fix some map tilesheets not editable if not playing in English

docs/release-notes.md

@@ -8,6 +8,7 @@
 * For modders:
   * Reloading a map asset will now update affected locations.
   * Reloading the `Data\NPCDispositions` asset will now update affected NPCs.
+  * Fixed some map tilesheets not editable if not playing in English.
   * Fixed newlines in most manifest fields not being ignored.
 
 * For the web UI:

src/SMAPI/Framework/ContentManagers/BaseContentManager.cs

@@ -32,12 +32,12 @@ namespace StardewModdingAPI.Framework.ContentManagers
         /// <summary>Whether the content coordinator has been disposed.</summary>
         private bool IsDisposed;
 
-        /// <summary>The language enum values indexed by locale code.</summary>
-        private readonly IDictionary<string, LanguageCode> LanguageCodes;
-
         /// <summary>A callback to invoke when the content manager is being disposed.</summary>
         private readonly Action<BaseContentManager> OnDisposing;
 
+        /// <summary>The language enum values indexed by locale code.</summary>
+        protected IDictionary<string, LanguageCode> LanguageCodes { get; }
+
 
         /*********
         ** Accessors

src/SMAPI/Framework/ContentManagers/GameContentManager.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
 using StardewModdingAPI.Framework.Content;
+using StardewModdingAPI.Framework.Exceptions;
 using StardewModdingAPI.Framework.Reflection;
 using StardewModdingAPI.Framework.Utilities;
 using StardewValley;
@@ -52,7 +53,10 @@ namespace StardewModdingAPI.Framework.ContentManagers
         /// <param name="language">The language code for which to load content.</param>
         public override T Load<T>(string assetName, LanguageCode language)
         {
+            // normalise asset name
             assetName = this.AssertAndNormaliseAssetName(assetName);
+            if (this.TryParseExplicitLanguageAssetKey(assetName, out string newAssetName, out LanguageCode newLanguage))
+                return this.Load<T>(newAssetName, newLanguage);
 
             // get from cache
             if (this.IsLoaded(assetName))
@@ -124,6 +128,29 @@ namespace StardewModdingAPI.Framework.ContentManagers
             return false;
         }
 
+        /// <summary>Parse an asset key that contains an explicit language into its asset name and language, if applicable.</summary>
+        /// <param name="rawAsset">The asset key to parse.</param>
+        /// <param name="assetName">The asset name without the language code.</param>
+        /// <param name="language">The language code removed from the asset name.</param>
+        private bool TryParseExplicitLanguageAssetKey(string rawAsset, out string assetName, out LanguageCode language)
+        {
+            if (string.IsNullOrWhiteSpace(rawAsset))
+                throw new SContentLoadException("The asset key is empty.");
+
+            // extract language code
+            int splitIndex = rawAsset.LastIndexOf('.');
+            if (splitIndex != -1 && this.LanguageCodes.TryGetValue(rawAsset.Substring(splitIndex + 1), out language))
+            {
+                assetName = rawAsset.Substring(0, splitIndex);
+                return true;
+            }
+
+            // no explicit language code found
+            assetName = rawAsset;
+            language = this.Language;
+            return false;
+        }
+
         /// <summary>Load the initial asset from the registered <see cref="Loaders"/>.</summary>
         /// <param name="info">The basic asset metadata.</param>
         /// <returns>Returns the loaded asset metadata, or <c>null</c> if no loader matched.</returns>