RavenDB Bug

Tests.cs

using System.Linq;
using Raven.Client.Embedded;
using Raven.Client.Indexes;
using Xunit;

namespace RavenTests
{
    public class Tests
    {
        [Fact]
        public void TestOrderByName()
        {
            // This test passes.

            var documentStore = new EmbeddableDocumentStore { RunInMemory = true };
            documentStore.Initialize();
            IndexCreation.CreateIndexes(GetType().Assembly, documentStore);

            using (var session = documentStore.OpenSession())
            {
                var foo = new Foo {Id = "foos/1", Names = new[] {"Alice", "Bob"}};
                session.Store(foo);
                session.SaveChanges();
            }

            using (var session = documentStore.OpenSession())
            {
                var results = session.Query<Foos_ByName.Result, Foos_ByName>()
                    .Customize(x => x.WaitForNonStaleResults())
                    .OrderBy(x => x.Name)
                    .ToList();

                Assert.NotNull(results);
                Assert.Equal(2, results.Count);
                
                Assert.Equal("foos/1", results[0].Id);
                Assert.Equal("Alice", results[0].Name);

                Assert.Equal("foos/1", results[1].Id);
                Assert.Equal("Bob", results[1].Name);
            }
        }

        [Fact]
        public void TestOrderById()
        {
            // This test fails with the following error:
            //
            //     The field '__document_id' is not indexed, cannot sort on fields that are not indexed
            //
            // It would appear that sort=Id is geting translated to sort=__document_id on the client side.
            // If I do the identical query in Raven Studio, sorting by Id, it works fine.

            var documentStore = new EmbeddableDocumentStore { RunInMemory = true };
            documentStore.Initialize();
            IndexCreation.CreateIndexes(GetType().Assembly, documentStore);

            using (var session = documentStore.OpenSession())
            {
                var foo = new Foo { Id = "foos/1", Names = new[] { "Alice", "Bob" } };
                session.Store(foo);
                session.SaveChanges();
            }

            using (var session = documentStore.OpenSession())
            {
                var results = session.Query<Foos_ByName.Result, Foos_ByName>()
                    .Customize(x => x.WaitForNonStaleResults())
                    .OrderBy(x => x.Id)  // This is the only difference from the passing test
                    .ToList();

                Assert.NotNull(results);
                Assert.Equal(2, results.Count);

                Assert.Equal("foos/1", results[0].Id);
                Assert.Equal("Alice", results[0].Name);

                Assert.Equal("foos/1", results[1].Id);
                Assert.Equal("Bob", results[1].Name);
            }
        }
    }

    public class Foo
    {
        public string Id { get; set; }
        public string[] Names { get; set; }
    }

    public class Foos_ByName : AbstractIndexCreationTask<Foo, Foos_ByName.Result>
    {
        public class Result
        {
            public string Id { get; set; }
            public string Name { get; set; }
        }

        public Foos_ByName()
        {
            Map = foos => from foo in foos
                          from name in foo.Names
                          select new
                              {
                                  foo.Id,
                                  Name = name
                              };

            // I shouldn't even need this since there's no reduction happening.
            // Without it the index does not build properly!  Why?  Is this a bug, or by design?
            Reduce = results => from result in results
                                group result by result
                                into g
                                select new
                                    {
                                        g.Key.Id,
                                        g.Key.Name
                                    };
        }
    }
}

Correction, I had the wrong grouping in the reduce step (result singular, not results plural). Doesn't change the issue.