Also happened to find this problem. I deleted a directory that was being watched, then I tried to invoke inotify.RemoveWatch and it erred out "inotify_rm_watch: invalid argument". I think disallowing to remove watch on a deleted directory is the normal behavior of kernel. inotify.go should delete the keys from watches and paths map and suppress the error returned by syscall.InotifyRmWatch in this situation.

@agorman I think you fix is wrong, ok in the statement if !ok && success == -1 {should always be true. My fix is as follows

diff --git a/vendor/golang.org/x/exp/inotify/inotify_linux.go b/vendor/golang.org/x/exp/inotify/inotify_linux.go
index 901f308..c8bd944 100644
--- a/vendor/golang.org/x/exp/inotify/inotify_linux.go
+++ b/vendor/golang.org/x/exp/inotify/inotify_linux.go
@@ -141,7 +141,10 @@ func (w *Watcher) RemoveWatch(path string) error {
        }
        success, errno := syscall.InotifyRmWatch(w.fd, watch.wd)
        if success == -1 {
-               return os.NewSyscallError("inotify_rm_watch", errno)
+               // If path not exists, we should continue delete keys from watchs and paths
+               if _, err := os.Stat(path); err == nil {
+                       return os.NewSyscallError("inotify_rm_watch", errno)
+               }
        }
        delete(w.watches, path)
        // Locking here to protect the read from paths in readEvents.

Doh, you're right about my logic error. Good catch. I don't think this change quite fixes it either though. If a directory was deleted and then RemoveWatch is called it will still error without deleting the watch internally.

I propose that we just move the internal deletes up and keep the error handling the same. That way users can handle the error as they see fit but the watch is cleaned up properly internally.

agorman/exp@9382284

My patch fix the situation that the path was deleted and retrying to remove the watch is useless. But if InotifyRmWatch returns error due to other problems which we don't know if retry helps, I think maybe we need to add a forceRemove bool field to func (w *Watcher) RemoveWatch(path string) error. If forceRemove is set, we delete keys from watches and paths map even if error returns.

I'm fine with not doing the syscall to inotify if the directory doesn't exist as long as the internal maps are cleaned up even if an error is returned. I don't think a user should have to force anything to allow for the watches to be removed internally even if there is no actual inotify watch.

Deleted this code instead. See github.com/fsnotify for more maintained code.