hyperledger/fabric · error

channel config found nil

Error message

channel config found nil

What it means

GenerateSimulationResults processes a transaction payload of type HeaderType_CONFIG during ledger simulation. The CONFIG payload's Data field is nil, so the channel config cannot be stored under the peer namespace; this sentinel error is returned.

Source

Thrown at core/peer/configtx_processor.go:38

	channelConfigKey = "CHANNEL_CONFIG_ENV_BYTES"
	peerNamespace    = ""
)

// ConfigTxProcessor implements the interface 'github.com/hyperledger/fabric/core/ledger/customtx/Processor'
type ConfigTxProcessor struct{}

// GenerateSimulationResults implements function in the interface 'github.com/hyperledger/fabric/core/ledger/customtx/Processor'
// This implementation processes CONFIG transactions which simply stores the config-envelope-bytes
func (tp *ConfigTxProcessor) GenerateSimulationResults(txEnv *common.Envelope, simulator ledger.TxSimulator, initializingLedger bool) error {
	payload := protoutil.UnmarshalPayloadOrPanic(txEnv.Payload)
	channelHdr := protoutil.UnmarshalChannelHeaderOrPanic(payload.Header.ChannelHeader)
	txType := common.HeaderType(channelHdr.GetType())

	switch txType {
	case common.HeaderType_CONFIG:
		peerLogger.Debugf("Processing CONFIG")
		if payload.Data == nil {
			return errors.New("channel config found nil")
		}
		return simulator.SetState(peerNamespace, channelConfigKey, payload.Data)
	default:
		return fmt.Errorf("tx type [%s] is not expected", txType)
	}
}

func retrieveChannelConfig(queryExecuter ledger.QueryExecutor) (*common.Config, error) {
	configBytes, err := queryExecuter.GetState(peerNamespace, channelConfigKey)
	if err != nil {
		return nil, err
	}
	if configBytes == nil {
		return nil, nil
	}
	configEnvelope := &common.ConfigEnvelope{}
	if err := proto.Unmarshal(configBytes, configEnvelope); err != nil {
		return nil, err

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Ensure the CONFIG payload's Data contains the marshaled common.Config before calling GenerateSimulationResults.
2. Regenerate the channel creation/config transaction (e.g., via configtxgen) instead of hand-crafting the envelope.
3. Validate payload != nil and payload.Data != nil upstream before invoking the processor.
4. If from a fetched block, re-fetch the config block — the stored envelope may be corrupt.

Example fix

// before
payload := &common.Payload{Header: hdr} // Data nil
sim.GenerateSimulationResults(payload)
// after
cfgBytes, _ := proto.Marshal(config)
payload := &common.Payload{Header: hdr, Data: cfgBytes}
sim.GenerateSimulationResults(payload)

if payload == nil || payload.Data == nil {
  return errors.New("CONFIG payload data is nil")
}

func hasConfigData(p *common.Payload) bool {
  return p != nil && p.Data != nil
}

if err := sim.GenerateSimulationResults(payload); err != nil && err.Error() == "channel config found nil" {
  return fmt.Errorf("malformed CONFIG payload: %w", err)
}

When it happens

Trigger: Calling GenerateSimulationResults with a txsim payload whose header type is CONFIG but whose Data byte slice is nil — i.e., a malformed/empty config payload passed to the processor.

Common situations: Constructing test config transactions manually and forgetting to serialize the Config message into payload.Data; a corrupted or truncated envelope that lost its data during channel creation; tooling that builds payloads programmatically (configtxgen-like flows).

Related errors

• tx type [%s] is not expected
• organization %s not found
• error decoding the block number
• error decoding the data hash
• error decoding the previous hash

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/842c9d527e6e7acb. Report an issue: GitHub.