@requires does not work as expected for Apollo Federation

[mihirpmehta]

What happened?

When i entity in on subgraph which does have @requires from another subgraph entity, Resolvers does not generated where i can access the required attribute from another subgraph

What did you expect?

func (r *queryResolver) Screen(ctx context.Context, id string) (*model.GuideScreen, error) {
	return FindScreen(id)
}

this method should be generated with asset input

Minimal graphql.schema and models to reproduce

Subgraph1

type GuideScreen @key(fields: "id")  {
  id:ID!
  tile:Tile!
}

type Asset @key(fields: "channelID", resolvable: false) {
  channelID: ID!
  movie_title: String! @external
}

type Tile @key(fields: "id") {
  id: ID!
  title: String! @requires(fields: "asset { movie_title }")
  asset: Asset
}

Subgraph2

type Asset @key(fields: "channelID") {
  channelID:ID!
  movie_title: String!
}

versions

• v0.17.29
• go1.20.3?

In federation.go i can see

func (ec *executionContext) __resolve_entities(ctx context.Context, representations []map[string]interface{}) []fedruntime.Entity {
switch typeName {

.....

			case "findTileByID":
				id0, err := ec.unmarshalNID2string(ctx, rep["id"])
				if err != nil {
					return fmt.Errorf(`unmarshalling param 0 for findTileByID(): %w`, err)
				}
				entity, err := ec.resolvers.Entity().FindTileByID(ctx, id0)
				if err != nil {
					return fmt.Errorf(`resolving Entity "Tile": %w`, err)
				}

				entity.Asset.MovieTitle, err = ec.unmarshalNString2string(ctx, rep["asset"].(map[string]interface{})["movie_title"])
				if err != nil {
					return err
				}
				list[idx[i]] = entity
				return nil
			}

		}
		return fmt.Errorf("%w: %s", ErrUnknownType, typeName)

Thank you

[mihirpmehta]

Update

Somehow router skips calling subgraph 2 before calling subgraph1 and throwing error

interface conversion: interface {} is nil, not map[string]interface {}

type Entity @key(fields: "id") {
  id: ID!
  independentString: String
  otherEntity: Other 
  dependentString: String @requires(fields: "OtherEntity { supplementaryString }")
}

type OtherEntity @key(fields: "id") {
  id: ID!
  supplementaryString: String @external
}

Subgraph2

type Other @key(fields: "id") {
  id: ID!
  supplementaryString: String
}

When we generate boilerplate and implement schema resolver and entity resolver for both subgraph. Somehow subgraph2 never gets called from router. and tries to fetch directly from Subgraph1

[DRodriguez88]

@mihirpmehta what was the solution here? I'm having the same issue.

gqlgen 0.17.43
go 1.22

[mihirpmehta]

They have comeup with a solution
go mod edit -replace github.com/99designs/gqlgen=github.com/99designs/gqlgen@15cef76f18afec4c5352911360e33f4042500697

#2884 (comment) (I have not tried this yet)