linera-io/linera-protocol · error

logs must be an RLP list

Error message

logs must be an RLP list

What it means

After skipping status, cumulative_gas_used and logs_bloom, decode_receipt_logs decodes the next RLP item — the logs array — and requires it to be a list (an array of log entries). If the bytes at that position decode as an RLP string instead (wrong field alignment, extra/missing fields, post-Byzantium vs pre-Byzantium receipt shape), this ensure! fails.

Source

Thrown at linera-bridge/src/proof/mod.rs:403

        alloy_rlp::Header::decode(&mut data).map_err(|e| anyhow!("invalid receipt RLP: {e}"))?;
    ensure!(list_header.list, "receipt must be an RLP list");

    // Limit reads to the receipt's declared payload.
    ensure!(
        data.len() >= list_header.payload_length,
        "receipt payload extends past available data"
    );
    let mut data = &data[..list_header.payload_length];

    // Skip: status (0), cumulative_gas_used (1), logs_bloom (2)
    for i in 0..3 {
        skip_rlp_item(&mut data).map_err(|e| anyhow!("failed to skip receipt field {i}: {e}"))?;
    }

    // Decode the logs list
    let logs_header =
        alloy_rlp::Header::decode(&mut data).map_err(|e| anyhow!("invalid logs list RLP: {e}"))?;
    ensure!(logs_header.list, "logs must be an RLP list");
    ensure!(
        data.len() >= logs_header.payload_length,
        "logs payload extends past receipt boundary"
    );

    let mut logs_data = &data[..logs_header.payload_length];
    let mut logs = Vec::new();
    while !logs_data.is_empty() {
        logs.push(decode_log(&mut logs_data)?);
    }

    Ok(logs)
}

/// Parses a `DepositInitiated` event from a receipt log.
///
/// Verifies that `topic[0]` matches the event signature, that the log was emitted by
/// the `expected_emitter` (bridge contract address), and ABI-decodes the data fields.

View on GitHub (pinned to 6c226ddcb3)

Solutions

1. Decode with a reference implementation (alloy_consensus::Receipt) to validate the bytes, then compare field-by-field
2. Rebuild test fixtures using real receipts fetched from RPC
3. Check that exactly three fields were skipped before the logs list

match decode_receipt_logs(bytes) {
    Ok(logs) => logs,
    Err(e) if e.to_string().contains("logs must be an RLP list") => {
        anyhow::bail!("receipt field misalignment: expected [status, gas, bloom, logs] list")
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: Receipts that skip fields this parser expects (e.g. pre-Byzantium root instead of status can still parse, but any variant with fewer than 4 fields misaligns); slicing bugs that leave the parser positioned on a non-list item; hand-built receipts with logs encoded as a string.

Common situations: Test vectors constructed field-by-field where the logs entry was RLP-encoded as a byte string; upstream changes to receipt field counts (new EIPs adding fields after logs would not matter, but fields before logs would); desynchronized offsets after manual prefix stripping.

Related errors

• logs payload extends past receipt boundary
• empty receipt RLP
• receipt must be an RLP list
• receipt payload extends past available data
• invalid logs list RLP: {e}

AI-assisted analysis of linera-io/linera-protocol@6c226ddcb3 (2026-08-22). Data as JSON: /api/errors/61c42f8bf49a3e62. Report an issue: GitHub.