How to wrap errors in Go (wrong)

main_correct.go

// Correct way
package main

import (
	"errors"
	"fmt"
)

var errDoopsy = errors.New("doopsy")

func main() {
	err := fmt.Errorf("oopsy: %w", newError("doopsy"))
	if errors.Is(err, errDoopsy) {
		fmt.Println("doopsy error")
	} else {
		fmt.Println("unknown error")
	}
}

func newError(s string) error {
	switch s {
	case errDoopsy.Error():
		return errDoopsy
	default:
		return errors.New(s)
	}
}

main_wrong.go

// Wrong way
package main

import (
	"errors"
	"fmt"
)

var errDoopsy = errors.New("doopsy")

func main() {
	err := fmt.Errorf("oopsy: %v", newError("doopsy"))
	if errors.Is(err, errDoopsy) {
		fmt.Println("doopsy error")
	} else {
		fmt.Println("unknown error")
	}
}

func newError(s string) error {
	switch s {
	case errDoopsy.Error():
		return errDoopsy
	default:
		return errors.New(s)
	}
}