hyperledger/fabric · error

failed to unmarshal proposal response's response payload as

Error message

failed to unmarshal proposal response's response payload as type %T

What it means

printResponseAsJSON takes the payload from the endorser's proposal response and unmarshals it into the expected protobuf message type. If proto.Unmarshal fails — the bytes are not a valid encoding of the given msg type — the error is wrapped with this message including the Go type (%T).

Source

Thrown at internal/peer/lifecycle/chaincode/common.go:125

	return policyBytes, nil
}

func createCollectionConfigPackage(collectionsConfigFile string) (*pb.CollectionConfigPackage, error) {
	var ccp *pb.CollectionConfigPackage
	if collectionsConfigFile != "" {
		var err error
		ccp, _, err = chaincode.GetCollectionConfigFromFile(collectionsConfigFile)
		if err != nil {
			return nil, errors.WithMessagef(err, "invalid collection configuration in file %s", collectionsConfigFile)
		}
	}
	return ccp, nil
}

func printResponseAsJSON(proposalResponse *pb.ProposalResponse, msg proto.Message, out io.Writer) error {
	err := proto.Unmarshal(proposalResponse.Response.Payload, msg)
	if err != nil {
		return errors.Wrapf(err, "failed to unmarshal proposal response's response payload as type %T", msg)
	}

	bytes, err := json.MarshalIndent(msg, "", "\t")
	if err != nil {
		return errors.Wrap(err, "failed to marshal output")
	}

	fmt.Fprintf(out, "%s\n", string(bytes))

	return nil
}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Verify peer and CLI are on compatible fabric versions (lifecycle API mismatch)
2. Inspect the wrapped error for the unmarshal cause and hex-dump the payload if debugging a custom endorser
3. Retry against the correct endorser/peer (ensure not hitting an unexpected service on that host:port)

Example fix

// before
resp from mismatched peer (fabric 1.4 style payload)
// after
upgrade peer to fabric 2.x so QueryApprovedChaincodeDefinition payloads match the expected proto message

if len(proposalResponse.Response.Payload) == 0 {
    return errors.New("endorser returned empty payload")
}

if err := printResponseAsJSON(resp, msg, out); err != nil {
    if strings.Contains(err.Error(), "failed to unmarshal proposal response's response payload") {
        // check peer/CLI fabric version compatibility
    }
    return err
}

When it happens

Trigger: Lifecycle commands (Approve/Commit/Get/Query etc.) receive a proposal response whose Response.Payload bytes cannot be decoded into the expected message (e.g. QueryInstalledChaincodesResult, ApproveChaincodeDefinitionResult).

Common situations: Peer at an incompatible fabric version returning a different payload schema; a proxy/middleware altering or truncating payloads; custom endorser returning non-protobuf bytes.

Related errors

• error unmarshalling
• error unmarshalling original config
• error unmarshalling updated config
• failed to unmarshal ApplicationPolicy bytes
• could not unmarshal signature policy envelope

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/d5619d4c83832f32. Report an issue: GitHub.