entc/gen: add support for referencing fks to existing fields (#1289)

examples/o2m2types/ent/migrate/schema.go

@@ -25,9 +25,8 @@ var (
 		PrimaryKey: []*schema.Column{PetsColumns[0]},
 		ForeignKeys: []*schema.ForeignKey{
 			{
-				Symbol:  "pets_users_pets",
-				Columns: []*schema.Column{PetsColumns[2]},
-
+				Symbol:     "pets_users_pets",
+				Columns:    []*schema.Column{PetsColumns[2]},
 				RefColumns: []*schema.Column{UsersColumns[0]},
 				OnDelete:   schema.SetNull,
 			},

examples/o2m2types/ent/pet_query.go

@@ -381,7 +381,8 @@ func (pq *PetQuery) sqlAll(ctx context.Context) ([]*Pet, error) {
 		ids := make([]int, 0, len(nodes))
 		nodeids := make(map[int][]*Pet)
 		for i := range nodes {
-			if fk := nodes[i].user_pets; fk != nil {
+			fk := nodes[i].user_pets
+			if fk != nil {
 				ids = append(ids, *fk)
 				nodeids[*fk] = append(nodeids[*fk], nodes[i])
 			}