add accessed key to dictionary KeyNotFoundException message

3 files changed, 83 insertions, 0 deletions

diff --git a/src/SMAPI.Mods.ErrorHandler/ModEntry.cs b/src/SMAPI.Mods.ErrorHandler/ModEntry.cs
index d9426d75..719eddab 100644
--- a/src/SMAPI.Mods.ErrorHandler/ModEntry.cs
+++ b/src/SMAPI.Mods.ErrorHandler/ModEntry.cs
@@ -31,6 +31,7 @@ namespace StardewModdingAPI.Mods.ErrorHandler
             // apply patches
             new GamePatcher(this.Monitor).Apply(
                 new DialogueErrorPatch(monitorForGame, this.Helper.Reflection),
+                new DictionaryPatches(this.Helper.Reflection),
                 new EventPatches(monitorForGame),
                 new GameLocationPatches(monitorForGame),
                 new ObjectErrorPatch(),
diff --git a/src/SMAPI.Mods.ErrorHandler/Patches/DictionaryPatches.cs b/src/SMAPI.Mods.ErrorHandler/Patches/DictionaryPatches.cs
new file mode 100644
index 00000000..ce88999d
--- /dev/null
+++ b/src/SMAPI.Mods.ErrorHandler/Patches/DictionaryPatches.cs
@@ -0,0 +1,81 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using HarmonyLib;
+using StardewModdingAPI.Framework.Patching;
+using StardewValley.GameData;
+using StardewValley.GameData.HomeRenovations;
+using StardewValley.GameData.Movies;
+
+namespace StardewModdingAPI.Mods.ErrorHandler.Patches
+{
+    /// <summary>A Harmony patch for <see cref="Dictionary{TKey,TValue}"/> which adds the accessed key to <see cref="KeyNotFoundException"/> exceptions.</summary>
+    /// <remarks>Patch methods must be static for Harmony to work correctly. See the Harmony documentation before renaming patch arguments.</remarks>
+    [SuppressMessage("ReSharper", "InconsistentNaming", Justification = "Argument names are defined by Harmony and methods are named for clarity.")]
+    [SuppressMessage("ReSharper", "IdentifierTypo", Justification = "Argument names are defined by Harmony and methods are named for clarity.")]
+    internal class DictionaryPatches : IHarmonyPatch
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>Simplifies access to private code.</summary>
+        private static IReflectionHelper Reflection;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="reflector">Simplifies access to private code.</param>
+        public DictionaryPatches(IReflectionHelper reflector)
+        {
+            DictionaryPatches.Reflection = reflector;
+        }
+
+        /// <inheritdoc />
+        public void Apply(Harmony harmony)
+        {
+            Type[] keyTypes = { typeof(int), typeof(string) };
+            Type[] valueTypes = { typeof(int), typeof(string), typeof(HomeRenovation), typeof(MovieData), typeof(SpecialOrderData) };
+
+            foreach (Type keyType in keyTypes)
+            {
+                foreach (Type valueType in valueTypes)
+                {
+                    Type dictionaryType = typeof(Dictionary<,>).MakeGenericType(keyType, valueType);
+
+                    harmony.Patch(
+                        original: AccessTools.Method(dictionaryType, "get_Item"),
+                        finalizer: new HarmonyMethod(this.GetType(), nameof(DictionaryPatches.Finalize_GetItem))
+                    );
+                }
+            }
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>The method to call after the dictionary indexer throws an exception.</summary>
+        /// <param name="key">The dictionary key being fetched.</param>
+        /// <param name="__exception">The exception thrown by the wrapped method, if any.</param>
+        /// <returns>Returns the exception to throw, if any.</returns>
+        private static Exception Finalize_GetItem(object key, Exception __exception)
+        {
+            if (__exception is KeyNotFoundException)
+                AddKeyTo(__exception, key?.ToString());
+
+            return __exception;
+        }
+
+        /// <summary>Add the accessed key to an exception message.</summary>
+        /// <param name="exception">The exception to modify.</param>
+        /// <param name="key">The dictionary key.</param>
+        private static void AddKeyTo(Exception exception, string key)
+        {
+            DictionaryPatches.Reflection
+                .GetField<string>(exception, "_message")
+                .SetValue($"{exception.Message}\nkey: '{key}'");
+        }
+    }
+}
diff --git a/src/SMAPI.Mods.ErrorHandler/SMAPI.Mods.ErrorHandler.csproj b/src/SMAPI.Mods.ErrorHandler/SMAPI.Mods.ErrorHandler.csproj
index 006a09ca..531d3699 100644
--- a/src/SMAPI.Mods.ErrorHandler/SMAPI.Mods.ErrorHandler.csproj
+++ b/src/SMAPI.Mods.ErrorHandler/SMAPI.Mods.ErrorHandler.csproj
@@ -15,6 +15,7 @@
 
   <ItemGroup>
     <Reference Include="$(GameExecutableName)" HintPath="$(GamePath)\$(GameExecutableName).exe" Private="False" />
+    <Reference Include="StardewValley.GameData" HintPath="$(GamePath)\StardewValley.GameData.dll" Private="False" />
     <Reference Include="xTile" HintPath="$(GamePath)\xTile.dll" Private="False" />
   </ItemGroup>