Handle ModConfiguration.Set() for null values (#74)

* Handle ModConfiguration.Set() for null values

Fixes #73

* run `dotnet format`

* Fix the build?

why were we using pull_request_target?

Author: zkxs

.github/workflows/test.yml

@@ -1,4 +1,4 @@
-on: [push, pull_request_target]
+on: [push, pull_request]
 
 env:
   NeosPath: "${{ github.workspace }}/Libs/current/"

NeosModLoader/AssemblyHider.cs

@@ -63,7 +63,7 @@ private static void FindTypePostfix(ref Type? __result)
 					// since this is an edge case users may want to handle in different ways, the HideLateTypes nml config option allows them to choose.
 					bool hideLate = ModLoaderConfiguration.Get().HideLateTypes;
 					Logger.WarnInternal($"The \"{__result}\" type does not appear to part of Neos or a mod. It is unclear whether it should be hidden or not. due to the HideLateTypes config option being {hideLate} it will be {(hideLate ? "Hidden" : "Shown")}");
-					if(hideLate) __result = null;
+					if (hideLate) __result = null;
 				}
 				else
 				{

NeosModLoader/ModConfiguration.cs

@@ -354,19 +354,27 @@ public bool TryGetValue<T>(ModConfigurationKey<T> key, out T? value)
 		/// <param name="key">The key</param>
 		/// <param name="value">The new value</param>
 		/// <param name="eventLabel">A custom label you may assign to this event</param>
-		public void Set(ModConfigurationKey key, object value, string? eventLabel = null)
+		public void Set(ModConfigurationKey key, object? value, string? eventLabel = null)
 		{
 			if (!Definition.TryGetDefiningKey(key, out ModConfigurationKey? definingKey))
 			{
 				throw new KeyNotFoundException($"{key.Name} is not defined in the config definition for {LoadedNeosMod.NeosMod.Name}");
 			}
 
-			if (!definingKey!.ValueType().IsAssignableFrom(value.GetType()))
+			if (value == null)
+			{
+				bool cannotBeNull = definingKey!.ValueType().IsValueType && Nullable.GetUnderlyingType(definingKey!.ValueType()) == null;
+				if (cannotBeNull)
+				{
+					throw new ArgumentException($"null cannot be assigned to {definingKey.ValueType()}");
+				}
+			}
+			else if (!definingKey!.ValueType().IsAssignableFrom(value.GetType()))
 			{
 				throw new ArgumentException($"{value.GetType()} cannot be assigned to {definingKey.ValueType()}");
 			}
 
-			if (!definingKey.Validate(value))
+			if (!definingKey!.Validate(value))
 			{
 				throw new ArgumentException($"\"{value}\" is not a valid value for \"{Owner.Name}{definingKey.Name}\"");
 			}