GraphQL.ExecutionError: Error trying to resolve - graphql

Question

Summary:
My GraphQL ExecuteAsync returns a result that contains. According to the stackTrace provided below, the system cannot resolve my custom type remitsGeneralSearch. The remitsGeneralSearch resolver can return a type called ClaimPaymentOrCheckSearchGraphType which is a UnionGraphType.
StackTrace:
["GraphQL.ExecutionError: Error trying to resolve remitsGeneralSearch.\n ---> System.InvalidOperationException: Unexpected type: \n at GraphQL.Execution.ExecutionStrategy.BuildExecutionNode(ExecutionNode parent, IGraphType graphType, Field field, FieldType fieldDefinition, String[] path)\n at GraphQL.Execution.ExecutionStrategy.SetSubFieldNodes(ExecutionContext context, ObjectExecutionNode parent, Dictionary`2 fields)\n at GraphQL.Execution.ExecutionStrategy.SetSubFieldNodes(ExecutionContext context, ObjectExecutionNode parent)\n at GraphQL.Execution.ExecutionStrategy.ExecuteNodeAsync(ExecutionContext context, ExecutionNode node)\n --- End of inner exception stack trace ---"]4008305)
GraphQL Version: 2.4.0
FrameWork: .Net
OS: MacOS Catalina
Links Referenced: https://github.com/graphql-dotnet/graphql-dotnet/issues/964
CODE SNIPPETS:
RESOLVER:
FieldAsync<ClaimPaymentOrCheckSearchGraphType>(
"remitsGeneralSearch",
resolve: async context =>
{
var securityFilter = await GetUserRemitFilters(context);
var range = context.GetRange();
var sortFields = context.GetArgument<List<SortField>>("sort") ?? Enumerable.Empty<SortField>();
var whereClaimPayment = context.GetArgument<ClaimPaymentSearchFilter>("whereClaimPayment");
Connection<ClaimPaymentSearchRow> claimPaymentSearchRowResult;
try
{
using (LogContext.PushProperty("where", whereClaimPayment, true))
{
//claimPaymentSearchRowResult = await DMAQueryService.GetRemitReadersAsync(context);
var whereArguments = context.Arguments["whereClaimPayment"] as Dictionary<string, object>;
claimPaymentSearchRowResult = await DMAQueryService.GetRemitReadersAsync(
range,
whereClaimPayment,
whereArguments,
sortFields,
securityFilter,
context.CancellationToken
);
}
}
catch (Exception e)
{
_logger.LogInformation("Exception occurred {e}", e);
throw e;
}
var userRemitFilters = context.UserContext as Services.DMA.UserRemitFilters;
if (claimPaymentSearchRowResult.EdgeCount > 0)
{
return claimPaymentSearchRowResult;
}
var _whereCheckSearch = context.GetArgument<CheckSearchFilter>("whereCheck");
try
{
Connection<CheckSearchRow> checkSearchRowResult;
using (LogContext.PushProperty("whereCheck", _whereCheckSearch, true))
{
checkSearchRowResult = await DMAQueryService.GetCheckReadersAsync(context);
return checkSearchRowResult;
}
}
catch (Exception e)
{
throw e;
}
},arguments: queryArguments
);
}
catch (Exception e)
{
throw e;
}
Custom GraphType:
[Transient]
public class ClaimPaymentOrCheckSearchGraphType : UnionGraphType
{
private readonly ILogger<ClaimPaymentOrCheckSearchGraphType> _logger;
public ClaimPaymentOrCheckSearchGraphType(
ILogger<ClaimPaymentOrCheckSearchGraphType> logger,
ConnectionGraphType<ClaimPaymentSearchGraphType> claimPaymentSearchGraphType,
ConnectionGraphType<CheckSearchGraphType> checkSearchGraphType
)
{
_logger = logger;
Type<ConnectionGraphType<ClaimPaymentSearchGraphType>>();
Type<ConnectionGraphType<CheckSearchGraphType>>();
ResolveType = obj =>
{
try
{
if (obj is Connection<ClaimPaymentSearchRow>)
{
return claimPaymentSearchGraphType;
}
if (obj is Connection<CheckSearchRow>)
{
return checkSearchGraphType;
}
throw new ArgumentOutOfRangeException($"Could not resolve graph type for {obj.GetType().Name}");
}
catch (Exception e)
{
_logger.LogInformation("ClaimPaymentOrCheckSearchGraphType Exception {e}: ", e);
throw e;
}
};
}
}

Answer 1

Link to answer found here: https://github.com/graphql-dotnet/graphql-dotnet/issues/2674Try replacing this:
Type<ConnectionGraphType<ClaimPaymentSearchGraphType>>();
Type<ConnectionGraphType<CheckSearchGraphType>>();
with this:
AddPossibleType(claimPaymentSearchGraphType);
AddPossibleType(checkSearchGraphType);
I'm thinking that if you're registering these types as transients, then the copy that gets registered to the schema initialization code is a different copy that gets returned from ResolveType. Because of that, its fields' ResolvedType properties was never set, and so null is passed into BuildExecutionNode for the graphType instead of a resolved type.
If the ResolveType method could return a type rather than an instance, there wouldn't be an issue, but unfortunately that's not the way it works. Or you could register the type as a singleton.