Double firing of event

[riccardomanfrin]

Before reporting an issue, please ensure you are using the latest release of fsnotify.

Which operating system (GOOS) and version are you using?

Linux:
Distributor ID: Ubuntu
Description: Ubuntu 18.04.4 LTS
Release: 18.04
Codename: bionic

fsnotify version: ## v1.4.7 / 2018-01-09

Please describe the issue that occurred.

Modifying a file either with

 echo "helloworld" > /my/tmp/file

or by means of a generic editor (vim/nano/sublime) generates single or double OP 0x2 events on a random base (say 50% of the times I get single OP 0x2 events, and the other half I get the event twice).

Are you able to reproduce the issue? Please provide steps to reproduce and a code sample if possible.

Full code reference @ https://medium.com/@skdomino/watch-this-file-watching-in-go-5b5a247cf71f

This is the sensible part:

var watcher *fsnotify.Watcher

//Listen on file changes
func Listen() {
	defer watcher.Close()
	done := make(chan bool)

	go func() {
		for {
			select {
			// watch for events
			case event := <-watcher.Events:
				res, err := Read(&event.Name)
				if err != nil {
					continue
				}
				fmt.Printf("EVENT! %#v\n", event)
				logger.Log.Debug(*res)
				// watch for errors
			case err := <-watcher.Errors:
				logger.Fatal(err)
			}
		}
	}()

	<-done
}

[snowyyj001]

I user the example code for test and it also trigger two times, it happened 100%.
if ev.Op&fsnotify.Write == fsnotify.Write {
//here will be called two times
}

[zhaocy]

I had the same problem running the sample。 on windows 7 operation system

[dmgcodevil]

in my case, it fires 10+ events. mac os. go 1.13

[dkotik]

Ubuntu 19.10 double firing for me as well.

[riccardomanfrin]

best way to keep it under control is to md5sum compare changes

[chenqinghe]

windows 10, go1.14 double firing too.

[ellis2323]

windows 10 (version 2004), go1.14 double firing as well

[PaluMacil]

same double READ result, Ubuntu 20.04

[sgon00]

Debian 10 (MX Linux), Go 1.16.
I don't see double firing by using echo command when modifying the file.
But I see double firing when using rich editors such as vscode.

Possible Related Issues:
#122
microsoft/vscode#9419

[flysand7]

Windows 10, go 1.17.2
My experience matches that of @sgon00. When I use echo and pipe redirects, the firing only happens once.
But when I use sublime text to modify the file, it fires two times at a time.

[arp242]

I'm closing this as a duplicate of #372; as mentioned in that issue, many editors don't "just" write a file, but will instead write it to a new file and then rename it.

Also, #470 should make things a little but more consistent, on Linux at least.