enable nullable annotations for most of the SMAPI toolkit (#837)

3 files changed, 20 insertions, 15 deletions

diff --git a/src/SMAPI.Toolkit/Utilities/EnvironmentUtility.cs b/src/SMAPI.Toolkit/Utilities/EnvironmentUtility.cs
index f14678be..1791c5b3 100644
--- a/src/SMAPI.Toolkit/Utilities/EnvironmentUtility.cs
+++ b/src/SMAPI.Toolkit/Utilities/EnvironmentUtility.cs
@@ -1,7 +1,4 @@
-#nullable disable
-
 using System;
-using System.Diagnostics.CodeAnalysis;
 using StardewModdingAPI.Toolkit.Framework;
 
 namespace StardewModdingAPI.Toolkit.Utilities
@@ -36,7 +33,6 @@ namespace StardewModdingAPI.Toolkit.Utilities
 
         /// <summary>Get the human-readable OS name and version.</summary>
         /// <param name="platform">The current platform.</param>
-        [SuppressMessage("ReSharper", "EmptyGeneralCatchClause", Justification = "Error suppressed deliberately to fallback to default behaviour.")]
         public static string GetFriendlyPlatformName(Platform platform)
         {
             return LowLevelEnvironmentUtility.GetFriendlyPlatformName(platform.ToString());
diff --git a/src/SMAPI.Toolkit/Utilities/FileUtilities.cs b/src/SMAPI.Toolkit/Utilities/FileUtilities.cs
index ba2d0f47..a6bf5929 100644
--- a/src/SMAPI.Toolkit/Utilities/FileUtilities.cs
+++ b/src/SMAPI.Toolkit/Utilities/FileUtilities.cs
@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.IO;
 using System.Security.Cryptography;
diff --git a/src/SMAPI.Toolkit/Utilities/PathUtilities.cs b/src/SMAPI.Toolkit/Utilities/PathUtilities.cs
index d035d4cd..9b7a78a0 100644
--- a/src/SMAPI.Toolkit/Utilities/PathUtilities.cs
+++ b/src/SMAPI.Toolkit/Utilities/PathUtilities.cs
@@ -1,6 +1,5 @@
-#nullable disable
-
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.IO;
 using System.Linq;
@@ -38,8 +37,11 @@ namespace StardewModdingAPI.Toolkit.Utilities
         /// <param name="path">The path to split.</param>
         /// <param name="limit">The number of segments to match. Any additional segments will be merged into the last returned part.</param>
         [Pure]
-        public static string[] GetSegments(string path, int? limit = null)
+        public static string[] GetSegments(string? path, int? limit = null)
         {
+            if (path == null)
+                return Array.Empty<string>();
+
             return limit.HasValue
                 ? path.Split(PathUtilities.PossiblePathSeparators, limit.Value, StringSplitOptions.RemoveEmptyEntries)
                 : path.Split(PathUtilities.PossiblePathSeparators, StringSplitOptions.RemoveEmptyEntries);
@@ -47,8 +49,14 @@ namespace StardewModdingAPI.Toolkit.Utilities
 
         /// <summary>Normalize an asset name to match how MonoGame's content APIs would normalize and cache it.</summary>
         /// <param name="assetName">The asset name to normalize.</param>
-        public static string NormalizeAssetName(string assetName)
+        [Pure]
+        [return: NotNullIfNotNull("assetName")]
+        public static string? NormalizeAssetName(string? assetName)
         {
+            assetName = assetName?.Trim();
+            if (string.IsNullOrEmpty(assetName))
+                return assetName;
+
             return string.Join(PathUtilities.PreferredAssetSeparator.ToString(), PathUtilities.GetSegments(assetName)); // based on MonoGame's ContentManager.Load<T> logic
         }
 
@@ -56,7 +64,8 @@ namespace StardewModdingAPI.Toolkit.Utilities
         /// <param name="path">The file path to normalize.</param>
         /// <remarks>This should only be used for file paths. For asset names, use <see cref="NormalizeAssetName"/> instead.</remarks>
         [Pure]
-        public static string NormalizePath(string path)
+        [return: NotNullIfNotNull("path")]
+        public static string? NormalizePath(string? path)
         {
             path = path?.Trim();
             if (string.IsNullOrEmpty(path))
@@ -80,7 +89,7 @@ namespace StardewModdingAPI.Toolkit.Utilities
             }
 
             // keep trailing separator
-            if ((!hasRoot || segments.Any()) && PathUtilities.PossiblePathSeparators.Contains(path[path.Length - 1]))
+            if ((!hasRoot || segments.Any()) && PathUtilities.PossiblePathSeparators.Contains(path[^1]))
                 newPath += PathUtilities.PreferredPathSeparator;
 
             return newPath;
@@ -98,7 +107,7 @@ namespace StardewModdingAPI.Toolkit.Utilities
         /// <summary>Get whether a path is relative and doesn't try to climb out of its containing folder (e.g. doesn't contain <c>../</c>).</summary>
         /// <param name="path">The path to check.</param>
         [Pure]
-        public static bool IsSafeRelativePath(string path)
+        public static bool IsSafeRelativePath(string? path)
         {
             if (string.IsNullOrWhiteSpace(path))
                 return true;
@@ -111,9 +120,11 @@ namespace StardewModdingAPI.Toolkit.Utilities
         /// <summary>Get whether a string is a valid 'slug', containing only basic characters that are safe in all contexts (e.g. filenames, URLs, etc).</summary>
         /// <param name="str">The string to check.</param>
         [Pure]
-        public static bool IsSlug(string str)
+        public static bool IsSlug(string? str)
         {
-            return !Regex.IsMatch(str, "[^a-z0-9_.-]", RegexOptions.IgnoreCase);
+            return
+                string.IsNullOrWhiteSpace(str)
+                || !Regex.IsMatch(str, "[^a-z0-9_.-]", RegexOptions.IgnoreCase);
         }
     }
 }