.

Author: SimonCropp

src/GraphQL.EntityFramework/GraphApi/EfGraphQLService_Navigation.cs

@@ -81,7 +81,7 @@ public FieldBuilder<TSource, TReturn> AddNavigationField<TSource, TReturn, TProj
 
         // Store projection expression - flows through to Select expression builder
         IncludeAppender.SetProjectionMetadata(field, projection, typeof(TSource));
-        // Also set include metadata as fallback for cases where projection processing doesn't find navigations
+        // Also set include metadata as fallback for abstract types where projection can't be built
         var includeNames = FilterProjectionAnalyzer.ExtractRequiredProperties(projection);
         IncludeAppender.SetIncludeMetadata(field, name, includeNames);
 
@@ -151,7 +151,7 @@ public FieldBuilder<TSource, TReturn> AddNavigationField<TSource, TReturn>(
 
         // Store projection expression - flows through to Select expression builder
         IncludeAppender.SetProjectionMetadata(field, projection, typeof(TSource));
-        // Also set include metadata as fallback
+        // Also set include metadata as fallback for abstract types where projection can't be built
         var includeNames = FilterProjectionAnalyzer.ExtractRequiredProperties(projection);
         IncludeAppender.SetIncludeMetadata(field, name, includeNames);
 

src/GraphQL.EntityFramework/GraphApi/EfGraphQLService_NavigationConnection.cs

@@ -131,6 +131,8 @@ public ConnectionBuilder<TSource> AddNavigationConnectionField<TSource, TReturn>
         }
     }
 
+    // Use via reflection
+    // ReSharper disable once UnusedMember.Local
     ConnectionBuilder<TSource> AddEnumerableConnection<TSource, TGraph, TReturn>(
         ComplexGraphType<TSource> graph,
         string name,
@@ -206,6 +208,8 @@ ConnectionBuilder<TSource> AddEnumerableConnection<TSource, TGraph, TReturn>(
         return builder;
     }
 
+    // Use via reflection
+    // ReSharper disable once UnusedMember.Local
     ConnectionBuilder<TSource> AddEnumerableConnectionWithProjection<TSource, TGraph, TReturn, TProjection>(
         ComplexGraphType<TSource> graph,
         string name,
@@ -219,7 +223,7 @@ ConnectionBuilder<TSource> AddEnumerableConnectionWithProjection<TSource, TGraph
 
         // Store projection expression - flows through to Select expression builder
         IncludeAppender.SetProjectionMetadata(builder.FieldType, projection, typeof(TSource));
-        // Also set include metadata as fallback
+        // Also set include metadata as fallback for abstract types where projection can't be built
         var includeNames = FilterProjectionAnalyzer.ExtractRequiredProperties(projection);
         IncludeAppender.SetIncludeMetadata(builder.FieldType, name, includeNames);
 
@@ -294,6 +298,8 @@ ConnectionBuilder<TSource> AddEnumerableConnectionWithProjection<TSource, TGraph
         return builder;
     }
 
+    // Use via reflection
+    // ReSharper disable once UnusedMember.Local
     ConnectionBuilder<TSource> AddEnumerableConnectionWithProjectionOnly<TSource, TGraph, TReturn>(
         ComplexGraphType<TSource> graph,
         string name,
@@ -306,10 +312,13 @@ ConnectionBuilder<TSource> AddEnumerableConnectionWithProjectionOnly<TSource, TG
 
         // Store projection expression - flows through to Select expression builder
         IncludeAppender.SetProjectionMetadata(builder.FieldType, projection, typeof(TSource));
-        // Also set include metadata as fallback
+        // Also set include metadata as fallback for abstract types where projection can't be built
         var includeNames = FilterProjectionAnalyzer.ExtractRequiredProperties(projection);
         IncludeAppender.SetIncludeMetadata(builder.FieldType, name, includeNames);
 
