entc/gen: restructure hooks execution (#741)

Closed #739

entc/integration/json/ent/user_create.go

@@ -68,14 +68,14 @@ func (uc *UserCreate) Mutation() *UserMutation {
 
 // Save creates the User in the database.
 func (uc *UserCreate) Save(ctx context.Context) (*User, error) {
-	if err := uc.preSave(); err != nil {
-		return nil, err
-	}
 	var (
 		err  error
 		node *User
 	)
 	if len(uc.hooks) == 0 {
+		if err = uc.check(); err != nil {
+			return nil, err
+		}
 		node, err = uc.sqlSave(ctx)
 	} else {
 		var mut Mutator = MutateFunc(func(ctx context.Context, m Mutation) (Value, error) {
@@ -83,6 +83,9 @@ func (uc *UserCreate) Save(ctx context.Context) (*User, error) {
 			if !ok {
 				return nil, fmt.Errorf("unexpected mutation type %T", m)
 			}
+			if err = uc.check(); err != nil {
+				return nil, err
+			}
 			uc.mutation = mutation
 			node, err = uc.sqlSave(ctx)
 			mutation.done = true
@@ -107,7 +110,8 @@ func (uc *UserCreate) SaveX(ctx context.Context) *User {
 	return v
 }
 
-func (uc *UserCreate) preSave() error {
+// check runs all checks and user-defined validators on the builder.
+func (uc *UserCreate) check() error {
 	return nil
 }
 
@@ -201,13 +205,13 @@ func (ucb *UserCreateBulk) Save(ctx context.Context) ([]*User, error) {
 		func(i int, root context.Context) {
 			builder := ucb.builders[i]
 			var mut Mutator = MutateFunc(func(ctx context.Context, m Mutation) (Value, error) {
-				if err := builder.preSave(); err != nil {
-					return nil, err
-				}
 				mutation, ok := m.(*UserMutation)
 				if !ok {
 					return nil, fmt.Errorf("unexpected mutation type %T", m)
 				}
+				if err := builder.check(); err != nil {
+					return nil, err
+				}
 				builder.mutation = mutation
 				nodes[i], specs[i] = builder.createSpec()
 				var err error