block metadata is either missing or contains too few entries

Error message

block metadata is either missing or contains too few entries

What it means

The block must include block-level metadata with at least as many entries as cb.BlockMetadataIndex_name. If Metadata is nil or too short, the verifier cannot read the SIGNATURES/ORDERER metadata needed for consensus verification, so the proposal is rejected.

Source

Thrown at orderer/consensus/smartbft/verifier.go:270

	if err != nil {
		return err
	}
	dataHashString := hex.EncodeToString(block.Header.DataHash)

	actualHashOfData := hex.EncodeToString(dataHash)
	if dataHashString != actualHashOfData {
		return errors.Errorf("data hash is %s but expected %s", dataHashString, actualHashOfData)
	}
	return nil
}

func (v *Verifier) verifyBlockDataAndMetadata(block *cb.Block, metadata []byte) ([]types.RequestInfo, error) {
	if block.Data == nil || len(block.Data.Data) == 0 {
		return nil, errors.New("empty block data")
	}

	if block.Metadata == nil || len(block.Metadata.Metadata) < len(cb.BlockMetadataIndex_name) {
		return nil, errors.New("block metadata is either missing or contains too few entries")
	}

	signatureMetadata, err := protoutil.GetMetadataFromBlock(block, cb.BlockMetadataIndex_SIGNATURES)
	if err != nil {
		return nil, err
	}
	ordererMetadataFromSignature := &cb.OrdererBlockMetadata{}
	if err := proto.Unmarshal(signatureMetadata.Value, ordererMetadataFromSignature); err != nil {
		return nil, errors.Wrap(err, "failed unmarshaling OrdererBlockMetadata")
	}

	// Ensure the view metadata in the block signature and in the proposal are the same

	metadataInBlock := &smartbftprotos.ViewMetadata{}
	if err := proto.Unmarshal(ordererMetadataFromSignature.ConsenterMetadata, metadataInBlock); err != nil {
		return nil, errors.Wrap(err, "failed unmarshaling smartbft metadata from block")
	}

View on GitHub (pinned to 2736b63f8f)

Solutions

Ensure block assembly initializes block.Metadata with entries up to and including BlockMetadataIndex_SIGNATURES
Regenerate the proposal using the current fabric protoutil helpers
Check for version drift between nodes producing and verifying blocks
Validate block structure locally before submitting to VerifyProposal

Example fix

// before
block.Metadata = nil
// after
block.Metadata = &cb.BlockMetadata{Metadata: make([][]byte, int(cb.BlockMetadataIndex_SIGNATURES)+1)}

Defensive patterns

Strategy: validation

Validate before calling

if block.Metadata == nil || len(block.Metadata.Metadata) < int(cb.BlockMetadataIndex_SIGNATURES)+1 {
    return errors.New("block metadata missing or too short")
}

Type guard

func hasSufficientMetadata(b *cb.Block) bool {
    return b.Metadata != nil && len(b.Metadata.Metadata) >= len(cb.BlockMetadataIndex_name)
}

Try / catch

if _, err := verifier.VerifyProposal(...); err != nil && strings.Contains(err.Error(), "metadata is either missing") {
    logger.Warn("proposal built without block metadata; discarding")
}

Prevention

Initialize metadata array up to BlockMetadataIndex_SIGNATURES during assembly
Use fabric protoutil helpers instead of hand-built blocks
Keep block-construction code version-aligned across nodes
Pre-validate block shape before calling VerifyProposal

When it happens

Trigger: VerifyProposal gets a block where block.Metadata is nil or len(block.Metadata.Metadata) < len(cb.BlockMetadataIndex_name), i.e. the block was constructed without the standard metadata slots (SIGNATURES, LAST_CONFIG, etc.).

Common situations: A leader assembling blocks without initializing metadata array; a custom/older block builder writing fewer metadata entries; deserialized/corrupted proposal missing metadata; mixing block formats from different fabric versions.

Related errors

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/0b0dbdfe8b66ed14. Report an issue: GitHub.