plugin.Ipc.Exceptions;
+
+/// <summary>
+/// This exception is thrown when a null value is passed to an IPC requiring a value type.
+/// </summary>
+public class IpcValueNullError : IpcError
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="IpcValueNullError"/> class.
+    /// </summary>
+    /// <param name="name">Name of the IPC.</param>
+    /// <param name="expectedType">The type expected.</param>
+    /// <param name="index">Index of the failing argument.</param>
+    public IpcValueNullError(string name, Type expectedType, int index)
+        : base($"IPC {name} expects a value type({expectedType.FullName}) at index {index}, null given.")
+    {
+        // ignored
+    }
+}
diff --git a/Dalamud/Plugin/Ipc/Internal/CallGateChannel.cs b/Dalamud/Plugin/Ipc/Internal/CallGateChannel.cs
index 7dbda203e..c933b4cd1 100644
--- a/Dalamud/Plugin/Ipc/Internal/CallGateChannel.cs
+++ b/Dalamud/Plugin/Ipc/Internal/CallGateChannel.cs
@@ -105,7 +105,7 @@ namespace Dalamud.Plugin.Ipc.Internal
             var paramTypes = methodInfo.GetParameters()
                 .Select(pi => pi.ParameterType).ToArray();
 
-            if (args.Length != paramTypes.Length)
+            if (args?.Length != paramTypes.Length)
                 throw new IpcLengthMismatchError(this.Name, args.Length, paramTypes.Length);
 
             for (var i = 0; i < args.Length; i++)
@@ -113,6 +113,14 @@ namespace Dalamud.Plugin.Ipc.Internal
                 var arg = args[i];
                 var paramType = paramTypes[i];
 
+                if (arg == null)
+                {
+                    if (paramType.IsValueType)
+                        throw new IpcValueNullError(this.Name, paramType, i);
+
+                    continue;
+                }
+
                 var argType = arg.GetType();
                 if (argType != paramType)
                 {