hyperledger/fabric · error

Block header is nil

Error message

Block header is nil

What it means

coordinator.StoreBlock requires block.Header to be non-nil because it logs and commits using block.Header.Number. When the header is missing the block cannot be sequenced or validated, so StoreBlock returns this error before any processing.

Solutions

1. Re-fetch the block from the orderer/peer to obtain the full block with header
2. Check that the block deserialization path (protoutil.UnmarshalBlock / FromBlock) preserved the header
3. Fix test or repair code to include a valid Header with BlockNumber
4. Inspect the upstream block producer if headers are systematically missing

Example fix

// before
blk, _ := protoutil.UnmarshalBlock(bytes) // partial
c.StoreBlock(blk, pvt)
// after
if blk.Header == nil || blk.Data == nil {
    return fmt.Errorf("incomplete block %d", blk.GetHeader().GetNumber())
}
c.StoreBlock(blk, pvt)

if block == nil || block.Header == nil || block.Data == nil {
    return errors.New("incomplete block")
}

func hasHeader(b *common.Block) bool {
    return b != nil && b.Header != nil
}

When it happens

Trigger: Calling StoreBlock with a common.Block that has Data set but Header nil — typically from a malformed/incomplete deserialization or hand-built block.

Common situations: See trigger scenarios.

Related errors

• Block data is empty
• block data size( ) is different from Tx filter size( )
• Block.Metadata is nil or Block.Metadata lacks a Tx filter…
• commit failed
• failed to commit private data

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/ddc70a54e68892e2. Report an issue: GitHub.

Appendix: source

Thrown at gossip/privdata/coordinator.go:158

		mspID:                          mspID,
		store:                          store,
		selfSignedData:                 selfSignedData,
		transientBlockRetention:        config.TransientBlockRetention,
		logger:                         logger.With("channel", support.ChainID),
		metrics:                        metrics,
		pullRetryThreshold:             config.PullRetryThreshold,
		skipPullingInvalidTransactions: config.SkipPullingInvalidTransactions,
		idDeserializerFactory:          idDeserializerFactory,
	}
}

// StoreBlock stores block with private data into the ledger
func (c *coordinator) StoreBlock(block *common.Block, privateDataSets util.PvtDataCollections) error {
	if block.Data == nil {
		return errors.New("Block data is empty")
	}
	if block.Header == nil {
		return errors.New("Block header is nil")
	}

	c.logger.Infof("Received block [%d] from buffer", block.Header.Number)

	c.logger.Debugf("Validating block [%d]", block.Header.Number)

	validationStart := time.Now()
	err := c.Validator.Validate(block)
	c.reportValidationDuration(time.Since(validationStart))
	if err != nil {
		c.logger.Errorf("Validation failed: %+v", err)
		return err
	}

	blockAndPvtData := &ledger.BlockAndPvtData{
		Block:          block,
		PvtData:        make(ledger.TxPvtDataMap),
		MissingPvtData: make(ledger.TxMissingPvtData),

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