[typescript-resolvers] typesPrefix not applied to FederationTypes reference in FederationReferenceTypes

[dilaroga]

Which packages are impacted by your issue?

@graphql-codegen/typescript-resolvers

Describe the bug

When using typesPrefix: "I" (or any prefix) with federation: true, the generated
FederationReferenceTypes type references FederationTypes without the configured prefix,
causing a TypeScript compilation error.

The generated code defines IFederationTypes (with prefix) but references it as
FederationTypes (without prefix) inside IFederationReferenceTypes.

Your Example Website or App

N/A

Steps to Reproduce the Bug or Issue

codegen.yml:
schema: src/api/graphql/schema.graphql
generates:
  src/api/graphql/types.ts:
    plugins:
      - typescript
      - typescript-resolvers
    config:
      typesPrefix: I
      federation: true

schema.graphql (minimal example with federation):

type Query {
  _service: _Service!
}

type _Service {
  sdl: String
}

type Channel @key(fields: "id") {
  id: ID!
}

Run codegen and compile with TypeScript.

Actual behavior:

The generated code uses FederationTypes (without prefix) in the reference:

export type IFederationTypes = ResolversObject<{
  Channel: IChannel;
}>;

export type IFederationReferenceTypes = ResolversObject<{
  Channel:
    ( { __typename: 'Channel' }
    & GraphQLRecursivePick<FederationTypes['Channel'], {"id":true}> );  // ❌ Missing "I" prefix
}>;

TypeScript error:
error TS2552: Cannot find name 'FederationTypes'. Did you mean 'IFederationTypes'?

Expected behavior

The generated code should use IFederationTypes consistently:

  export type IFederationTypes = ResolversObject<{
    Channel: IChannel;
  }>;

  export type IFederationReferenceTypes = ResolversObject<{
    Channel:
      ( { __typename: 'Channel' }
      & GraphQLRecursivePick<IFederationTypes['Channel'], {"id":true}> );
  }>;

Screenshots or Videos

No response

Platform

OS: macOS / Linux
@graphql-codegen/cli: 6.1.1
@graphql-codegen/typescript-resolvers: 5.0.0 - 5.1.5 (all 5.x versions affected)
Node.js: 20.x / 22.x

Codegen Config File

schema: src/api/graphql/schema.graphql
generates:
  src/api/graphql/types.ts:
    plugins:
      - typescript
      - typescript-resolvers
    config:
      typesPrefix: I
      federation: true

Additional context

Versions tested

| vers. | Bug present |
| 4.5.2 | ❌ No (no FederationTypes generated) |
| 5.0.0 | ✅ Yes |
| 5.0.1 | ✅ Yes |
| 5.1.0 | ✅ Yes |
| 5.1.3 | ✅ Yes |
| 5.1.4 | ✅ Yes |
| 5.1.5 | ✅ Yes |

Potential fix location

The bug appears to be in packages/plugins/typescript/resolvers/src/visitor.ts.

In the buildFederationReferenceTypes() method, the type declaration name correctly uses
this.convertName('FederationReferenceTypes'), but the referenceSelectionSetsString
contains a hardcoded reference to FederationTypes:

& GraphQLRecursivePick<FederationTypes['Channel'], {"id":true}>

The fix should apply this.convertName('FederationTypes') when building
referenceSelectionSetsString, so it becomes:

& GraphQLRecursivePick<IFederationTypes['Channel'], {"id":true}>

The issue is likely in the code that constructs referenceSelectionSetsString - it should
use the naming convention when referencing FederationTypes.

Workaround

Pin @graphql-codegen/typescript-resolvers to ^4.5.2 until this is fixed.