Exist basic scalar type in downloaded schema and got Schema errors

[sonatard]

Question

When I download the Schema with gradlew :app:downloadApolloSchema , the basic scalar type(ID, Int, Float...) exists in Schema file. Probably because of this, Android Studio is throwing an error, but how should I deal with this?

There is no problem with the operation such as building or sending requests.

Also, I sometimes write code to parse GraphQL schemas in Go, but I get the same error there and cannot parse it. Should the Go GraphQL parser be made not to throw an error, or should the schema not include a basic scalar type, which is correct?

[martinbonnin]

Hi 👋 . This is a known issue in the GraphQL IntelliJ plugin. These types needs to be in the schema because there exists several versions of them (deprecated input fields, repeated directives, etc... have been introduced more recently). And we need to know what version is used to do proper validation.

[sonatard]

Thank you! How does knowing the version affect the parser?

[martinbonnin]

It's affecting validation and/or introspection. Take the latest builtin __InputValue type definition:

type __InputValue {
  name: String!
  description: String
  type: __Type!
  defaultValue: String
  isDeprecated: Boolean!
  deprecationReason: String
}

And write this query:

{
  __schema {
    types {
      inputFields {
        isDeprecated
      }
    }
  }
}

It will validate well for Apollo Kotlin because isDeprecated is in the schema. Now if you try to execute this against an older version of the spec that doesn't know about deprecated input fields, this query will error all the time. This is what we want to avoid by validating the queries client side.

[sonatard]

I see! I didn't know that 'isDeprecated' was missing from old spec Introspection's __InputValue.

Thank you for the detailed explanation.

[sonatard]

When representing a GraphQL schema using the type system definition language, all built-in scalars must be omitted for brevity.
https://spec.graphql.org/draft/#sec-Scalars.Built-in-Scalars

@martinbonnin Hi! I found this section in GraphQL Draft spec.
It seems to me that built-in scalars should not exist in the schema file. What do you think?

[martinbonnin]

Good catch, TIL! I'll remove them. It's only about builtin scalars though, not the introspection types or directives so there will be still some warnings for the time being but @BoD added a fix to the IntelliJ plugin there

[martinbonnin]

PR here

[sonatard]

Thanks 👍

[martinbonnin]

@sonatard: for the record, I opened this PR in the GraphQL spec to explicit how introspection types should be handled in SDL. The tldr; is that it's not easy and will probably require to change to introspection and how servers declare their capabilities to other tools. You can read more in yesterday's working group meeting notes