1 files changed, 37 insertions, 0 deletions
diff --git a/src/SMAPI/Framework/StateTracking/FieldWatchers/ImmutableCollectionWatcher.cs b/src/SMAPI/Framework/StateTracking/FieldWatchers/ImmutableCollectionWatcher.cs
new file mode 100644
index 00000000..30e6274f
--- /dev/null
+++ b/src/SMAPI/Framework/StateTracking/FieldWatchers/ImmutableCollectionWatcher.cs
@@ -0,0 +1,37 @@
+using System.Collections.Generic;
+
+namespace StardewModdingAPI.Framework.StateTracking.FieldWatchers
+{
+    /// <summary>A collection watcher which never changes.</summary>
+    /// <typeparam name="TValue">The value type within the collection.</typeparam>
+    internal class ImmutableCollectionWatcher<TValue> : BaseDisposableWatcher, ICollectionWatcher<TValue>
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>A singleton collection watcher instance.</summary>
+        public static ImmutableCollectionWatcher<TValue> Instance { get; } = new ImmutableCollectionWatcher<TValue>();
+
+        /// <summary>Whether the collection changed since the last reset.</summary>
+        public bool IsChanged { get; } = false;
+
+        /// <summary>The values added since the last reset.</summary>
+        public IEnumerable<TValue> Added { get; } = new TValue[0];
+
+        /// <summary>The values removed since the last reset.</summary>
+        public IEnumerable<TValue> Removed { get; } = new TValue[0];
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Update the current value if needed.</summary>
+        public void Update() { }
+
+        /// <summary>Set the current value as the baseline.</summary>
+        public void Reset() { }
+
+        /// <summary>Stop watching the field and release all references.</summary>
+        public override void Dispose() { }
+    }
+}