op-supervisor: improve finality errors and logging (#13662)

op-supervisor/supervisor/backend/db/query.go

@@ -169,11 +169,11 @@ func (db *ChainsDB) FinalizedL1() eth.BlockRef {
 func (db *ChainsDB) Finalized(chainID types.ChainID) (types.BlockSeal, error) {
 	finalizedL1 := db.finalizedL1.Get()
 	if finalizedL1 == (eth.L1BlockRef{}) {
-		return types.BlockSeal{}, errors.New("no finalized L1 signal, cannot determine L2 finality yet")
+		return types.BlockSeal{}, fmt.Errorf("no finalized L1 signal, cannot determine L2 finality of chain %s yet", chainID)
 	}
 	derived, err := db.LastDerivedFrom(chainID, finalizedL1.ID())
 	if err != nil {
-		return types.BlockSeal{}, errors.New("could not find what was last derived from the finalized L1 block")
+		return types.BlockSeal{}, fmt.Errorf("could not find what was last derived in L2 chain %s from the finalized L1 block %s: %w", chainID, finalizedL1, err)
 	}
 	return derived, nil
 }

op-supervisor/supervisor/backend/db/update.go

@@ -114,7 +114,7 @@ func (db *ChainsDB) UpdateFinalizedL1(finalized eth.BlockRef) error {
 	db.logger.Info("Updated finalized L1", "finalizedL1", finalized)
 	db.finalizedL1.Unlock()
 
-	// whenver the L1 Finalized changes, the L2 Finalized may change, notify subscribers
+	// whenever the L1 Finalized changes, the L2 Finalized may change, notify subscribers
 	db.NotifyL2Finalized()
 
 	return nil

op-supervisor/supervisor/backend/syncnode/node.go

@@ -245,7 +245,7 @@ func (m *ManagedNode) onCrossSafeUpdate(pair types.DerivedBlockSealPair) {
 }
 
 func (m *ManagedNode) onFinalizedL2(seal types.BlockSeal) {
-	m.log.Debug("updating finalized L2", "finalized", seal)
+	m.log.Info("updating finalized L2", "finalized", seal)
 	ctx, cancel := context.WithTimeout(m.ctx, nodeTimeout)
 	defer cancel()
 	id := seal.ID()