add last data for empty data

Author: julienrbrt

block/internal/syncing/da_retriever.go

@@ -299,9 +299,10 @@ func (r *DARetriever) createEmptyDataForHeader(ctx context.Context, header *type
 	return &types.Data{
 		Txs: make(types.Txs, 0),
 		Metadata: &types.Metadata{
-			ChainID: header.ChainID(),
-			Height:  header.Height(),
-			Time:    header.BaseHeader.Time,
+			ChainID:      header.ChainID(),
+			Height:       header.Height(),
+			Time:         header.BaseHeader.Time,
+			LastDataHash: nil, // LastDataHash must be filled in the syncer, as it is not available here, block n-1 has not been processed yet.
 		},
 	}
 }

block/internal/syncing/syncer.go

@@ -382,6 +382,17 @@ func (s *Syncer) processHeightEvent(event *common.DAHeightEvent) {
 		return
 	}
 
+	// Last data must be got from store if the event comes from DA.
+	// When if the event comes from P2P, the sequencer and then all the full nodes contains the data.
+	if event.Source == common.SourceDA && bytes.Equal(event.Header.DataHash, common.DataHashForEmptyTxs) {
+		_, lastData, err := s.store.GetBlockData(s.ctx, currentHeight)
+		if err != nil {
+			s.logger.Error().Err(err).Msg("failed to get last data")
+			return
+		}
+		event.Data.LastDataHash = lastData.Hash()
+	}
+
 	// Try to sync the next block
 	if err := s.trySyncNextBlock(event); err != nil {
 		s.logger.Error().Err(err).Msg("failed to sync next block")