feature: add support for private base type options (#288)

Resolves #287

Author: Alxandr

src/CommandLineUtils/Internal/ReflectionHelper.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
 using System.Reflection;
@@ -35,25 +36,25 @@ public static SetPropertyDelegate GetPropertySetter(PropertyInfo prop)
 
         public static MethodInfo[] GetPropertyOrMethod(Type type, string name)
         {
-            const BindingFlags binding = BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static;
-            return type.GetTypeInfo()
-                .GetMethods(binding)
+            var members = GetAllMembers(type.GetTypeInfo()).ToList();
+            return members
+                .OfType<MethodInfo>()
                 .Where(m => m.Name == name)
-                .Concat(type.GetTypeInfo().GetProperties(binding).Where(m => m.Name == name).Select(p => p.GetMethod))
+                .Concat(members.OfType<PropertyInfo>().Where(m => m.Name == name).Select(p => p.GetMethod))
                 .Where(m => m.ReturnType == typeof(string) && m.GetParameters().Length == 0)
                 .ToArray();
         }
 
         public static PropertyInfo[] GetProperties(Type type)
         {
-            const BindingFlags binding = BindingFlags.Instance | BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public;
-            return type.GetTypeInfo().GetProperties(binding);
+            return GetAllMembers(type.GetTypeInfo())
+                .OfType<PropertyInfo>()
+                .ToArray();
         }
 
         public static MemberInfo[] GetMembers(Type type)
         {
-            const BindingFlags binding = BindingFlags.Instance | BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public;
-            return type.GetTypeInfo().GetMembers(binding);
+            return GetAllMembers(type.GetTypeInfo()).ToArray();
         }
 
         public static object[] BindParameters(MethodInfo method, CommandLineApplication command, CancellationToken cancellationToken)
@@ -102,5 +103,21 @@ public static bool IsNullableType(TypeInfo typeInfo, out Type? wrappedType)
 
             return result;
         }
+
+        static IEnumerable<MemberInfo> GetAllMembers(TypeInfo typeInfo)
+        {
+            const BindingFlags binding = BindingFlags.Instance | BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.DeclaredOnly;
+
+            while (typeInfo != null) 
+            {
+                var members = typeInfo.GetMembers(binding);
+                foreach (var member in members)
+                {
+                    yield return member;
+                }
+
+                typeInfo = typeInfo.BaseType?.GetTypeInfo();
+            }
+        }
     }
 }

test/CommandLineUtils.Tests/OptionAttributeTests.cs

@@ -259,6 +259,25 @@ public void BindsToStaticPropertiesWithSetterMethod()
             Assert.Equal(2, PrivateSetterProgram.StaticValue);
         }
 
+        abstract class PrivateBaseType
+        {
+            [Option]
+            int Count { get; }
+
+            public int GetCount() => Count;
+        }
+
+        class WithPrivateBaseTypeApplication : PrivateBaseType
+        {
+        }
+
+        [Fact]
+        public void BindsToPrivateBaseTypeProperty()
+        {
+            var parsed = CommandLineParser.ParseArgs<WithPrivateBaseTypeApplication>("--count", "42");
+            Assert.Equal(42, parsed.GetCount());
+        }
+
         [Theory]
         [InlineData("Option123", "o", "option123", "OPTION123")]
         [InlineData("dWORD", "d", "d-word", "D_WORD")]