Federation entity resolver generation

[nhibberd]

A combination of #1388 & #1429

What happened?

{Entity}Resolver's are not generated (example example/federation/reviews/graph/schema.resolvers.go) without specifying an explicit custom model (e.g. example/federation/reviews/graph/model/models.go)

Replication in the examples:

cd example/federation/reviews
rm graph/model/models.go
go generate server.go

validation failed: packages.Load: gqlgen/example/federation/reviews/graph/schema.resolvers.go:38:40: ProductResolver not declared by package generated
gqlgen/example/federation/reviews/graph/schema.resolvers.go:41:37: UserResolver not declared by package generated

exit status 3

What did you expect?

I expected that generated Entitys would also generate the EntityResolver's? Is this not the case by design?

Minimal graphql.schema and models to reproduce

type Review {
    body: String!
}

extend type User @key(fields: "id") {
    id: ID! @external
    reviews: [Review]
}

versions

• gqlgen version? v0.13.0
• go version? 1.14
• dep or go modules?

Notes

Looking into the code a little more, I assume the issue is arising from codegen/config/config.go - Init()

[nhibberd]

Workaround for anyone else who comes across this:

Add a custom model for the type for the entity being extended, in this example User

package model

type User struct {
	ID string `json:"id"`
}

func (User) IsEntity() {}

And the model to the config - autobind

autobind: []
  - "mymodel/model"

[MichaelJCompton]

Yep, looks like this doesn't quite work correctly without a custom model.

The work around (use custom models) is annoying, but looks like it generates the correct code and isn't functionally different.

[MichaelJCompton]

Actually, looks like it's specifically to do with the fields generated in the model

extend type Product @key(fields: "upc") {
    upc: String! @external
    reviews: [Review]
}

Won't work with a model like

type Product struct {
	Upc        string    `json:"upc"`
	Reviews []*Review `json:"reviews"`
}

The Review field means that the ProductResolver doesn't get generated.

[genesor]

Another solution to have the resolvers without a custom model is to force them in the gqlgen.yml file.

models:
  User:
    fields:
      reviews:
        resolver: true
  Product:
    fields:
      reviews:
        resolver: true