Fix #1704: handle @required nested fields as in @key (#1706)

entity resolver tests for nested @requires fields

plugin/federation/federation.gotpl

@@ -97,7 +97,7 @@ func (ec *executionContext) __resolve_entities(ctx context.Context, representati
 				}
 
 				{{ range .Requires }}
-					entity.{{.Field.JoinGo `.`}}, err = ec.{{.Type.UnmarshalFunc}}(ctx, rep["{{.Name}}"])
+					entity.{{.Field.JoinGo `.`}}, err = ec.{{.Type.UnmarshalFunc}}(ctx, rep["{{.Field.Join `"].(map[string]interface{})["`}}"])
 					if err != nil {
 						return err
 					}

plugin/federation/federation_entityresolver_test.go

@@ -231,6 +231,47 @@ func TestEntityResolver(t *testing.T) {
 		require.Equal(t, resp.Entities[1].Name, "mars")
 		require.Equal(t, resp.Entities[1].Diameter, 10)
 	})
+
+	t.Run("PlanetRequiresNested entities with requires directive having nested field", func(t *testing.T) {
+		representations := []map[string]interface{}{
+			{
+				"__typename": "PlanetRequiresNested",
+				"name":       "earth",
+				"world": map[string]interface{}{
+					"foo": "A",
+				},
+			}, {
+				"__typename": "PlanetRequiresNested",
+				"name":       "mars",
+				"world": map[string]interface{}{
+					"foo": "B",
+				},
+			},
+		}
+
+		var resp struct {
+			Entities []struct {
+				Name  string `json:"name"`
+				World struct {
+					Foo string `json:"foo"`
+				} `json:"world"`
+			} `json:"_entities"`
+		}
+
+		err := c.Post(
+			entityQuery([]string{
+				"PlanetRequiresNested {name, world { foo }}",
+			}),
+			&resp,
+			client.Var("representations", representations),
+		)
+
+		require.NoError(t, err)
+		require.Equal(t, resp.Entities[0].Name, "earth")
+		require.Equal(t, resp.Entities[0].World.Foo, "A")
+		require.Equal(t, resp.Entities[1].Name, "mars")
+		require.Equal(t, resp.Entities[1].World.Foo, "B")
+	})
 }
 
 func TestMultiEntityResolver(t *testing.T) {

plugin/federation/testdata/entityresolver/entity.resolvers.go

@@ -50,6 +50,26 @@ func (r *entityResolver) FindPlanetRequiresByName(ctx context.Context, name stri
 	}, nil
 }
 
+func (r *entityResolver) FindPlanetRequiresNestedByName(ctx context.Context, name string) (*generated.PlanetRequiresNested, error) {
+	worlds := map[string]*generated.World{
+		"earth": {
+			Foo: "A",
+		},
+		"mars": {
+			Foo: "B",
+		},
+	}
+	world, ok := worlds[name]
+	if !ok {
+		return nil, fmt.Errorf("unknown planet: %s", name)
+	}
+
+	return &generated.PlanetRequiresNested{
+		Name:  name,
+		World: world,
+	}, nil
+}
+
 func (r *entityResolver) FindWorldByHelloNameAndFoo(ctx context.Context, helloName string, foo string) (*generated.World, error) {
 	return &generated.World{
 		Hello: &generated.Hello{