Starting a goroutine without knowing when to stop it
Mistake
It is unclear when this goroutine will stop. The channel implementation in foo() is unknown. If this never closes then it is a leak.
ch := foo()
go func(){
for v := range ch {
// ...
}
}()
Fix
We instead should be signaling resources letting them know it is time to close
func main() {
w := newWatcher()
defer w.close()
// ...
}
func newWatcher() watcher {
w := watcher{}
go w.watch()
return w
}
func (w watcher) close(){
// close resource
}