How to return multiple errors without data?

[kamilgregorczyk]

Hi everyone, I'm looking for a possibility of returning a list of errors in a proper graphqls way (without unions between success/failure responses).

I started using the example provided by the doc but the data field is required, not providing it or providing a null returns an additional error on graphql

DataFetcherResult.newResult<LoginResult>()
                .data(null)
                .error(
                    newErrorException()
                        .message("test message")
                        .build()
                ).build()
                ```
                

"The field at path '/login' was declared as a non null type, but the code involved in retrieving data has wrongly returned a null value.  The graphql specification requires that the parent field be set to null, or if that is non nullable that it bubble up null to its parent and so on. The non-nullable type is 'LoginResult' within parent type 'Mutation'",
      "path": [
        "login"
      ]

Is there any good way of returning just errors during mutations which don't require data structure? as I said, I managed to get it working via unions but I prefer a solution similar to DataFetcherResult

[dariuszkuc]

If the top level field is marked as non-nullable then attempting to return a null value is a critical error as it violates the type safety guarantee of the GraphQL. If you want to return null for your data you have to make those fields nullable.

[kamilgregorczyk]

The thing is I don't want to return any data at all, I'd like to return multiple errors to the caller in a graphqls way, when I throw an exception I get such structure:

{
  "errors": [
    {
      "message": "meessage",
      "locations": [
        {
          "line": 4,
          "column": 7
        }
      ],
      "path": [
        "login",
        "email"
      ]
    }
  ]
}

but this returns one error as only one exception was thrown, now instead of one item in the errors array I'd like to put multiple ones

[dariuszkuc]

You can return multiple errors but again your response has to be spec compatible - if you attempt to return null for non-nullable field it will fail validation which takes precedence and (most likely) removes all other errors.

[kamilgregorczyk]

so there is no way of returning error without data like it happens when an exception is thrown ?

[smyrick]

@kamilgregorczyk Try not setting data at all

DataFetcherResult.newResult<LoginResult>()
    .error(
        newErrorException()
            .message("test message")
            .build()
    ).build()

[kamilgregorczyk]

Yes, and I'm looking for a solution to return multiple errors without data and without any exceptions saying that my data Is missing :)

[smyrick]

The way to solve that would be to either: make the root field selection nullable so it is a valid response if you just return null or to not return a GraphQL response and instead throw an HTTP error.

[kamilgregorczyk]

Making fields nullable is not a good solution, also throwing and HTTP error will result in only one message.

I tried to find somewhere where expeditions are caught to maybe write my own processor for my own exception which could hold multiple messages but I couldn’t find anything that’s open for extension

[smyrick]

If you think that this behavior should be modified, it is handled in the underlying graphql-java library.

[kamilgregorczyk]

thanks, will go there for help