fix rewrite error handing

pkg/storage/feed/feed.go

@@ -22,6 +22,7 @@ import (
 	"reflect"
 	"strconv"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/benbjohnson/clock"
@@ -578,10 +579,14 @@ func (s *storage) blockDependencies() block.Dependencies {
 }
 
 func (s *storage) rewrite(ctx context.Context, feeds []*model.Feed) ([]*model.Feed, error) {
-	rewritten := make([]*model.Feed, 0, len(feeds))
-	var wg sync.WaitGroup
-	var errs []error
-	var mu sync.Mutex
+	var (
+		rewritten = make([]*model.Feed, 0, len(feeds))
+		wg        sync.WaitGroup
+		mu        sync.Mutex
+		errs      []error
+		dropped   atomic.Int32
+	)
+
 	for _, item := range feeds { // TODO: Limit the concurrency & goroutine number.
 		wg.Add(1)
 		go func(item *model.Feed) {
@@ -596,6 +601,7 @@ func (s *storage) rewrite(ctx context.Context, feeds []*model.Feed) ([]*model.Fe
 			}
 			if len(labels) == 0 {
 				log.Debug(ctx, "drop feed", "id", item.ID)
+				dropped.Add(1)
 
 				return // Drop empty labels.
 			}
@@ -607,7 +613,7 @@ func (s *storage) rewrite(ctx context.Context, feeds []*model.Feed) ([]*model.Fe
 		}(item)
 	}
 	wg.Wait()
-	if allFailed := len(errs) == len(feeds); allFailed {
+	if allFailed := len(errs) == len(feeds)-int(dropped.Load()); allFailed {
 		return nil, errs[0]
 	}
 	if len(errs) > 0 {