hyperledger/fabric · error

error unmarshalling ChaincodeAction

Error message

error unmarshalling ChaincodeAction

What it means

Returned by protoutil.UnmarshalChaincodeAction when proto.Unmarshal fails to decode bytes into a peer.ChaincodeAction. The wrap adds message-type context to the underlying protobuf error. It means the action bytes (typically ProposalResponsePayload.Extension or the transaction action's results) are invalid or of the wrong type.

Source

Thrown at protoutil/unmarshalers.go:123

// UnmarshalChaincodeHeaderExtension unmarshals bytes to a ChaincodeHeaderExtension
func UnmarshalChaincodeHeaderExtension(hdrExtension []byte) (*peer.ChaincodeHeaderExtension, error) {
	chaincodeHdrExt := &peer.ChaincodeHeaderExtension{}
	err := proto.Unmarshal(hdrExtension, chaincodeHdrExt)
	return chaincodeHdrExt, errors.Wrap(err, "error unmarshalling ChaincodeHeaderExtension")
}

// UnmarshalProposalResponse unmarshals bytes to a ProposalResponse
func UnmarshalProposalResponse(prBytes []byte) (*peer.ProposalResponse, error) {
	proposalResponse := &peer.ProposalResponse{}
	err := proto.Unmarshal(prBytes, proposalResponse)
	return proposalResponse, errors.Wrap(err, "error unmarshalling ProposalResponse")
}

// UnmarshalChaincodeAction unmarshals bytes to a ChaincodeAction
func UnmarshalChaincodeAction(caBytes []byte) (*peer.ChaincodeAction, error) {
	chaincodeAction := &peer.ChaincodeAction{}
	err := proto.Unmarshal(caBytes, chaincodeAction)
	return chaincodeAction, errors.Wrap(err, "error unmarshalling ChaincodeAction")
}

// UnmarshalResponse unmarshals bytes to a Response
func UnmarshalResponse(resBytes []byte) (*peer.Response, error) {
	response := &peer.Response{}
	err := proto.Unmarshal(resBytes, response)
	return response, errors.Wrap(err, "error unmarshalling Response")
}

// UnmarshalChaincodeEvents unmarshals bytes to a ChaincodeEvent
func UnmarshalChaincodeEvents(eBytes []byte) (*peer.ChaincodeEvent, error) {
	chaincodeEvent := &peer.ChaincodeEvent{}
	err := proto.Unmarshal(eBytes, chaincodeEvent)
	return chaincodeEvent, errors.Wrap(err, "error unmarshalling ChaicnodeEvent")
}

// UnmarshalProposalResponsePayload unmarshals bytes to a ProposalResponsePayload
func UnmarshalProposalResponsePayload(prpBytes []byte) (*peer.ProposalResponsePayload, error) {

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Verify you pass the correct field (ChaincodeAction lives in ProposalResponsePayload.Extension / Action.Results), not the parent payload bytes.
2. Check for empty/truncated results before unmarshaling and fail fast with context.
3. Ensure the transaction was produced by a Fabric version compatible with your parser.
4. Validate the parent structures first (Envelope -> Payload -> Transaction -> Action) to ensure field offsets are right.
5. Log length and base64 of failing bytes to diagnose corruption.

Example fix

// before
action, _ := protoutil.UnmarshalChaincodeAction(prpBytes) // parent payload, wrong bytes
// after
prp, _ := protoutil.UnmarshalProposalResponsePayload(prpBytes)
action, err := protoutil.UnmarshalChaincodeAction(prp.Extension)
if err != nil {
    return fmt.Errorf("bad chaincode action: %w", err)
}

func validChaincodeAction(prp *peer.ProposalResponsePayload) bool {
    return prp != nil && len(prp.Extension) > 0
}

func isChaincodeAction(v any) bool {
    _, ok := v.(*peer.ChaincodeAction)
    return ok
}

action, err := protoutil.UnmarshalChaincodeAction(prp.Extension)
if err != nil {
    return fmt.Errorf("cannot extract chaincode action: %w", err)
}

When it happens

Trigger: Calling UnmarshalChaincodeAction on results fields that are empty, truncated, or actually another message type; reached from transaction validation (extractDependenciesForTx, ValidateLSCCInvocation), read-write set extraction, and CLI invoke/query flows.

Common situations: Parsing committed transactions from blocks where the action payload was produced by a different Fabric version; extracting rwset bytes from the wrong field; corrupted transaction records.

Understand the failure class

Background: "cannot parse invalid wire-format data", "cannot unmarshal", "failed unmarshalling": protobuf unmarshal errors explained — this error's family across 10 libraries.

Related errors

• GetProposalResponsePayload error %s
• GetChaincodeAction error %s
• error unmarshalling ChaincodeHeaderExtension
• error unmarshalling Response
• error unmarshalling ChaicnodeEvent

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/3f950822956977d0. Report an issue: GitHub.