append missing tail manually

Author: Wondertan

sync/sync_head.go

@@ -124,8 +124,8 @@ func (s *Syncer[H]) Tail(ctx context.Context) (H, error) {
 		// Configured Tail has changed - get a new one and resolve the diff
 
 		currentTail, newTail := tail, tail
-
-		if s.Params.SyncFromHash != nil {
+		switch {
+		case s.Params.SyncFromHash != nil:
 			// check first locally if the new Tail exists
 			newTail, err = s.store.Get(ctx, s.Params.SyncFromHash)
 			if err != nil {
@@ -138,8 +138,16 @@ func (s *Syncer[H]) Tail(ctx context.Context) (H, error) {
 						err,
 					)
 				}
+				err = s.store.Append(ctx, newTail)
+				if err != nil {
+					return tail, fmt.Errorf(
+						"appending the new tail header(%d): %w",
+						newTail.Height(),
+						err,
+					)
+				}
 			}
-		} else if s.Params.SyncFromHeight != 0 {
+		case s.Params.SyncFromHeight != 0:
 			// check first locally if the new Tail exists
 			newTail, err = s.store.GetByHeight(ctx, s.Params.SyncFromHeight)
 			if err != nil {
@@ -152,6 +160,14 @@ func (s *Syncer[H]) Tail(ctx context.Context) (H, error) {
 						err,
 					)
 				}
+				err = s.store.Append(ctx, newTail)
+				if err != nil {
+					return tail, fmt.Errorf(
+						"appending the new tail header(%d): %w",
+						newTail.Height(),
+						err,
+					)
+				}
 			}
 		}
 

sync/sync_head_test.go

@@ -77,7 +77,10 @@ func TestSyncer_TailInit(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			ds := dssync.MutexWrap(datastore.NewMapDatastore())
-			localStore, err := store.NewStore[*headertest.DummyHeader](ds, store.WithWriteBatchSize(1))
+			localStore, err := store.NewStore[*headertest.DummyHeader](
+				ds,
+				store.WithWriteBatchSize(1),
+			)
 			require.NoError(t, err)
 			err = localStore.Start(ctx)
 			require.NoError(t, err)
@@ -113,6 +116,8 @@ func TestSyncer_TailInit(t *testing.T) {
 			err = syncer.Start(ctx)
 			require.NoError(t, err)
 
+			time.Sleep(time.Millisecond * 10)
+
 			// ensure that the Syncer moved to the new tail after restart
 			storeTail, err = localStore.Tail(ctx)
 			require.NoError(t, err)