FSNotify Bug TestCase

fs_notify_rm_watched_dir_with_file_err.go

package main

/**
 * Exhibits a bug in fsnotify where removing with "rm -r" a watched dir which includes a watched file
 * causes an error. Rather than delete events for each item and the containing folder.
 *
 * Steps to repro:
 *  1.) Watch a directory
 *  2.) Watch a file in the directory
 *  3.) Rm -rf the directory
 **/

import (
	"github.com/howeyc/fsnotify"
	"log"
	"path/filepath"
	"io/ioutil"
	"time"
	"os/exec"
)

func panic_if(err error) {
	if err != nil {
		panic(err)
	}
}

func main() {
	done := make(chan bool)

	w, err := fsnotify.NewWatcher()
	panic_if(err)

	tempDir, err := ioutil.TempDir("", "a_dir")
	panic_if(err)
	log.Println(tempDir)

	go func() {
		for {
			select {
			case ev := <-w.Event:
				log.Println("event:", ev)
			case err := <-w.Error:
				panic(err)
				done <- true
			}
		}
	}()

	go func() {
		// Step 1.)
		log.Println("Watching new dir at", tempDir)
		w.Watch(tempDir);
		time.Sleep(1 * time.Second)

		// Step 2.)
		f, err := ioutil.TempFile(tempDir, "a_file")
		panic_if(err)
		f_info, err := f.Stat()
		panic_if(err)
		f_path := filepath.Join(tempDir, f_info.Name())
		log.Println("Watch new file at", f_path)
		w.Watch(f_path);
		err = f.Close()
		panic_if(err)
		time.Sleep(1 * time.Second)

		// Step 3.)
		letTestRunRm := false
		if (letTestRunRm) {
			// I left this behind a flag because I don't
			// feel comfortable running rm -rf on other people's
			// machine's without asking.
			rmCmd := exec.Command("rm", "-rf", tempDir)
			log.Printf("\n\nTry to delete watched dir with %v", rmCmd.Args)
			err = rmCmd.Run()
			panic_if(err)
		} else {
			log.Println("Please go run ( rm -rf ",
						tempDir,
						") and notice the failure.")
		}
	}()

	<- done
}