Cache: Coherence

core/cache/lxdprofilewatcher.go

@@ -342,7 +342,6 @@ func (w *MachineLXDProfileWatcher) removeUnit(_ string, value interface{}) {
 	if len(w.applications) > 0 && !profile.Empty() {
 		notify = true
 	}
-	return
 }
 
 // provisionedChanged notifies when called.  Topic subscribed to is specific to

core/cache/model_test.go

@@ -120,7 +120,7 @@ func (s *ModelSuite) TestConfigWatcherOneValue(c *gc.C) {
 	wc.AssertOneChange()
 }
 
-func (s *ModelSuite) TestConfigWatcherOneValueOtherChange(c *gc.C) {
+func (s *ModelSuite) TestConfigWatcherSameValueHasNoChange(c *gc.C) {
 	m := s.NewModel(modelChange)
 	w := m.WatchConfig("key")
 
@@ -146,6 +146,43 @@ func (s *ModelSuite) TestConfigWatcherOneValueOtherChange(c *gc.C) {
 	wc.AssertNoChange()
 }
 
+func (s *ModelSuite) TestConfigWatcherValueHasChangeBackToOriginalValue(c *gc.C) {
+	m := s.NewModel(modelChange)
+	w := m.WatchConfig("key")
+
+	// The worker is the first and only resource (1).
+	resourceId := uint64(1)
+	s.AssertWorkerResource(c, m.Resident, resourceId, true)
+	defer func() {
+		workertest.CleanKill(c, w)
+		s.AssertWorkerResource(c, m.Resident, resourceId, false)
+	}()
+
+	wc := cache.NewNotifyWatcherC(c, w)
+	// Sends initial event.
+	wc.AssertOneChange()
+
+	change := modelChange
+	change.Config = map[string]interface{}{
+		"key":     "other",
+		"another": "changed",
+	}
+
+	m.SetDetails(change)
+	wc.AssertOneChange()
+
+	// Set it back to the original value and ensure that we do get
+	// a change event again.
+	change = modelChange
+	change.Config = map[string]interface{}{
+		"key":     "value",
+		"another": "changed",
+	}
+
+	m.SetDetails(change)
+	wc.AssertOneChange()
+}
+
 func (s *ModelSuite) TestConfigWatcherSameValuesCacheHit(c *gc.C) {
 	m := s.NewModel(modelChange)
 

core/cache/watcher.go

@@ -156,6 +156,7 @@ func (w *ConfigWatcher) configChanged(topic string, value interface{}) {
 		return
 	}
 	w.notify()
+	w.hash = hash
 }
 
 // StringsWatcher will return what has changed.
@@ -272,15 +273,6 @@ type PredicateStringsWatcher struct {
 	fn predicateFunc
 }
 
-// newChangeWatcher provides a PredicateStringsWatcher which notifies
-// with all strings passed to it.
-func newChangeWatcher(values ...string) *PredicateStringsWatcher {
-	return &PredicateStringsWatcher{
-		stringsWatcherBase: newStringsWatcherBase(values...),
-		fn:                 func(string) bool { return true },
-	}
-}
-
 func regexpPredicate(compiled *regexp.Regexp) func(string) bool {
 	return func(value string) bool { return compiled.MatchString(value) }
 }