hyperledger/fabric · error

error unmarshalling to block: %s

Error message

error unmarshalling to block: %s

What it means

Returned by configtxgen's doInspectBlock when protoutil.UnmarshalBlock fails on the bytes read from the file passed to -inspectBlock. It fires when the file content is not a valid protobuf-encoded Fabric block (e.g. a JSON file, a channel-create tx instead of a block, a truncated/corrupt file), so the block cannot be decoded for JSON dumping.

Source

Thrown at cmd/configtxgen/main.go:89

	logger.Info("Writing new channel tx")
	err = writeFile(outputChannelCreateTx, protoutil.MarshalOrPanic(configtx), 0o640)
	if err != nil {
		return fmt.Errorf("error writing channel create tx: %s", err)
	}
	return nil
}

func doInspectBlock(inspectBlock string) error {
	logger.Info("Inspecting block")
	data, err := os.ReadFile(inspectBlock)
	if err != nil {
		return fmt.Errorf("could not read block %s", inspectBlock)
	}

	logger.Info("Parsing genesis block")
	block, err := protoutil.UnmarshalBlock(data)
	if err != nil {
		return fmt.Errorf("error unmarshalling to block: %s", err)
	}
	err = protolator.DeepMarshalJSON(os.Stdout, block)
	if err != nil {
		return fmt.Errorf("malformed block contents: %s", err)
	}
	return nil
}

func doInspectChannelCreateTx(inspectChannelCreateTx string) error {
	logger.Info("Inspecting transaction")
	data, err := os.ReadFile(inspectChannelCreateTx)
	if err != nil {
		return fmt.Errorf("could not read channel create tx: %s", err)
	}

	logger.Info("Parsing transaction")
	env, err := protoutil.UnmarshalEnvelope(data)
	if err != nil {

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Verify the file passed to -inspectBlock was produced by configtxgen -outputBlock (or is a raw block from the ledger), not a channel creation tx or JSON export
2. Inspect the file with `file`/`xxd` to confirm it is binary protobuf and not empty or truncated
3. Regenerate the block with configtxgen using the same profile and retry the inspection

When it happens

Trigger: Thrown at cmd/configtxgen/main.go:89 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/003e6b702dec3fbb. Report an issue: GitHub.