aghos: imp docs

CHANGELOG.md

@@ -55,11 +55,16 @@ NOTE: Add new changes BELOW THIS COMMENT.
 
 - Go 1.21 support.  Future versions will require at least Go 1.22 to build.
 
+### Fixed
+
+- Incorrect tracking of the system hosts file's changes ([#6711]).
+
 ### Removed
 
 - Go 1.20 support, as it has reached end of life.
 
 [#6679]: https://github.com/AdguardTeam/AdGuardHome/issues/6679
+[#6711]: https://github.com/AdguardTeam/AdGuardHome/issues/6711
 
 [go-toolchain]: https://go.dev/blog/toolchain
 

internal/aghos/fswatcher.go

@@ -20,10 +20,13 @@ type event = struct{}
 // FSWatcher tracks all the fyle system events and notifies about those.
 //
 // TODO(e.burkov, a.garipov): Move into another package like aghfs.
+//
+// TODO(e.burkov):  Add tests.
 type FSWatcher interface {
 	// Start starts watching the added files.
 	Start() (err error)
 
+	// Close stops watching the files and closes an update channel.
 	io.Closer
 
 	// Events returns the channel to notify about the file system events.
@@ -103,6 +106,11 @@ func (w *osWatcher) Add(name string) (err error) {
 	name = filepath.Join("/", name)
 	w.files.Add(name)
 
+	// Watch the directory and filter the events by the file name, since the
+	// common recomendation to the fsnotify package is to watch the directory
+	// instead of the file itself.
+	//
+	// See https://pkg.go.dev/github.com/fsnotify/fsnotify@v1.7.0#readme-watching-a-file-doesn-t-work-well.
 	if !fi.IsDir() {
 		name = filepath.Dir(name)
 	}