fix: delete the timer entry on natural expiry

1 files changed, 14 insertions, 2 deletions

diff --git a/internal/notify/service.go b/internal/notify/service.go
index d775aa6..22d7830 100644
--- a/internal/notify/service.go
+++ b/internal/notify/service.go
@@ -115,9 +115,21 @@ func (s *Service) arm(id uint32, ms int64) {
 	if ms <= 0 {
 		return
 	}
-	s.timers[id] = time.AfterFunc(time.Duration(ms)*time.Millisecond, func() {
-		s.store.Expire(id)
+	var t *time.Timer
+	t = time.AfterFunc(time.Duration(ms)*time.Millisecond, func() {
+		s.mu.Lock()
+		current := s.timers[id] == t
+		if current {
+			delete(s.timers, id)
+		}
+		s.mu.Unlock()
+		// Only the current timer may expire the id: a timer left over from a
+		// replaced notification must not close its successor.
+		if current {
+			s.store.Expire(id)
+		}
 	})
+	s.timers[id] = t
 }
 
 func (s *Service) stopTimer(id uint32) {