Graphql-code-generator: [fragment-matcher] Error of missing directives when using `federation: true`

[mikestaub]

Describe the bug
I cannot generate the fragments when using federation.

To Reproduce
https://codesandbox.io/embed/graphql-codegen-issue-template-z5t3q

Expected behavior
Should run without errors.

[dotansimha]

@mikestaub why do you pass federation: true to fragment-matcher? It's not a valid option there.

Federation is a backend feature, and you should use it with typescript-resolvers only, and use it in your Federation backend.

[dotansimha]

@kamilkisiela and @ardatan noticed a different issue, some types are skipped and not being generated by fragment-matcher.

[ardatan]

@mikestaub fragment-matcher generates introspection data only for unions and interfaces. You don't have any of those.

[mikestaub]

@dotansimha I am passing federation: true to fragment-matcher because if I don't I get this error: Unknown directive "key".

As a workaround, I am simply including this file in the schema list field:

scalar _Any
scalar _FieldSet

# a union of all types that use the @key directive
union _Entity = Asset | Product | User | UserGroup

type _Service {
  sdl: String
}

extend type Query {
  _entities(representations: [_Any!]!): [_Entity]!
  _service: _Service!
}

directive @external on FIELD_DEFINITION
directive @requires(fields: _FieldSet!) on FIELD_DEFINITION
directive @provides(fields: _FieldSet!) on FIELD_DEFINITION
directive @key(fields: _FieldSet!) on OBJECT | INTERFACE

As defined here: https://www.apollographql.com/docs/apollo-server/federation/federation-spec/

Do you have an example of the fragment-matcher working with a federated schema?

[dotansimha]

Thanks @mikestaub . You are right.
At the moment, you can add those manually (add another item for schema field) and it will workaround this issue for your.
Me and @ardatan are thinking about doing a core change in the codegen that might fix that.

[jasmo2]

I am getting the Error even after set the workaround:
Couldn't find type Page in any of the schemas.
and the schema is:

extend type Page @key(fields: "id") {
  id: ID! @external
}

[mikestaub]

You must add your custom types to the union like you see above:

union _Entity = Asset | Product | User | UserGroup | Page

[jasmo2]

Here is my Polyfill

# import * from "../types-generators/schema.graphql"

scalar _Any
scalar _FieldSet

# a union of all types that use the @key directive
union _Entity = Page

type _Service {
  sdl: String
}

extend type Query {
  _entities(representations: [_Any!]!): [_Entity]!
  _service: _Service!
}

directive @external on FIELD_DEFINITION
directive @requires(fields: _FieldSet!) on FIELD_DEFINITION
directive @provides(fields: _FieldSet!) on FIELD_DEFINITION
directive @key(fields: _FieldSet!) on OBJECT | INTERFACE

# this is an optional directive discussed below
directive @extends on OBJECT

[mikestaub]

Are you sure there is a type Page { ... } in your schema?

[jasmo2]

Page is part of another federated project which is connected with this one, through the gateway.

[kamilkisiela]

2508 should handle that

[ardatan]

Does this issue still persist?

[dotansimha]

Fixed in v1.10.0.