Codegen - return interfaces instead of private structs

[randallmlough]

Is there a reason codegen returns private structs over exported or interfaces? If these methods could return an interface and or in some instances a generic interface, like the one below, it could open up some cool opportunities.

// prisma-client-go 
// GENERATED FILE

// generic transaction interface
type Tx[T any] interface {
	ExtractQuery() builder.Query
	IsTx()
	Result() T
}

// example of a model returning the Tx interface
func (r activityCreateOne) Tx() Tx[*ActivityModel] {
	v := NewactivityUniqueTxResult()
	v.query = r.query
	v.query.TxResult = make(chan []byte, 1)
	return v
}

By returning an interface specifically on Tx() we can create our own wrapping interface that enables "query builder" methods.

// developers own wrapper interface
type Executor[T any] interface {
	ExtractQuery() builder.Query
	Exec(ctx context.Context) (T, error)
	Tx() prisma.Tx[T]
}

// query builders functions
func buildActivityQuery(db *db.DB, input Input) Executor[*prisma.ActivityModel] {
	return db.Activity.CreateOne(
		prisma.Activity.Title.Set(input.title),
		prisma.Activity.Description.Set(input.description),
		prisma.Activity.StartDate.Set(input.startDate),
		prisma.Activity.Location.Set(input.location),
	)
}

func buildGroupQuery(db *db.DB, input string) Executor[*prisma.GroupModel] {
	return db.Group.CreateOne(
		prisma.Group.Name.Set(input),
	)
}

// example helper functions that either executes the query
func CreateActivity(ctx context.Context, db *db.DB, input Input) (*prisma.ActivityModel, error) {
	act := buildActivityQuery(db, input)
	return act.Exec(ctx)
}

// or create a transaction
func CreateActivityTx(ctx context.Context, db *db.DB, input Input) (prisma.Tx[*prisma.ActivityModel], error) {
	act := buildActivityQuery(db, input)
	return act.Tx(), nil
}

func DoSomethingTheNeedsTransactions(ctx context.Context, db *db.DB, input Input) (*prisma.ActivityModel, error) {
	act, _ := CreateActivityTx(ctx, db, input)
	group := buildGroupQuery(db, "some name").Tx()
	if err := db.Prisma.Transaction(act, group).Exec(ctx); err != nil {
		return nil, err
	}
	return act.Result(), nil
}

// these same query builders can then be used in a mocks expectation
mock.Activity.Expect(
	BuildActivityQuery(client, Input{}),
).Returns(expected)

[steebchen]

That's an interesting suggestion. Do you actually have the need in your app to use this?

The reason most of the methods are private is that most users don't need it, and I wanted to really think about the naming and so forth before making these public.

I prepared one small PR to make the transaction results public and it also renames the transaction interface to a better name: #1180.

When I have some more spare time, I might take another look and work on a bigger PR to make this more unified, maybe with generics where it works or makes sense. Thanks for the suggestion and the example code, that's really helpful!