feat(validation): use the existing errors array as context.Result, in…

[rune-vikestad]

Summary

We found that many of our application errors masked as EXEC_INVALID_LEAF_VALUE with the message Boolean cannot serialize the given value..

I eventually found that for all affected mutations we always hit the validator, but never the resolver. This lead me to look closer at the validation middleware, which I found was swallowing the original errors and replacing them with the magic string "errors".

I eventually found that the root cause of this was one of our AbstractValidator's, where a RuleFor failed. However, the validation middleware currently only replaces the original error with the magic string "errors"

Fixed

In 90.3.4 and earlier you'd find the following line in Dolittle.Vanir.Backend.GraphQL.Validation.ValidationMiddleware.cs

var errors = new List<IError>();
...
context.result = errors;
...

However, in 90.3.5 this suddenly changed to;

var errors = new List<IError>();
....
context.result = "errors";
....

Notice the new value of context.Result.

This is obviously not intended, as you can't magically set a string on a GraphQL result, and expect it to serialize correctly.

[jakhog]

@rune-vikestad, we merged this fix in #269. I couldn't figure out how to build this PR from a remote repository, and we had some issues with the build pipelines that we needed to sort out. But this change is now released as v12.0.1. (There are no breaking changes in C#, but TS and C# are versioned together).

Thanks a lot for the fix :)