enable nullable annotations in SMAPI where no logic changes are needed (#837)

7 files changed, 50 insertions, 48 deletions

diff --git a/src/SMAPI/Framework/ModHelpers/ContentHelper.cs b/src/SMAPI/Framework/ModHelpers/ContentHelper.cs
index 12ef0439..b610b395 100644
--- a/src/SMAPI/Framework/ModHelpers/ContentHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/ContentHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
@@ -114,6 +112,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         public T Load<T>(string key, ContentSource source = ContentSource.ModFolder)
+            where T : notnull
         {
             IAssetName assetName = this.ContentCore.ParseAssetName(key, allowLocales: source == ContentSource.GameContent);
 
@@ -140,7 +139,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         [Pure]
-        public string NormalizeAssetName(string assetName)
+        public string NormalizeAssetName(string? assetName)
         {
             return this.ModContentManager.AssertAndNormalizeAssetName(assetName);
         }
@@ -171,6 +170,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         public bool InvalidateCache<T>()
+            where T : notnull
         {
             this.Monitor.Log($"Requested cache invalidation for all assets of type {typeof(T)}. This is an expensive operation and should be avoided if possible.");
             return this.ContentCore.InvalidateCache((_, _, type) => typeof(T).IsAssignableFrom(type)).Any();
@@ -184,7 +184,8 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public IAssetData GetPatchHelper<T>(T data, string assetName = null)
+        public IAssetData GetPatchHelper<T>(T data, string? assetName = null)
+            where T : notnull
         {
             if (data == null)
                 throw new ArgumentNullException(nameof(data), "Can't get a patch helper for a null value.");
diff --git a/src/SMAPI/Framework/ModHelpers/DataHelper.cs b/src/SMAPI/Framework/ModHelpers/DataHelper.cs
index 86a34ee8..92b3b398 100644
--- a/src/SMAPI/Framework/ModHelpers/DataHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/DataHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -42,19 +40,21 @@ namespace StardewModdingAPI.Framework.ModHelpers
         ** JSON file
         ****/
         /// <inheritdoc />
-        public TModel ReadJsonFile<TModel>(string path) where TModel : class
+        public TModel? ReadJsonFile<TModel>(string path)
+            where TModel : class
         {
             if (!PathUtilities.IsSafeRelativePath(path))
                 throw new InvalidOperationException($"You must call {nameof(IModHelper.Data)}.{nameof(this.ReadJsonFile)} with a relative path.");
 
             path = Path.Combine(this.ModFolderPath, PathUtilities.NormalizePath(path));
-            return this.JsonHelper.ReadJsonFileIfExists(path, out TModel data)
+            return this.JsonHelper.ReadJsonFileIfExists(path, out TModel? data)
                 ? data
                 : null;
         }
 
         /// <inheritdoc />
-        public void WriteJsonFile<TModel>(string path, TModel data) where TModel : class
+        public void WriteJsonFile<TModel>(string path, TModel? data)
+            where TModel : class
         {
             if (!PathUtilities.IsSafeRelativePath(path))
                 throw new InvalidOperationException($"You must call {nameof(IMod.Helper)}.{nameof(IModHelper.Data)}.{nameof(this.WriteJsonFile)} with a relative path (without directory climbing).");
@@ -71,7 +71,8 @@ namespace StardewModdingAPI.Framework.ModHelpers
         ** Save file
         ****/
         /// <inheritdoc />
-        public TModel ReadSaveData<TModel>(string key) where TModel : class
+        public TModel? ReadSaveData<TModel>(string key)
+            where TModel : class
         {
             if (Context.LoadStage == LoadStage.None)
                 throw new InvalidOperationException($"Can't use {nameof(IMod.Helper)}.{nameof(IModHelper.Data)}.{nameof(this.ReadSaveData)} when a save file isn't loaded.");
@@ -82,14 +83,15 @@ namespace StardewModdingAPI.Framework.ModHelpers
             string internalKey = this.GetSaveFileKey(key);
             foreach (IDictionary<string, string> dataField in this.GetDataFields(Context.LoadStage))
             {
-                if (dataField.TryGetValue(internalKey, out string value))
+                if (dataField.TryGetValue(internalKey, out string? value))
                     return this.JsonHelper.Deserialize<TModel>(value);
             }
             return null;
         }
 
