hyperledger/fabric · error

block ID illegal, cannot be empty

Error message

block ID illegal, cannot be empty

What it means

ValidateFetchBlockID checks the block identifier given to the channel participation fetch-block endpoint. This error means the caller supplied an empty block ID string; valid IDs are 'newest', 'oldest', 'config', or a numeric block number.

Source

Thrown at orderer/common/channelparticipation/validator.go:113

	configUpdateEnv, err := protoutil.EnvelopeToConfigUpdate(env)
	if err != nil {
		return "", err
	}

	configUpdate, err := configtx.UnmarshalConfigUpdate(configUpdateEnv.ConfigUpdate)
	if err != nil {
		return "", err
	}

	return configUpdate.ChannelId, nil
}

// ValidateFetchBlockID checks the block id. He can be: newest|oldest|config|(number)
func ValidateFetchBlockID(blockID string) error {
	// Length
	if len(blockID) <= 0 {
		return errors.Errorf("block ID illegal, cannot be empty")
	}

	if blockID == "newest" || blockID == "oldest" || blockID == "config" {
		return nil
	}

	_, err := strconv.Atoi(blockID)
	if err == nil {
		return nil
	}

	return errors.Errorf("'%s' not equal <newest|oldest|config|(number)>", blockID)
}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Supply a valid block ID: 'newest', 'oldest', 'config', or a non-negative integer (e.g. 0, 42).
2. Fix the shell script so the variable holding the block ID is not empty (add a default, e.g. blockID=${BLOCK_ID:-newest}).
3. Check the client library call signature — the block ID argument is mandatory, not optional.
4. URL-encode the path correctly so a literal value is delivered rather than an empty segment.

Example fix

// before
curl .../channels/mychannel/blocks/$BLOCK_ID   # BLOCK_ID unset -> empty
// after
BLOCK_ID=${BLOCK_ID:-newest}
curl .../channels/mychannel/blocks/$BLOCK_ID

if blockID == "" {
    return errors.New("block ID is required: newest|oldest|config|(number)")
}

if err := channelparticipation.ValidateFetchBlockID(blockID); err != nil {
    return fmt.Errorf("invalid block ID %q: %w", blockID, err)
}

When it happens

Trigger: Calling GET /participation/v1/channels/{channel}/blocks with an empty path/query parameter, or invoking the CLI/SDK fetch helper without the blockID argument populated.

Common situations: Unset shell variable used as the block ID in a curl/CLI command; UI leaving the field blank; API client that omits an optional-looking parameter that is actually required.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• '%s' not equal <newest|oldest|config|(number)>
• cannot enable channel capabilities without orderer support f
• Must set some OrdererAddresses
• failed computing orderer addresses
• orderer is required, but no ordering endpoint or endorser cl

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/7ef93d4b831ccf53. Report an issue: GitHub.