hyperledger/fabric · error

proposal header cannot be nil

Error message

proposal header cannot be nil

What it means

ProposalToBlock converts a SmartBFT proposal into a common.Block; the proposal's Header field carries the ASN.1-encoded block header. An empty Header means the proposal is malformed and cannot be converted, so the conversion aborts immediately before any unmarshalling.

Source

Thrown at orderer/consensus/smartbft/signature.go:57

	return bytes
}

// AsBytes returns the message to sign
func (sig *Signature) AsBytes() []byte {
	msg2Sign := util.ConcatenateBytes(sig.OrdererBlockMetadata, sig.IdentifierHeader, sig.BlockHeader)
	return msg2Sign
}

// ProposalToBlock marshals the proposal the block
func ProposalToBlock(proposal types.Proposal) (*cb.Block, error) {
	// initialize block with empty fields
	block := &cb.Block{
		Data:     &cb.BlockData{},
		Metadata: &cb.BlockMetadata{},
	}

	if len(proposal.Header) == 0 {
		return nil, errors.New("proposal header cannot be nil")
	}

	hdr := &asn1Header{}

	if _, err := asn1.Unmarshal(proposal.Header, hdr); err != nil {
		return nil, errors.Wrap(err, "bad header")
	}

	block.Header = &cb.BlockHeader{
		Number:       hdr.Number.Uint64(),
		PreviousHash: hdr.PreviousHash,
		DataHash:     hdr.DataHash,
	}

	if len(proposal.Payload) == 0 {
		return nil, errors.New("proposal payload cannot be nil")
	}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Confirm the channel is configured with the SmartBFT consensus type and the proposal originates from SmartBFT (check consensus_type in channel config).
2. Re-pull/re-sync the proposal from correct peers (trigger synchronization) if the local data is corrupted.
3. Verify no code path passes a zero-value types.Proposal{} into the chain; initialize it from ViewChainer/Consensus state properly.
4. If upgrading from RAFT, ensure the chain was created with SmartBFT genesis settings rather than reusing RAFT artifacts.

Example fix

// before
block, err := signature.ProposalToBlock(types.Proposal{})

// after
if len(prop.Header) == 0 {
    return errors.New("refusing to convert empty proposal")
}
block, err := signature.ProposalToBlock(prop)

if prop == nil || len(prop.Header) == 0 {
    return fmt.Errorf("proposal has no header; cannot verify/convert")
}
block, err := ProposalToBlock(*prop)

func hasProposalHeader(p *types.Proposal) bool {
    return p != nil && len(p.Header) > 0
}

block, err := ProposalToBlock(prop)
if err != nil {
    if err.Error() == "proposal header cannot be nil" {
        // proposal source is invalid; re-fetch or resync
    }
    return err
}

When it happens

Trigger: Calling VerifyProposal, SignProposal, RequestsFromProposal, or Deliver with a types.Proposal whose Header byte slice is empty/nil — typically a proposal constructed by a different consensus implementation or corrupted during storage/transit.

Common situations: Mixing proposal data between RAFT (etcdraft) and SmartBFT channels; reading a corrupted proposal from the WAL/local ledger; a bug in custom consensus integration passing an uninitialized Proposal struct.

Related errors

• proposal payload cannot be nil
• consenter options type mismatch
• failed getting proposal context. Signed proposal is nil
• Invalid signed proposal during check policy on channel [%s]
• Failing extracting proposal during check policy on channel [

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/6bcb9339fe20cf73. Report an issue: GitHub.