how to use bob's ORM correctly without code generation?

[asv]

I'm experimenting with bob as part of making the decision to replace goqu in my project, but can't figure out how to properly use bob's ORM without generating code. The documentation on the site is out of date and now it's completely unclear what to do. I'm trying this code (trying to adapt examples from outdated documentation):

package main

import (
	"context"
	"fmt"
	"time"

	"github.com/aarondl/opt/omit"
	"github.com/stephenafamo/bob"
	"github.com/stephenafamo/bob/dialect/psql"
	"github.com/stephenafamo/bob/dialect/psql/dialect"
	"github.com/stephenafamo/bob/orm"
)

type Docket struct {
	DocketID   string    `db:"docket_id,pk"`
	CreateTime time.Time `db:"create_time"`
}

func (d Docket) PrimaryKeyVals() bob.Expression {
	return psql.Arg(d.DocketID)
}

type DocketSetter struct {
	DocketID   omit.Val[string]    `db:"docket_id,pk"`
	CreateTime omit.Val[time.Time] `db:"create_time"`

	orm.Setter[*Docket, *dialect.InsertQuery, *dialect.UpdateQuery]
}

func main() {
	table := psql.NewTable[Docket, DocketSetter]("", "dockets")
	fmt.Println(table.Insert(DocketSetter{
		DocketID:   omit.From("123"),
		CreateTime: omit.From(time.Now()),
	}).MustBuild(context.Background()))
}

but I get panic:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x18 pc=0x102774894]

goroutine 1 [running]:
main.(*DocketSetter).Apply(0x0?, 0x1?)
	<autogenerated>:1 +0x24
github.com/stephenafamo/bob.BaseQuery[...].Apply(...)
	/Users/asmirnov/gocode/pkg/mod/github.com/stephenafamo/[email protected]/query.go:99
github.com/stephenafamo/bob/dialect/psql.(*Table[...]).Insert(0x1027e47a0, {0x14000123ee0, 0x1, 0x7})
	/Users/asmirnov/gocode/pkg/mod/github.com/stephenafamo/[email protected]/dialect/psql/table.go:92 +0x230
main.main()
	/Users/asmirnov/Projects/xxx/yyy/zzz/bob/main.go:33 +0xc8

By the way, maybe still return an error when using the library API incorrectly, instead of panicking? Thanks!

[stephenafamo]

There are other methods in orm.Setter[*Docket, *dialect.InsertQuery, *dialect.UpdateQuery] that need to be implemented.

table.Insert is calling one of those methods (Apply) and you get a panic because it is nil.

It is similar to this code:

type DocketSetter struct {
	DocketID   omit.Val[string]    `db:"docket_id,pk"`
	CreateTime omit.Val[time.Time] `db:"create_time"`

	Setter any // orm.Setter is an interface, so when by default, the value is nil
}

You should properly implement the setter interface. For example, if the code was generated, it will look something like this:

func (s DocketSetter) SetColumns() []string {
	vals := make([]string, 0, 2)
	if !s.DocketID.IsUnset() {
		vals = append(vals, "docket_id")
	}

	if !s.CreateTime.IsUnset() {
		vals = append(vals, "create_time")
	}

	return vals
}

func (s *DocketSetter) Apply(q *dialect.InsertQuery) {
	q.AppendValues(bob.ExpressionFunc(func(ctx context.Context, w io.Writer, d bob.Dialect, start int) ([]any, error) {
		vals := make([]bob.Expression, 2)
		if s.DocketID.IsUnset() {
			vals[0] = psql.Raw("DEFAULT")
		} else {
			vals[0] = psql.Arg(s.DocketID)
		}

		if s.CreateTime.IsUnset() {
			vals[1] = psql.Raw("DEFAULT")
		} else {
			vals[1] = psql.Arg(s.CreateTime)
		}

		return bob.ExpressSlice(ctx, w, d, start, vals, "", ", ", "")
	}))
}

func (s VideoSetter) UpdateMod() bob.Mod[*dialect.UpdateQuery] {
	return um.Set(s.Expressions()...)
}

func (s VideoSetter) Expressions(prefix ...string) []bob.Expression {
	exprs := make([]bob.Expression, 0, 2)

	if !s.DocketID.IsUnset() {
		exprs = append(exprs, expr.Join{Sep: " = ", Exprs: []bob.Expression{
			psql.Quote(append(prefix, "docket_id")...),
			psql.Arg(s.DocketID),
		}})
	}

	if !s.CreateTime.IsUnset() {
		exprs = append(exprs, expr.Join{Sep: " = ", Exprs: []bob.Expression{
			psql.Quote(append(prefix, "create_time")...),
			psql.Arg(s.CreateTime),
		}})
	}

	return exprs
}

[stephenafamo]

As Bob added more capabilities to handle more complex use cases, it has now become quite tedious to use the ORM capabilities without code generation.

If you can, try the code generation, it is likely quicker to test things out without having to write these by hand. If you do not want to have to setup a DB just to test, you can also use bobgen-sql which will generate code from migration files.