Add support for QueryContext with mutation conventions

[glen-84]

Product

Hot Chocolate

Is your feature request related to a problem?

// Mutation conventions enabled ...
public static async Task<User?> RegisterUser(
    RegisterUserInput input,
    QueryContext<User> query,
    IMediator mediator,
    CancellationToken cancellationToken)
{
    var (isSuccess, userId, errors) = await mediator.Send(
        new RegisterUserCommand(input.Username, input.EmailAddress),
        cancellationToken);

    return isSuccess
        ? await mediator.Send(new GetUserByIdQuery(userId, query), cancellationToken)
        : throw new AggregateException(errors.ToDomainExceptions());
}

  message: The selection set is empty.
  stackTrace: "   at
    HotChocolate.Execution.Projections.SelectionExpressionBuilder.BuildExpr\
    ession[TRoot](ISelection selection)\r

    \   at
    HotChocolate.Execution.Processing.HotChocolateExecutionSelectionExtensi\
    ons.<>c__2`1.<GetOrCreateExpression>b__2_0(String _, ValueTuple`2 ctx)\r

    \   at
    HotChocolate.Execution.Processing.Operation.GetOrAddState[TState,TConte\
    xt](String key, Func`3 createState, TContext context)\r

The solution you'd like

Add support for QueryContext with mutation conventions.

[glen-84]

Workaround:

public static async Task<User?> RegisterUser(
    RegisterUserInput input,
    IResolverContext context,
    IMediator mediator,
    CancellationToken cancellationToken)
{
    var (isSuccess, userId, errors) = await mediator.Send(
        new RegisterUserCommand(input.Username, input.EmailAddress),
        cancellationToken);

    var selector = context.Select("user").FirstOrDefault()?.AsSelector<User>();
    var query = new QueryContext<User>(selector);

    return isSuccess
        ? await mediator.Send(new GetUserByIdQuery(userId, query), cancellationToken)
        : throw new AggregateException(errors.ToDomainExceptions());
}