Corax static index returns incorrect results when paging a filtered query sorted by ISO date strings #23570

using Raven.Client.Documents.Indexes;
using Raven.TestDriver;
using Xunit;

public class CoraxSortedPagingTest : RavenTestDriver
{
    private sealed class Item
    {
        public string Id { get; set; } = default!;
        public string Category { get; set; } = default!;
        public string Date { get; set; } = default!;
        public string Name { get; set; } = default!;
    }

    private sealed class Items_ByCategory : AbstractIndexCreationTask<Item>
    {
        public Items_ByCategory()
        {
            Map = items => from item in items
                           select new { item.Category, item.Date };
        }
    }

    [Fact]
    public async Task Should_page_after_sorting_complete_terms()
    {
        using var store = GetDocumentStore();
        await new Items_ByCategory().ExecuteAsync(store);

        using (var session = store.OpenAsyncSession())
        {
            await session.StoreAsync(new Item { Id = "items/A", Name = "A", Category = "News", Date = "2026-09-01" });
            await session.StoreAsync(new Item { Id = "items/B", Name = "B", Category = "News", Date = "2026-08-01" });
            await session.StoreAsync(new Item { Id = "items/C", Name = "C", Category = "News", Date = "2026-07-01" });
            await session.StoreAsync(new Item { Id = "items/D", Name = "D", Category = "News", Date = "2026-06-01" });
            await session.SaveChangesAsync();
        }

        WaitForIndexing(store);

        using var querySession = store.OpenAsyncSession();
        var page = await querySession.Query<Item, Items_ByCategory>()
            .Where(item => item.Category == "News")
            .OrderByDescending(item => item.Date)
            .Take(2)
            .ToListAsync();

        Assert.Equal(new[] { "A", "B" }, page.Select(item => item.Name));
    }
}