+        // No resolver set - this overload is for interface types where the concrete types provide resolvers
+        // The projection metadata flows through to the Select expression builder
+
         var hasId = keyNames.ContainsKey(typeof(TReturn));
 
         //TODO: works around https://github.com/graphql-dotnet/graphql-dotnet/pull/2581/
@@ -319,4 +328,4 @@ ConnectionBuilder<TSource> AddEnumerableConnectionWithProjectionOnly<TSource, TG
         field.AddWhereArgument(hasId);
         return builder;
     }
-}
+}

src/GraphQL.EntityFramework/GraphApi/EfGraphQLService_NavigationList.cs

@@ -71,7 +71,7 @@ public FieldBuilder<TSource, TReturn> AddNavigationListField<TSource, TReturn, T
 
         // Store projection expression - flows through to Select expression builder
         IncludeAppender.SetProjectionMetadata(field, projection, typeof(TSource));
-        // Also set include metadata as fallback
+        // Also set include metadata as fallback for abstract types where projection can't be built
         var includeNames = FilterProjectionAnalyzer.ExtractRequiredProperties(projection);
         IncludeAppender.SetIncludeMetadata(field, name, includeNames);
 
@@ -131,7 +131,7 @@ public FieldBuilder<TSource, TReturn> AddNavigationListField<TSource, TReturn>(
 
         // Store projection expression - flows through to Select expression builder
         IncludeAppender.SetProjectionMetadata(field, projection, typeof(TSource));
-        // Also set include metadata as fallback
+        // Also set include metadata as fallback for abstract types where projection can't be built
         var includeNames = FilterProjectionAnalyzer.ExtractRequiredProperties(projection);
         IncludeAppender.SetIncludeMetadata(field, name, includeNames);
 

src/GraphQL.EntityFramework/GraphApi/EfGraphQLService_QueryableConnection.cs

@@ -118,6 +118,8 @@ public ConnectionBuilder<TSource> AddQueryConnectionField<TSource, TReturn>(
         }
     }
 
+    // Use via reflection
+    // ReSharper disable once UnusedMember.Local
     ConnectionBuilder<TSource> AddQueryableConnection<TSource, TGraph, TReturn>(
         IComplexGraphType graph,
         string name,

src/GraphQL.EntityFramework/IncludeAppender.cs

@@ -140,14 +140,15 @@ void ProcessProjectionField(
                 navigationProperties,
                 navProjections,
                 context);
-            // Only return if we added navigations; otherwise fall through to check field name
+            // Only return if we added navigations; otherwise fall through to include metadata
+            // This handles cases like abstract types where projection can't be built
             if (navProjections.Count > countBefore)
             {
                 return;
             }
         }
 
-        // Check if this field has include metadata (legacy approach)
+        // Check if this field has include metadata (fallback for abstract types, or legacy/obsolete approach)
         if (TryGetIncludeMetadata(fieldInfo.FieldType, out var includeNames))
         {
             // It's a navigation field - include ALL navigation properties from metadata

src/GraphQL.EntityFramework/Where/TypeConverter.cs

@@ -104,6 +104,8 @@ static IList ConvertStringsToListInternal(IEnumerable<string> values, Type type)
     static MethodInfo enumListMethod = typeof(TypeConverter)
         .GetMethod("GetEnumList", BindingFlags.Static | BindingFlags.NonPublic)!;
 
+    // Use via reflection
+    // ReSharper disable once UnusedMember.Local
     static List<T> GetEnumList<T>(IEnumerable<string> values)
         where T : struct
     {
@@ -119,6 +121,8 @@ static List<T> GetEnumList<T>(IEnumerable<string> values)
     static MethodInfo nullableEnumListMethod = typeof(TypeConverter)
         .GetMethod("GetNullableEnumList", BindingFlags.Static | BindingFlags.NonPublic)!;
 
+    // Use via reflection
+    // ReSharper disable once UnusedMember.Local
     static List<T?> GetNullableEnumList<T>(IEnumerable<string> values)
         where T : struct
     {