hyperledger/fabric · error

malformed block contents: %s

Error message

malformed block contents: %s

What it means

Returned by doInspectBlock when protolator.DeepMarshalJSON fails while rendering the unmarshaled block as JSON to stdout. It means the block parsed as protobuf but its contents (e.g. malformed nested messages) could not be serialized into the human-readable JSON form configtxgen prints.

Source

Thrown at cmd/configtxgen/main.go:93

	}
	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 {
		return fmt.Errorf("Error unmarshalling envelope: %s", err)
	}

	err = protolator.DeepMarshalJSON(os.Stdout, env)

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Inspect the wrapped error to see which protobuf field failed conversion
2. Obtain a clean copy of the block from a peer or orderer and re-inspect

When it happens

Trigger: Thrown at cmd/configtxgen/main.go:93 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/34da9faaf93b49d6. Report an issue: GitHub.