         /// <inheritdoc />
-        public void WriteSaveData<TModel>(string key, TModel model) where TModel : class
+        public void WriteSaveData<TModel>(string key, TModel? model)
+            where TModel : class
         {
             if (Context.LoadStage == LoadStage.None)
                 throw new InvalidOperationException($"Can't use {nameof(IMod.Helper)}.{nameof(IModHelper.Data)}.{nameof(this.WriteSaveData)} when a save file isn't loaded.");
@@ -97,7 +99,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
                 throw new InvalidOperationException($"Can't use {nameof(IMod.Helper)}.{nameof(IModHelper.Data)}.{nameof(this.WriteSaveData)} when connected to a remote host. (Save files are stored on the main player's computer.)");
 
             string internalKey = this.GetSaveFileKey(key);
-            string data = model != null
+            string? data = model != null
                 ? this.JsonHelper.Serialize(model, Formatting.None)
                 : null;
 
@@ -114,16 +116,18 @@ namespace StardewModdingAPI.Framework.ModHelpers
         ** Global app data
         ****/
         /// <inheritdoc />
-        public TModel ReadGlobalData<TModel>(string key) where TModel : class
+        public TModel? ReadGlobalData<TModel>(string key)
+            where TModel : class
         {
             string path = this.GetGlobalDataPath(key);
-            return this.JsonHelper.ReadJsonFileIfExists(path, out TModel data)
+            return this.JsonHelper.ReadJsonFileIfExists(path, out TModel? data)
                 ? data
                 : null;
         }
 
         /// <inheritdoc />
-        public void WriteGlobalData<TModel>(string key, TModel data) where TModel : class
+        public void WriteGlobalData<TModel>(string key, TModel? data)
+            where TModel : class
         {
             string path = this.GetGlobalDataPath(key);
             if (data != null)
diff --git a/src/SMAPI/Framework/ModHelpers/GameContentHelper.cs b/src/SMAPI/Framework/ModHelpers/GameContentHelper.cs
index 6d0c2f5f..4c1cde02 100644
--- a/src/SMAPI/Framework/ModHelpers/GameContentHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/GameContentHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Linq;
 using StardewModdingAPI.Framework.Content;
@@ -71,6 +69,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         public T Load<T>(string key)
+            where T : notnull
         {
             IAssetName assetName = this.ContentCore.ParseAssetName(key, allowLocales: true);
             return this.Load<T>(assetName);
@@ -78,6 +77,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         public T Load<T>(IAssetName assetName)
+            where T : notnull
         {
             try
             {
@@ -105,6 +105,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         public bool InvalidateCache<T>()
+            where T : notnull
         {
             this.Monitor.Log($"Requested cache invalidation for all assets of type {typeof(T)}. This is an expensive operation and should be avoided if possible.");
             return this.ContentCore.InvalidateCache((_, _, type) => typeof(T).IsAssignableFrom(type)).Any();
@@ -118,7 +119,8 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public IAssetData GetPatchHelper<T>(T data, string assetName = null)
+        public IAssetData GetPatchHelper<T>(T data, string? assetName = null)
+            where T : notnull
         {
             if (data == null)
                 throw new ArgumentNullException(nameof(data), "Can't get a patch helper for a null value.");
diff --git a/src/SMAPI/Framework/ModHelpers/ModContentHelper.cs b/src/SMAPI/Framework/ModHelpers/ModContentHelper.cs
index b149ed82..fc47f269 100644
--- a/src/SMAPI/Framework/ModHelpers/ModContentHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/ModContentHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using Microsoft.Xna.Framework.Content;
 using StardewModdingAPI.Framework.Content;
@@ -57,6 +55,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <inheritdoc />
         public T Load<T>(string relativePath)
+            where T : notnull
         {
             relativePath = this.RelativePathCache.GetAssetName(relativePath);
 
