1094 Allow overriding of CLI actions through a new attribute

Engine.UnitTests/CliCommandTest.cs

@@ -25,8 +25,36 @@ public void CliActionTreeTest()
             Assert.IsTrue(root.GetSubCommand("test action testaction".Split(' ')).Name == "testaction");
             Assert.IsTrue(root.GetSubCommand("test action testaction arg".Split(' ')).Name == "testaction");
         }
+
+        [Test]
+        public void CliOverrideActionTest()
+        {
+            var tree = new CliActionTree();
+            Assert.IsNull(tree.GetSubCommand(new string[] {"TestGroup", "TestAction"}));
+            Assert.AreEqual("TestAction", tree.GetSubCommand(new string[] { "TestGroup1", "TestAction" }).Name);
+        }
     }
 
+    [Display("TestAction", Group: "TestGroup")]
+    public class DefaultTestAction : ICliAction
+    {
+        public int Execute(CancellationToken cancellationToken)
+        {
+            throw new NotImplementedException();
+        }
+    }
+
+    [Display("TestAction", Group: "TestGroup1")]
+    [OverrideCliAction(typeof(DefaultTestAction))]
+    public class DefaultTestAction1 : ICliAction
+    {
+        public int Execute(CancellationToken cancellationToken)
+        {
+            throw new NotImplementedException();
+        }
+    }
+
+
     [Display("testaction", Groups: new[] { "test", "action" }, Description:"Runs TestAction")]
     public class TestAction : ICliAction
     {

Engine/Cli/CliActionExecutor.cs

@@ -31,13 +31,25 @@ public CliActionTree()
                 .Where(t => t.CanCreateInstance && t.GetDisplayAttribute() != null).ToList();
             Name = "tap";
             Root = this;
+
+            HashSet<ITypeData> overridenTypes = commands.Where(c => c.HasAttribute<OverrideCliActionAttribute>())
+                .Select(c => TypeData.FromType(c.GetAttribute<OverrideCliActionAttribute>().OverrideType))
+                .Cast<ITypeData>()
+                .ToHashSet();
+
             foreach (var item in commands)
-                ParseCommand(item, item.GetDisplayAttribute().Group, Root);
+            {
+                if (!overridenTypes.Contains(item))
+                {
+                    ParseCommand(item, item.GetDisplayAttribute().Group, Root);
+                }
+            }
         }
 
         CliActionTree(CliActionTree parent, string name)
         {
             Name = name;
+            Root = parent.Root;
         }
 
         private static void ParseCommand(ITypeData type, string[] group, CliActionTree command)
@@ -111,6 +123,31 @@ internal int GetMaxCommandTreeLength(int levelPadding)
         }
     }
 
+    /// <summary>
+    /// Used to override a CLI action with a new CLI action.
+    /// Adding this attribute, removes the old CLI action, and adds a new one in its place.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class)]
+    public class OverrideCliActionAttribute : Attribute
+    {
+        /// <summary>
+        /// The type to override.
+        /// </summary>
+        public Type OverrideType { get; set; }
+
+        /// <summary>
+        /// Used to override a CLI action with a new CLI action.
+        /// Adding this attribute, removes the old CLI action, and adds a new one in its place.
+        /// </summary>
+        /// <param name="overrideType">
+        /// The type to override.
+        /// </param>
+        public OverrideCliActionAttribute(Type overrideType)
+        {
+            OverrideType = overrideType;
+        }
+    }
+
     /// <summary>
     /// Helper used to execute <see cref="ICliAction"/>s.
     /// </summary>

Engine/Reflection/ReflectionDataExtensions.cs

@@ -97,7 +97,7 @@ public static bool DescendsTo(this ITypeData type, Type basetype)
         }
 
         /// <summary>
-        /// Returns true if a reflection ifno has an attribute of type T.
+        /// Returns true if a reflection info has an attribute of type T.
         /// </summary>
         /// <typeparam name="T"></typeparam>
         /// <param name="mem"></param>