fix(GODT-2800): Pending Subscriptions Cleanup

Ensure pending subscriptions are cleaned up with `Service.Close()` or
we can leak go routines.

internal/services/userevents/eventid_store.go

@@ -62,8 +62,8 @@ type VaultEventIDStore struct {
 	vault *vault.User
 }
 
-func NewVaultEventIDStore(vault *VaultEventIDStore) *VaultEventIDStore {
-	return &VaultEventIDStore{vault: vault.vault}
+func NewVaultEventIDStore(vault *vault.User) *VaultEventIDStore {
+	return &VaultEventIDStore{vault: vault}
 }
 
 func (v VaultEventIDStore) Load(_ context.Context) (string, error) {

internal/services/userevents/service.go

@@ -32,7 +32,9 @@ import (
 	"github.com/ProtonMail/proton-bridge/v3/internal"
 	"github.com/ProtonMail/proton-bridge/v3/internal/events"
 	"github.com/ProtonMail/proton-bridge/v3/pkg/cpc"
+	"github.com/bradenaw/juniper/xslices"
 	"github.com/sirupsen/logrus"
+	"golang.org/x/exp/slices"
 )
 
 // Service polls from the given event source and ensures that all the respective subscribers get notified
@@ -125,6 +127,27 @@ func (s Subscription) cancel() {
 	}
 }
 
+func (s Subscription) close() {
+	if s.User != nil {
+		s.User.close()
+	}
+	if s.Refresh != nil {
+		s.Refresh.close()
+	}
+	if s.Address != nil {
+		s.Address.close()
+	}
+	if s.Labels != nil {
+		s.Labels.close()
+	}
+	if s.Messages != nil {
+		s.Messages.close()
+	}
+	if s.UserUsedSpace != nil {
+		s.UserUsedSpace.close()
+	}
+}
+
 // Subscribe adds new subscribers to the service.
 // This method can safely be called during event handling.
 func (s *Service) Subscribe(subscription Subscription) {
@@ -276,6 +299,28 @@ func (s *Service) run(ctx context.Context, lastEventID string) {
 	}
 }
 
+// Close should be called after the service has been cancelled to clean up any remaining pending operations.
+func (s *Service) Close() {
+	s.pendingSubscriptionsLock.Lock()
+	defer s.pendingSubscriptionsLock.Unlock()
+
+	// Cleanup pending removes.
+	for _, subscription := range s.pendingSubscriptionsRemove {
+		subscription.close()
+	}
+
+	// Cleanup pending adds.
+	for _, subscription := range xslices.Filter(s.pendingSubscriptionsAdd, func(sub Subscription) bool {
+		return !slices.Contains(s.pendingSubscriptionsRemove, sub)
+	}) {
+		subscription.cancel()
+		subscription.close()
+	}
+
+	s.pendingSubscriptionsRemove = nil
+	s.pendingSubscriptionsAdd = nil
+}
+
 func (s *Service) handleEvent(ctx context.Context, lastEventID string, event proton.Event) error {
 	s.log.WithFields(logrus.Fields{
 		"old": lastEventID,