From: Pieter Droogendijk <pieter@binky.org.uk>
Date: Sun, 8 Feb 2015 02:50:54 +0000 (+0100)
Subject: When removing, delete from watches before removing from inotify (fixes go-fsnotify... 
X-Git-Tag: v1.7.2~222
X-Git-Url: https://go.fuhry.dev/?a=commitdiff_plain;h=ae966a22c363db3ce4b6cf5e2994250e4b51b93a;p=fsnotify.git

When removing, delete from watches before removing from inotify (fixes go-fsnotify/fsnotify#40)
---

diff --git a/inotify.go b/inotify.go
index 3978fb5..d7759ec 100644
--- a/inotify.go
+++ b/inotify.go
@@ -132,11 +132,20 @@ func (w *Watcher) Remove(name string) error {
 	if !ok {
 		return fmt.Errorf("can't remove non-existent inotify watch for: %s", name)
 	}
+	// inotify_rm_watch will return EINVAL if the file has been deleted;
+	// the inotify will already have been removed.
+	// That means we can safely delete it from our watches, whatever inotify_rm_watch does.
+	delete(w.watches, name)
 	success, errno := syscall.InotifyRmWatch(w.fd, watch.wd)
 	if success == -1 {
+		// TODO: Perhaps it's not helpful to return an error here in every case.
+		// the only two possible errors are:
+		// EBADF, which happens when w.fd is not a valid file descriptor of any kind.
+		// EINVAL, which is when fd is not an inotify descriptor or wd is not a valid watch descriptor.
+		// Watch descriptors are invalidated when they are removed explicitly or implicitly;
+		// explicitly by inotify_rm_watch, implicitly when the file they are watching is deleted.
 		return errno
 	}
-	delete(w.watches, name)
 	return nil
 }
 
diff --git a/inotify_test.go b/inotify_test.go
index 32432c6..035ee8f 100644
--- a/inotify_test.go
+++ b/inotify_test.go
@@ -252,3 +252,41 @@ func TestInotifyStress(t *testing.T) {
 		}
 	}
 }
+
+func TestInotifyRemoveTwice(t *testing.T) {
+	testDir := tempMkdir(t)
+	defer os.RemoveAll(testDir)
+	testFile := filepath.Join(testDir, "testfile")
+
+	handle, err := os.Create(testFile)
+	if err != nil {
+		t.Fatalf("Create failed: %v", err)
+	}
+	handle.Close()
+
+	w, err := NewWatcher()
+	if err != nil {
+		t.Fatalf("Failed to create watcher: %v", err)
+	}
+	defer w.Close()
+
+	err = w.Add(testFile)
+	if err != nil {
+		t.Fatalf("Failed to add testFile: %v", err)
+	}
+
+	err = os.Remove(testFile)
+	if err != nil {
+		t.Fatalf("Failed to remove testFile: %v", err)
+	}
+
+	err = w.Remove(testFile)
+	if err != syscall.EINVAL {
+		t.Fatalf("Expected EINVAL from Remove, got: %v", err)
+	}
+
+	err = w.Remove(testFile)
+	if err == syscall.EINVAL {
+		t.Fatalf("Got EINVAL again, watch was not removed")
+	}
+}