hyperledger/fabric · error

error marshaling computed config update

Error message

error marshaling computed config update

What it means

computeUpdt in the configtxlator tool marshals the computed protobuf ConfigUpdate to bytes before writing to the output file. If proto.Marshal fails on the ConfigUpdate, this wrapped error is returned and configtxlator output computation aborts. proto.Marshal should rarely fail unless the message contains unmarshalable state (e.g. required proto2 fields unset, or nil message with required fields).

Source

Thrown at cmd/configtxlator/main.go:225

		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")
	}

	cu.ChannelId = channelID

	outBytes, err := proto.Marshal(cu)
	if err != nil {
		return errors.Wrapf(err, "error marshaling computed config update")
	}

	_, err = output.Write(outBytes)
	if err != nil {
		return errors.Wrapf(err, "error writing config update to output")
	}

	return nil
}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Verify both input config blocks are from the same channel and valid protobufs (decode them with configtxlator decode first).
2. Check the wrapped inner error in the log to identify which field failed marshaling.
3. Re-export the config blocks from a live orderer (fetch config block) instead of reusing cached files.
4. Rebuild configtxlator to match your fabric protos version.

Example fix

null

// validate inputs before compute-update
for _, f := range []string{originalPath, updatedPath} {
    b, err := os.ReadFile(f)
    if err != nil { log.Fatalf("cannot read %s: %v", f, err) }
    var cb common.Config
    if err := proto.Unmarshal(b, &cb); err != nil {
        log.Fatalf("%s is not a valid protobuf Config: %v", f, err)
    }
}

When it happens

Trigger: Running 'configtxlator compute-update' where the generated ConfigUpdate protobuf cannot be marshaled — typically a nil or malformed ConfigUpdate, or corrupted intermediate config data produced by mismatched input config blocks.

Common situations: Feeding config blocks from different channels into configtxlator; corrupted or truncated config block protobufs; custom/modified config proto extensions that are invalid; using output from an earlier failed decode step.

Related errors

• error marshaling
• error encode input
• message of type %s unknown
• error marshaling: proto: Marshal called with nil
• error unmarshalling

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/af896ba67ba472f3. Report an issue: GitHub.