hyperledger/fabric · error

error unmarshalling original config

Error message

error unmarshalling original config

What it means

proto.Unmarshal failed on the original config bytes: the data is not a valid wire-format common.Config message. The wrapper "error unmarshalling original config" distinguishes it from the updated-config equivalent.

Source

Thrown at cmd/configtxlator/main.go:202

	err = protolator.DeepMarshalJSON(output, msg)
	if err != nil {
		return errors.Wrapf(err, "error encoding output")
	}

	return nil
}

func computeUpdt(original, updated, output *os.File, channelID string) error {
	origIn, err := io.ReadAll(original)
	if err != nil {
		return errors.Wrapf(err, "error reading original config")
	}

	origConf := &cb.Config{}
	err = proto.Unmarshal(origIn, origConf)
	if err != nil {
		return errors.Wrapf(err, "error unmarshalling original config")
	}

	updtIn, err := io.ReadAll(updated)
	if err != nil {
		return errors.Wrapf(err, "error reading updated config")
	}

	updtConf := &cb.Config{}
	err = proto.Unmarshal(updtIn, updtConf)
	if err != nil {
		return errors.Wrapf(err, "error unmarshalling updated config")
	}

	cu, err := update.Compute(origConf, updtConf)
	if err != nil {
		return errors.Wrapf(err, "error computing config update")
	}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Ensure both inputs are binary protos of type common.Config (re-run decode/encode pipeline correctly)
2. Validate with protoc --decode_raw < orig.pb
3. Re-fetch the original config from the orderer and decode/encode it cleanly
4. Check that the file wasn't edited or truncated

Example fix

// before
configtxlator compute-update --original config.json --updated updated.json ...
// after
configtxlator encode --input config.json --output orig.pb --type common.Config && configtxlator encode --input updated.json --output updt.pb --type common.Config && configtxlator compute-update --original orig.pb --updated updt.pb ...

// verify original is binary common.Config, not JSON
head -c1 "$ORIGINAL" | grep -q '{' && echo "original is JSON; encode it first" && exit 1
protoc --decode_raw < "$ORIGINAL" > /dev/null || { echo "invalid proto"; exit 1; }

out, err := cmd.CombinedOutput()
if err != nil && strings.Contains(string(out), "error unmarshalling original config") {
    return fmt.Errorf("re-encode original with: configtxlator encode --type common.Config")
}

When it happens

Trigger: Original file is JSON instead of binary proto, was decoded/corrupted by a previous step, is truncated, or is a ConfigUpdate rather than a Config.

Common situations: Feeding config.json (output of decode) back into compute-update, partial downloads, or mixing artifacts from different Fabric channels/versions.

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

• error unmarshalling
• error unmarshalling updated config
• error encoding output
• 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/f8b405072acfe8aa. Report an issue: GitHub.