hyperledger/fabric · error

nil header

Error message

nil header

What it means

validateCommonHeader validates the common Header of a transaction and returns its parsed ChannelHeader and SignatureHeader. If the entire Header pointer is nil there is nothing to validate, so it returns this error before any field-level checks.

Source

Thrown at core/common/validation/msgvalidation.go:122

	// TODO: validate channelID in cHdr.ChannelID

	// Validate epoch in cHdr.Epoch
	// Currently we enforce that Epoch is 0.
	// TODO: This check will be modified once the Epoch management
	// will be in place.
	if cHdr.Epoch != 0 {
		return errors.Errorf("invalid Epoch in ChannelHeader. Expected 0, got [%d]", cHdr.Epoch)
	}

	// TODO: Validate version in cHdr.Version

	return nil
}

// checks for a valid Header
func validateCommonHeader(hdr *common.Header) (*common.ChannelHeader, *common.SignatureHeader, error) {
	if hdr == nil {
		return nil, nil, errors.New("nil header")
	}

	chdr, err := protoutil.UnmarshalChannelHeader(hdr.ChannelHeader)
	if err != nil {
		return nil, nil, err
	}

	shdr, err := protoutil.UnmarshalSignatureHeader(hdr.SignatureHeader)
	if err != nil {
		return nil, nil, err
	}

	err = validateChannelHeader(chdr)
	if err != nil {
		return nil, nil, err
	}

	err = validateSignatureHeader(shdr)

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Always populate Payload.Header (ChannelHeader + SignatureHeader) before signing and submitting the envelope
2. Check the client transaction-builder flow to ensure header assembly errors abort submission instead of producing a header-less payload
3. Fix test fixtures to construct a full Header via protoutil helpers
4. Validate envelope structure client-side (payload.Header != nil) before submit for clearer errors

Example fix

// before
payload := &common.Payload{Data: cceBytes} // Header missing
// after
payload := &common.Payload{Header: &common.Header{ChannelHeader: chdrBytes, SignatureHeader: shdrBytes}, Data: cceBytes}

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

func headerReady(payload *common.Payload) bool {
    return payload != nil && payload.Header != nil &&
        len(payload.Header.ChannelHeader) > 0 && len(payload.Header.SignatureHeader) > 0
}

if err != nil && err.Error() == "nil header" {
    // payload.Header was nil: rebuild envelope with a complete Header before resubmitting
}

When it happens

Trigger: ValidateTransaction or validateEndorserTransaction called with a payload whose Header is nil — typically when Payload.Header was never set in the envelope, or a test passes a nil header directly to validateCommonHeader.

Common situations: Clients building envelopes without attaching a Header; protobuf deserialization leaving Header nil for truncated payloads; test fixtures with minimal Payload structs; code paths that skip header assembly on error without aborting.

Related errors

• invalid chaincode deployment spec
• nil arguments
• '%s' not equal <newest|oldest|config|(number)>
• unmarshalling block: %s
• specified --channelID %s does not match channel ID %s in con

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/c874cb4fd7f993cb. Report an issue: GitHub.