Add Equality comparer for InstalledPackage

StabilityMatrix.Core/Helper/PropertyComparer.cs

@@ -0,0 +1,24 @@
+namespace StabilityMatrix.Core.Helper;
+
+public class PropertyComparer<T> : IEqualityComparer<T> where T : class
+{
+    private Func<T, object> Expr { get; set; }
+    
+    public PropertyComparer(Func<T, object> expr)
+    {
+        Expr = expr;
+    }
+    public bool Equals(T? x, T? y)
+    {
+        if (x == null || y == null) return false;
+        
+        var first = Expr.Invoke(x);
+        var second = Expr.Invoke(y);
+        
+        return first.Equals(second);
+    }
+    public int GetHashCode(T obj)
+    {
+        return obj.GetHashCode();
+    }
+}

StabilityMatrix.Core/Models/InstalledPackage.cs

@@ -158,6 +158,9 @@ public class InstalledPackage
         LibraryPath = System.IO.Path.Combine("Packages", packageFolderName);
     }
 
+    public static IEqualityComparer<InstalledPackage> Comparer { get; } =
+        new PropertyComparer<InstalledPackage>(p => p.Id);
+    
     protected bool Equals(InstalledPackage other)
     {
         return Id.Equals(other.Id);