Auto cleaning temp dirs

main.go

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package main

import (
	"fmt"
	"os"
	"runtime"
	"time"
)

func main() {
	foo()
	foo()

	runtime.GC()
	time.Sleep(time.Second)
}

func foo() {
	var tmp string
	defer TempDir(&tmp)()

	fmt.Println("foo temp is", tmp)
	bar()
}

func bar() {
	var tmp string
	defer TempDir(&tmp)()

	fmt.Println("bar temp is", tmp)
}

func TempDir(s *string) func() {
	d, _ := os.MkdirTemp("", "")
	*s = d
	x := "."
	f := func() { x = "" }

	runtime.SetFinalizer(&x, func(*string) {
		os.RemoveAll(d)
		fmt.Println("deleted", d)
	})
	return f
}