{"record":{"id":"db0e5ccc433de65a","repo":"nautechsystems/nautilus_trader","slug":"invalid-event-signature-for-event-name-expect-db0e5c","errorCode":null,"errorMessage":"Invalid event signature for '{event_name}': expected {expected_hash}, was {actual_hex}","messagePattern":"Invalid event signature for '(.+?)': expected (.+?), was (.+?)","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/adapters/blockchain/src/rpc/log.rs","lineNumber":180,"sourceCode":"}\n\n/// Validate event signature from topic0.\n///\n/// The first topic (topic0) of an Ethereum event log contains the keccak256 hash\n/// of the event signature. This function validates that the actual signature\n/// matches the expected one.\n///\n/// # Errors\n///\n/// Returns an error if the signature doesn't match or topic0 is missing.\npub fn validate_event_signature(\n    log: &RpcLog,\n    expected_hash: &str,\n    event_name: &str,\n) -> anyhow::Result<()> {\n    let sig_bytes = extract_topic_bytes(log, 0)?;\n    let actual_hex = hex::encode(&sig_bytes);\n    anyhow::ensure!(\n        actual_hex == expected_hash,\n        \"Invalid event signature for '{event_name}': expected {expected_hash}, was {actual_hex}\",\n    );\n    Ok(())\n}\n\n#[cfg(test)]\nmod tests {\n    use rstest::{fixture, rstest};\n\n    use super::*;\n\n    /// Real RPC log from Arbitrum PoolCreated event at block 185\n    /// Pool: 0xB9Fc136980D98C034a529AadbD5651c087365D5f\n    /// token0: 0x2E5353426C89F4eCD52D1036DA822D47E73376C4\n    /// token1: 0x838930cFE7502dd36B0b1ebbef8001fbF94f3bFb\n    /// fee: 3000, tickSpacing: 60\n    #[fixture]","sourceCodeStart":162,"sourceCodeEnd":198,"githubUrl":"https://github.com/nautechsystems/nautilus_trader/blob/18893faf8b356be3320add8de2f861b0b647cf06/crates/adapters/blockchain/src/rpc/log.rs#L162-L198","documentation":"validate_event_signature checks that the first topic (topic0) of an RPC log matches the expected keccak256 event signature hash for a named event. When the hex-encoded topic0 differs from the expected hash, anyhow::ensure! aborts with this error naming the event, expected hash, and actual hex. It guards against decoding a log emitted by a different event or contract version.","triggerScenarios":"Calling validate_event_signature with an RpcLog whose topic0 does not equal the provided expected_hash string. This happens when the log is from a different event than claimed, the expected_hash is computed with the wrong signature text (wrong param types/order), the hash is not lowercase hex of the correct 32 bytes, or the log genuinely has no/misaligned topic0.","commonSituations":"ABI signature drift after a contract upgrade or event parameter change; hand-writing the signature string (e.g. 'Transfer(...)') with wrong parameter types so the keccak hash differs; comparing against a checksummed or 0x-prefixed hash while hex::encode produces plain lowercase hex; subscribing to logs where anonymous or overloaded events share topics.","solutions":["Recompute the expected hash with keccak256 over the exact canonical signature string (correct event name, parameter types, order, no spaces) and compare that.","Verify the expected_hash matches hex::encode output format: 64 lowercase hex chars with no 0x prefix; normalize both sides before comparing if needed.","Confirm the RpcLog actually came from the event/contract you expect (check address and topic count) before validating.","If event definitions changed in a new contract version, update the stored signature hashes rather than forcing the old hash."],"exampleFix":"// before\nlet expected = \"0xDDF252AD1BE2C89B69C2B068FC378DAA952BA7F163C4A11628F55A4DF523B3EF\";\nvalidate_event_signature(&log, expected, \"Transfer\")?;\n// after\nlet expected = \"ddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef\"; // lowercase, no 0x, canonical signature\nvalidate_event_signature(&log, expected, \"Transfer\")?;","handlingStrategy":"validation","validationCode":"fn is_valid_event_signature(log_topic0: &str, expected: &str) -> bool {\n    let norm = |s: &str| s.trim_start_matches(\"0x\").to_ascii_lowercase();\n    log_topic0.len() == 64 && expected.len() == 64 && norm(log_topic0) == norm(expected)\n}","typeGuard":null,"tryCatchPattern":"match validate_event_signature(&log, expected_hash, event_name) {\n    Ok(()) => { /* proceed with decoding */ }\n    Err(e) => { warn!(\"event signature mismatch: {e}\"); /* skip or route log */ }\n}","preventionTips":["Generate signature hashes programmatically with keccak256 over the canonical ABI signature, never by hand.","Store expected hashes as lowercase hex without the 0x prefix to match hex::encode output.","Re-verify hashes after any contract upgrade or ABI change.","Check the emitting contract address alongside the signature."],"tags":["blockchain","validation","hex","event-signature"],"backgroundTag":"checksum-mismatch","analyzedSha":"18893faf8b356be3320add8de2f861b0b647cf06","analyzedAt":"2026-09-08T20:49:34.690Z","contentChangedAt":"2026-09-08T20:49:34.690Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}