correct zero hash in log (iotexproject#2389)

Author: dustinxie

blockchain/blockchain.go

@@ -492,9 +492,14 @@ func (bc *blockchain) commitBlock(blk *block.Block) error {
 	putTimer := bc.timerFactory.NewTimer("putBlock")
 	err = bc.dao.PutBlock(ctx, blk)
 	putTimer.End()
-	if err != nil {
+	switch {
+	case errors.Cause(err) == blockdao.ErrAlreadyExist:
+		return nil
+	case err != nil:
 		return err
 	}
+	blkHash := blk.HashBlock()
+	blk.HeaderLogger(log.L()).Info("Committed a block.", log.Hex("tipHash", blkHash[:]))
 	blockMtc.WithLabelValues("numActions").Set(float64(len(blk.Actions)))
 	// emit block to all block subscribers
 	bc.emitToSubscribers(blk)

blockchain/blockdao/blockdao.go

@@ -60,6 +60,7 @@ var (
 	heightToFileBucket = []byte("h2f")
 )
 
+// vars
 var (
 	cacheMtc = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
@@ -68,12 +69,9 @@ var (
 		},
 		[]string{"result"},
 	)
-	patternLen = len("00000000.db")
-	suffixLen  = len(".db")
-	// ErrNotOpened indicates db is not opened
-	ErrNotOpened = errors.New("DB is not opened")
-
-	// ErrNotSupported indicates not supported
+	patternLen      = len("00000000.db")
+	suffixLen       = len(".db")
+	ErrAlreadyExist = errors.New("block already exist")
 	ErrNotSupported = errors.New("feature not supported")
 )
 
@@ -403,7 +401,7 @@ func (dao *blockDAO) PutBlock(ctx context.Context, blk *block.Block) error {
 	blkHash, err := dao.getBlockHash(blkHeight)
 	if err == nil && blkHash != hash.ZeroHash256 {
 		log.L().Debug("Block already exists.", zap.Uint64("height", blkHeight))
-		return nil
+		return ErrAlreadyExist
 	}
 	// early exit if it's a db io error
 	if err != nil && errors.Cause(err) != db.ErrNotExist && errors.Cause(err) != db.ErrBucketNotExist {
@@ -431,8 +429,6 @@ func (dao *blockDAO) PutBlock(ctx context.Context, blk *block.Block) error {
 			return err
 		}
 	}
-
-	blk.HeaderLogger(log.L()).Info("Committed a block.", log.Hex("tipHash", blkHash[:]))
 	return nil
 }
 

blockchain/blockdao/blockdao_test.go

@@ -199,6 +199,9 @@ func TestBlockDAO(t *testing.T) {
 			require.Equal(blks[i], blk)
 		}
 
+		// commit an existing block
+		require.Equal(ErrAlreadyExist, dao.PutBlock(ctx, blks[2]))
+
 		// Test getReceiptByActionHash
 		for j := range daoTests[0].hashTotal {
 			h := hash.BytesToHash256(daoTests[0].hashTotal[j])