Hot Chocolate throws error when Flags Enum is in a paged response

[cabillin]

Product

Hot Chocolate

Version

15.1.3

Link to minimal reproduction

https://github.com/cabillin/hot-chocolate-issues/tree/flag_enum_incorrect_handling

Steps to reproduce

query bob {
  parents(first: 1) {
    nodes {
      childId
      id
      flags {
        isANA
      }
    }
  }
}

What is expected?

{
  "data": {
    "parents": {
      "nodes": [
        {
          "childId": "Child1",
          "id": 1,
          "flags": {
            "isANA": false
          }
        }
      ]
    }
  }
}

What is actually happening?

{
  "errors": [
    {
      "message": "Unexpected Execution Error",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "parents"
      ],
      "extensions": {
        "message": "Property 'Int32 Count' is not defined for type 'HotChocolate.Issues.Classes.FlagEnum' (Parameter 'property')",
        "stackTrace": "   at System.Linq.Expressions.Expression.Property(Expression expression, PropertyInfo property)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildAssignmentExpression(PropertyNode node, Context context)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildSelectionSetExpression(Context context, TypeNode parent)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildTypeSwitchExpression(Context context, TypeContainer parent)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildAssignmentExpression(PropertyNode node, Context context)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildSelectionSetExpression(Context context, TypeNode parent)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildTypeSwitchExpression(Context context, TypeContainer parent)\r\n   at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildExpression[TRoot](ISelection selection)\r\n   at HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensions.<>c__2`1.<GetOrCreateExpression>b__2_0(String _, ValueTuple`2 ctx)\r\n   at HotChocolate.Execution.Processing.Operation.GetOrAddState[TState,TContext](String key, Func`3 createState, TContext context)\r\n   at HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensions.GetOrCreateExpression[TValue](ISelection selection)\r\n   at HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensions.AsSelector[TValue](ISelection selection)\r\n   at HotChocolate.Data.QueryContextParameterExpressionBuilder.CreateQueryContext[T](IResolverContext context)\r\n   at lambda_method3(Closure, IResolverContext)\r\n   at HotChocolate.Types.Helpers.FieldMiddlewareCompiler.<>c__DisplayClass9_0.<<CreateResolverMiddleware>b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at HotChocolate.Types.UnwrapFieldMiddlewareHelper.<>c__DisplayClass0_1.<<CreateDataMiddleware>b__1>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at HotChocolate.Types.Pagination.PagingMiddleware.InvokeAsync(IMiddlewareContext context)\r\n   at HotChocolate.Execution.Processing.Tasks.ResolverTask.ExecuteResolverPipelineAsync(CancellationToken cancellationToken)\r\n   at HotChocolate.Execution.Processing.Tasks.ResolverTask.TryExecuteAsync(CancellationToken cancellationToken)"
      }
    }
  ],
  "data": {
    "parents": null
  }
}

Additional Context

query bob {
  parents(first: 1) {
    nodes {
      childId
      id
    }
  }
}

works

query bob {
  parents(first: 2, where: { flags: { eq: { isANA: true } } }) {
    nodes {
      childId
      id
    }
  }
}

returns successfully, but I'm not sure if it is working correctly. I would have expected to get back id 3 and id 5, but I only get back id 3

[cabillin]

following up

[cabillin]

@michaelstaib Can you team at least suggest a workaround? This is about to become a blocking issue for us.

[tobias-tengler]

Hey @cabillin :)
Sorry for the delay.

We've added support for flag enums a while back, but you need to opt in first:

services.AddGraphQLServer()
    .ModifyOptions(o => o.EnableFlagEnums = true)

This will turn your FlagEnum enum into an object type like this:

type FlagEnumFlags {
  isAna: Boolean!
  isBob: Boolean!
  # ...
}

and if used as an input into this:

input FlagEnumFlagsInput {
  isAna: Boolean
  isBob: Boolean
  # ...
}

Hope this helps! Feel free to re-open if this does not address your issue.

[cabillin]

Thanks! I am now getting the following error (not in the minimal repro, but in my actual code) when I try to include at least 1 value (e.g. isANA) in the query (including a filter of the enumFlag works fine):
extensions": {
"message": "Property 'Int32 Count' is not defined for type '{name of enum flag}' (Parameter 'property')",
"stackTrace": " at System.Linq.Expressions.Expression.Property(Expression expression, PropertyInfo property)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildAssignmentExpression(PropertyNode node, Context context)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildSelectionSetExpression(Context context, TypeNode parent)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildTypeSwitchExpression(Context context, TypeContainer parent)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildAssignmentExpression(PropertyNode node, Context context)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildSelectionSetExpression(Context context, TypeNode parent)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildTypeSwitchExpression(Context context, TypeContainer parent)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildAssignmentExpression(PropertyNode node, Context context)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildSelectionSetExpression(Context context, TypeNode parent)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildTypeSwitchExpression(Context context, TypeContainer parent)\r\n at HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildExpression[TRoot](ISelection selection)\r\n at HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensions.<>c__21.<GetOrCreateExpression>b__2_0(String _, ValueTuple2 ctx)\r\n at HotChocolate.Execution.Processing.Operation.GetOrAddState[TState,TContext](String key, Func`3 createState, TContext context)\r\n at HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensions.GetOrCreateExpression[TValue](ISelection selection)\r\n at HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensions.AsSelector[TValue](ISelection selection)\r\n at HotChocolate.Data.QueryContextParameterExpressionBuilder.CreateQueryContext[T](IResolverContext context)\r\n at lambda_method81(Closure, IResolverContext)\r\n at HotChocolate.Types.Helpers.FieldMiddlewareCompiler.<>c__DisplayClass9_0.<b__0>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n at HotChocolate.Types.UnwrapFieldMiddlewareHelper.<>c__DisplayClass0_1.<b__1>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n at HotChocolate.Types.Pagination.PagingMiddleware.InvokeAsync(IMiddlewareContext context)\r\n at HotChocolate.Execution.Processing.Tasks.ResolverTask.ExecuteResolverPipelineAsync(CancellationToken cancellationToken)\r\n at HotChocolate.Execution.Processing.Tasks.ResolverTask.TryExecuteAsync(CancellationToken cancellationToken)"
}

[cabillin]

@tobias-tengler I don't have permission to re-open the issue; could you do it for me? Thanks!

[cabillin]

I've updated the title, main question, and minimal reproduction to reflect the error I see once I set EnableFlagEnums to true

[cabillin]

following up

[cabillin]

@tobias-tengler , any update on this issue?