@@ -80,7 +79,8 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public IAssetData GetPatchHelper<T>(T data, string relativePath = null)
+        public IAssetData GetPatchHelper<T>(T data, string? relativePath = null)
+            where T : notnull
         {
             if (data == null)
                 throw new ArgumentNullException(nameof(data), "Can't get a patch helper for a null value.");
diff --git a/src/SMAPI/Framework/ModHelpers/ModRegistryHelper.cs b/src/SMAPI/Framework/ModHelpers/ModRegistryHelper.cs
index e277e6fa..84899610 100644
--- a/src/SMAPI/Framework/ModHelpers/ModRegistryHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/ModRegistryHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System.Collections.Generic;
 using StardewModdingAPI.Framework.Reflection;
 
@@ -47,7 +45,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public IModInfo Get(string uniqueID)
+        public IModInfo? Get(string uniqueID)
         {
             return this.Registry.Get(uniqueID);
         }
@@ -59,7 +57,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public object GetApi(string uniqueID)
+        public object? GetApi(string uniqueID)
         {
             // validate ready
             if (!this.Registry.AreAllModsInitialized)
@@ -69,17 +67,18 @@ namespace StardewModdingAPI.Framework.ModHelpers
             }
 
             // get raw API
-            IModMetadata mod = this.Registry.Get(uniqueID);
+            IModMetadata? mod = this.Registry.Get(uniqueID);
             if (mod?.Api != null && this.AccessedModApis.Add(mod.Manifest.UniqueID))
                 this.Monitor.Log($"Accessed mod-provided API for {mod.DisplayName}.");
             return mod?.Api;
         }
 
         /// <inheritdoc />
-        public TInterface GetApi<TInterface>(string uniqueID) where TInterface : class
+        public TInterface? GetApi<TInterface>(string uniqueID)
+            where TInterface : class
         {
             // get raw API
-            object api = this.GetApi(uniqueID);
+            object? api = this.GetApi(uniqueID);
             if (api == null)
                 return null;
 
diff --git a/src/SMAPI/Framework/ModHelpers/MultiplayerHelper.cs b/src/SMAPI/Framework/ModHelpers/MultiplayerHelper.cs
index 96b074e2..a419327e 100644
--- a/src/SMAPI/Framework/ModHelpers/MultiplayerHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/MultiplayerHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System.Collections.Generic;
 using StardewModdingAPI.Framework.Networking;
 using StardewValley;
@@ -41,9 +39,9 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public IMultiplayerPeer GetConnectedPlayer(long id)
+        public IMultiplayerPeer? GetConnectedPlayer(long id)
         {
-            return this.Multiplayer.Peers.TryGetValue(id, out MultiplayerPeer peer)
+            return this.Multiplayer.Peers.TryGetValue(id, out MultiplayerPeer? peer)
                 ? peer
                 : null;
         }
@@ -55,7 +53,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         }
 
         /// <inheritdoc />
-        public void SendMessage<TMessage>(TMessage message, string messageType, string[] modIDs = null, long[] playerIDs = null)
+        public void SendMessage<TMessage>(TMessage message, string messageType, string[]? modIDs = null, long[]? playerIDs = null)
         {
             this.Multiplayer.BroadcastModMessage(
                 message: message,
diff --git a/src/SMAPI/Framework/ModHelpers/ReflectionHelper.cs b/src/SMAPI/Framework/ModHelpers/ReflectionHelper.cs
index 24cbd01c..af018c87 100644
--- a/src/SMAPI/Framework/ModHelpers/ReflectionHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/ReflectionHelper.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Reflection;
 using StardewModdingAPI.Framework.Reflection;
@@ -39,7 +37,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         {
             return this.AssertAccessAllowed(
                 this.Reflector.GetField<TValue>(obj, name, required)
-            );
+            )!;
         }
 
