Consistently resolve ignore flags in derived types

src/GraphQL.Conventions/Types/Resolution/ObjectReflector.cs

@@ -250,17 +250,27 @@ private IEnumerable<GraphFieldInfo> GetFields(TypeInfo typeInfo)
                 .ImplementedInterfaces
                 .SelectMany(iface => iface.GetMethods(DefaultBindingFlags));
 
-            return typeInfo
+            var fields = typeInfo
                 .GetMethods(DefaultBindingFlags)
                 .Union(implementedMethods)
                 .Union(GetExtensionMethods(typeInfo))
                 .Where(IsValidMember)
                 .Where(methodInfo => !methodInfo.IsSpecialName)
                 .Cast<MemberInfo>()
-                .Union(properties)
-                .Select(DeriveField)
+                .Union(properties);
+
+            var deduped = fields
+                .GroupBy(prop => prop.Name)
+                .Select(g => g.First());
+
+            var derivedFields = deduped
+                .Select(DeriveField);
+
+            var filteredFields = derivedFields
                 .Where(field => !field.IsIgnored)
                 .OrderBy(field => field.Name);
+
+            return filteredFields;
         }
 
         private IEnumerable<GraphArgumentInfo> GetArguments(MethodInfo methodInfo)

test/GraphQL.Conventions.Tests/Attributes/MetaData/IgnoreAttributeTests.cs

@@ -1,4 +1,8 @@
+using System.Linq;
 using GraphQL.Conventions;
+using GraphQL.Conventions.Adapters;
+using GraphQL.Conventions.Builders;
+using GraphQL.Types;
 using Tests.Templates;
 using Tests.Templates.Extensions;
 // ReSharper disable UnusedMember.Local
@@ -24,6 +28,44 @@ public void Enum_Members_Can_Be_Ignored()
             type.ShouldHaveFieldWithName("DEPRECATED_MEMBER").AndWithDeprecationReason("Some enum member reason");
         }
 
+        [Test]
+        public void Derived_Fields_Can_Be_Ignored()
+        {
+            var type = TypeInfo<Implementation>();
+            type.Fields.Count.ShouldEqual(2);
+            type.ShouldHaveFieldWithName("firstProperty");
+            type.ShouldHaveFieldWithName("someOtherProperty");
+            type.ShouldNotHaveFieldWithName("someProperty");
+
+            var iface = TypeInfo<ISomeInterface>();
+            iface.Fields.Count.ShouldEqual(1);
+            iface.ShouldHaveFieldWithName("firstProperty");
+            iface.ShouldNotHaveFieldWithName("someProperty");
+        }
+
+        [Test]
+        public void Can_Ignore_Unwanted_Fields_On_Derived_Types()
+        {
+            var schema = new SchemaConstructor<ISchema, IGraphType>(new GraphTypeAdapter())
+                .IgnoreTypes((t, m) => m?.Name == nameof(ISomeInterfaceExternal.SomeProperty))
+                .Build(typeof(SchemaType));
+
+            schema.Initialize();
+            var type = schema.AllTypes[nameof(ImplementationExternal)] as ObjectGraphType;
+            Assert.AreEqual(1, type.Fields.Count(f => f.Name == "someOtherProperty"));
+            Assert.AreEqual(0, type.Fields.Count(f => f.Name == "someProperty"));
+        }
+
+        private class SchemaType
+        {
+            public QueryType Query { get; }
+        }
+
+        private class QueryType
+        {
+            public ImplementationExternal Foo => new();
+        }
+
         private class FieldData
         {
             public int NormalField { get; set; }
@@ -42,5 +84,39 @@ public enum Enum
                 DeprecatedMember,
             }
         }
+
+        private class Implementation : ISomeInterface
+        {
+            public string FirstProperty { get; set; }
+
+            [Ignore]
+            public string SomeProperty { get; set; }
+
+            public string SomeOtherProperty { get; set; }
+        }
+
+        private interface ISomeInterface
+        {
+            public string FirstProperty { get; set; }
+
+            [Ignore]
+            public string SomeProperty { get; set; }
+        }
+
+        private class ImplementationExternal : ISomeInterfaceExternal
+        {
+            public string FirstProperty { get; set; }
+
+            public string SomeProperty { get; set; }
+
+            public string SomeOtherProperty { get; set; }
+        }
+
+        private interface ISomeInterfaceExternal
+        {
+            public string FirstProperty { get; set; }
+
+            public string SomeProperty { get; set; }
+        }
     }
 }