Union error: "variable '....' of type '....' referenced from scope '', but it is not defined" about entitygraphql

[bzbetty]

oh interesting, my error seems to be due to not wrapping the sample app in a namespace - that's really confusing!

[bzbetty]

i have a feeling the implementation doesn't like only querying for a single type, in the method MakeSelectWithDynamicType i defaulted back to the old code is validTypes < 2. Was for a mix of performance/safety reasons but I clearly missed this case.

Can you try add a second fragment type ?

[Eli-Black-Work]

@bzbetty Oooo, indeed, adding a second fragment type to the query makes the error go away! 🙂

[Eli-Black-Work]

That being said, when there are two fragments, the requested fields don't seem to be returned.

Code

public interface IUser { }

public class Employee : IUser
{
    public string Name { get; set; }
}

public class Owner : IUser
{
    public string Id { get; set; }
}

public class UsersContext : IUsersContext
{
    public List<IUser> Users { get; set; } = new()
    {
        new Employee
        {
            Name = "test employee"
        },
        new Owner
        {
            Id = "1111"
        }
    };
}

public interface IUsersContext
{
    public List<IUser> Users { get; }
}

public class Program
{
    public static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);

        builder.Services.AddCors();
        builder.Services.AddTransient<IUsersContext, UsersContext>();
        builder.Services.AddGraphQLSchema<IUsersContext>(options =>
        {
            options.AutoBuildSchemaFromContext = false;

            options.ConfigureSchema = (schema) =>
            {
                schema.AddUnion<IUser>("User", null);
                schema.Type<IUser>().AddAllPossibleTypes();

                schema.UpdateQuery(queryType =>
                {
                    queryType.ReplaceField(
                        "users",
                        db => db.Users,
                        null
                    );
                });
            };
        });

        var app = builder.Build();
        app.UseHttpsRedirection();
        app.UseRouting();
        app.UseCors(builder =>
        {
            builder
            .WithOrigins("*")
            .WithMethods("POST")
            .AllowAnyHeader();
        });
        app.UseEndpoints(endpoints => endpoints.MapGraphQL<IUsersContext>());
        app.Run();
    }
}

Query

{ users { ... on Employee { name } ... on Owner { id } } }

Result

{"data":{"users":[{},{}]}}

[bzbetty]

what happens if you also ask for typename?

{ __typename users { ... on Employee { name } ... on Owner { id } } }

[bzbetty]

Have a look at TestAutoUnion seems to be a basic working sample?
I thought I'd used Unions in my codebase somehwere, i'll have a dig tomorrow.

[bzbetty]

Actually is this the same field vs property serialization issue you had in #263 ?

[lukemurray]

Shouldn't be the serialisation issue if running the above code as that is using the AddGraphQLSchema extensions which sets that up.

[Eli-Black-Work]

@bzbetty If I ask for typename, I get it back correctly.

Query

{
  users {
    __typename,
    ... on Employee { name },
    ... on Owner { id }
  }
}

Result

{
  "data": {
    "users": [
      {
        "__typename": "Employee"
      },
      {
        "__typename": "Owner"
      }
    ]
  }
}

[Eli-Black-Work]

@bzbetty I thought this might be a field serialization issue, too (since indeed, I just messed that up, haha 😆), but as @lukemurray says, in this example, I'm using AddGraphQLSchema().

[bzbetty]

What version are you running against? if I use your sample app against 4.0.1 i get quiet a different error

[Eli-Black-Work]

@bzbetty I'm running against commit 099aad8 🙂

[bzbetty]

If I do the following instead of passing the query via http it seems to return the value correctly.

                    var gql = new GraphQLCompiler(schema).Compile(@"
query {
   users {
      __typename
     ... on Employee { name },
    ... on Owner { id }
   }
}");
                    var context = new UsersContext();

                    var qr = gql.ExecuteQuery(context, null, null);
                    int i = 0;

[bzbetty]

with a breakpoint in DefaultGraphQLResponseSerializer i can confirm the data is on the object, it's just not serialized for some reason.

[bzbetty]

potentially related dotnet/runtime#31742

[bzbetty]

also this https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/polymorphism?pivots=dotnet-6-0 - although I'm not seeing a fix

[Eli-Black-Work]

oh interesting, my error seems to be due to not wrapping the sample app in a namespace - that's really confusing!

Lol, that's surprising! 😆

[Eli-Black-Work]

@bzbetty Very interesting... and unexpected! 🙂

I guess in our case, the solution is simple: Use the Newtonsoft serializer, which is actually what we're using anyway... I just used the System.Json serializer in the example, since that lead to a shorter repro.

I does look like .NET 7 supports polymorphic serialization, but... ya... that'd required apps to be running .NET 7: https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/polymorphism?pivots=dotnet-7-0

It look like we uncovered three bugs within this thread, haha.

[Eli-Black-Work]

BTW, I can confirm that this works fine when using the Newtonsoft serializer 🙂

[lukemurray]

@Bosch-Eli-Black would you mind double checking against the master branch? Want to make sure there is not an edge case we have missed. Thanks

[Eli-Black-Work]

@lukemurray I'm afraid that made it a bit worse, haha 😄

Code

using EntityGraphQL.AspNet;

namespace Example;

public interface IUser { }

public class Employee : IUser
{
    public string Name { get; set; }
}

public class Owner : IUser
{
    public string Id { get; set; }
}

public class UsersContext : IUsersContext
{
    public List<IUser> Users { get; set; } = new()
    {
        new Employee
        {
            Name = "test employee"
        },
        new Owner
        {
            Id = "1111"
        }
    };
}

public interface IUsersContext
{
    public List<IUser> Users { get; }
}

public class Program
{
    public static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);

        builder.Services.AddCors();
        builder.Services.AddTransient<IUsersContext, UsersContext>();
        builder.Services.AddGraphQLSchema<IUsersContext>(options =>
        {
            options.AutoBuildSchemaFromContext = false;

            options.ConfigureSchema = (schema) =>
            {
                schema.AddUnion<IUser>("User", null);
                schema.Type<IUser>().AddAllPossibleTypes();

                schema.UpdateQuery(queryType =>
                {
                    queryType.ReplaceField(
                        "users",
                        db => db.Users,
                        null
                    );
                });
            };
        });

        var app = builder.Build();
        app.UseHttpsRedirection();
        app.UseRouting();
        app.UseCors(builder =>
        {
            builder
            .WithOrigins("*")
            .WithMethods("POST")
            .AllowAnyHeader();
        });
        app.UseEndpoints(endpoints => endpoints.MapGraphQL<IUsersContext>());
        app.Run();
    }
}

Query

{ users { __typename, ... on Employee { name } ... on Owner { id } } }

Result

[
    {
        "key": "data",
        "value": [
            {
                "key": "users",
                "value": [
                    {},
                    {}
                ]
            }
        ]
    }
]

Tested with d65435f

[bzbetty]

PR should now return

{
  "data": {
    "users": [
      {
        "name": "test employee",
        "__typename": "Employee"
      },
      {
        "id": "1111",
        "__typename": "Owner"
      }
    ]
  }
}

[Eli-Black-Work]

@bzbetty Thanks!

Will test tomorrow, God willing 🙂

[Eli-Black-Work]

@bzbetty and @lukemurray It works! Thank you! ^_^

I've confirmed that both bugs that were discovered in this issue have been fixed 🙂

• #264 (comment)
• #264 (comment)

Thanks again! 🙂