         /// <inheritdoc />
@@ -47,7 +45,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         {
             return this.AssertAccessAllowed(
                 this.Reflector.GetField<TValue>(type, name, required)
-            );
+            )!;
         }
 
         /// <inheritdoc />
@@ -55,7 +53,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         {
             return this.AssertAccessAllowed(
                 this.Reflector.GetProperty<TValue>(obj, name, required)
-            );
+            )!;
         }
 
         /// <inheritdoc />
@@ -63,7 +61,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         {
             return this.AssertAccessAllowed(
                 this.Reflector.GetProperty<TValue>(type, name, required)
-            );
+            )!;
         }
 
         /// <inheritdoc />
@@ -71,7 +69,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         {
             return this.AssertAccessAllowed(
                 this.Reflector.GetMethod(obj, name, required)
-            );
+            )!;
         }
 
         /// <inheritdoc />
@@ -79,7 +77,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         {
             return this.AssertAccessAllowed(
                 this.Reflector.GetMethod(type, name, required)
-            );
+            )!;
         }
 
 
@@ -90,7 +88,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         /// <typeparam name="T">The field value type.</typeparam>
         /// <param name="field">The field being accessed.</param>
         /// <returns>Returns the same field instance for convenience.</returns>
-        private IReflectedField<T> AssertAccessAllowed<T>(IReflectedField<T> field)
+        private IReflectedField<T>? AssertAccessAllowed<T>(IReflectedField<T>? field)
         {
             this.AssertAccessAllowed(field?.FieldInfo);
             return field;
@@ -100,7 +98,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         /// <typeparam name="T">The property value type.</typeparam>
         /// <param name="property">The property being accessed.</param>
         /// <returns>Returns the same property instance for convenience.</returns>
-        private IReflectedProperty<T> AssertAccessAllowed<T>(IReflectedProperty<T> property)
+        private IReflectedProperty<T>? AssertAccessAllowed<T>(IReflectedProperty<T>? property)
         {
             this.AssertAccessAllowed(property?.PropertyInfo.GetMethod?.GetBaseDefinition());
             this.AssertAccessAllowed(property?.PropertyInfo.SetMethod?.GetBaseDefinition());
@@ -110,7 +108,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
         /// <summary>Assert that mods can use the reflection helper to access the given member.</summary>
         /// <param name="method">The method being accessed.</param>
         /// <returns>Returns the same method instance for convenience.</returns>
-        private IReflectedMethod AssertAccessAllowed(IReflectedMethod method)
+        private IReflectedMethod? AssertAccessAllowed(IReflectedMethod? method)
         {
             this.AssertAccessAllowed(method?.MethodInfo.GetBaseDefinition());
             return method;
@@ -118,18 +116,18 @@ namespace StardewModdingAPI.Framework.ModHelpers
 
         /// <summary>Assert that mods can use the reflection helper to access the given member.</summary>
         /// <param name="member">The member being accessed.</param>
-        private void AssertAccessAllowed(MemberInfo member)
+        private void AssertAccessAllowed(MemberInfo? member)
         {
             if (member == null)
                 return;
 
             // get type which defines the member
-            Type declaringType = member.DeclaringType;
+            Type? declaringType = member.DeclaringType;
             if (declaringType == null)
                 throw new InvalidOperationException($"Can't validate access to {member.MemberType} {member.Name} because it has no declaring type."); // should never happen
 
             // validate access
-            string rootNamespace = typeof(Program).Namespace;
+            string? rootNamespace = typeof(Program).Namespace;
             if (declaringType.Namespace == rootNamespace || declaringType.Namespace?.StartsWith(rootNamespace + ".") == true)
                 throw new InvalidOperationException($"SMAPI blocked access by {this.ModName} to its internals through the reflection API. Accessing the SMAPI internals is strongly discouraged since they're subject to change, which means the mod can break without warning. (Detected access to {declaringType.FullName}.{member.Name}.)");
         }