feat(minor-voting-verifier)!: use transaction log index instead of bl…

…ock log index to identify EVM events (#314)

* feat(minor-voting-verifier)!: use transaction log index instead of block log index to identify EVM events

* Improve comments

Co-authored-by: Christian Gorenflo <[email protected]>

* replace cast with num_traits

---------

Co-authored-by: Christian Gorenflo <[email protected]>

ampd/src/evm/verifier.rs

@@ -3,6 +3,7 @@ use ethers::abi::{encode, Token};
 use ethers::contract::EthLogDecode;
 use ethers::prelude::abigen;
 use ethers::types::{Log, TransactionReceipt, H256};
+use num_traits::cast;
 
 use crate::handlers::evm_verify_msg::Message;
 use crate::handlers::evm_verify_worker_set::WorkerSetConfirmation;
@@ -19,7 +20,6 @@ impl PartialEq<IAxelarGatewayEventsWithLog<'_>> for &Message {
         match event {
             IAxelarGatewayEvents::ContractCallFilter(event) => {
                 log.transaction_hash == Some(self.tx_id)
-                    && log.log_index == Some(self.event_index.into())
                     && event.sender == self.source_address
                     && self.destination_chain == event.destination_chain
                     && event.destination_contract_address == self.destination_address
@@ -49,7 +49,6 @@ impl PartialEq<IAxelarGatewayEventsWithLog<'_>> for &WorkerSetConfirmation {
                     .unzip();
 
                 log.transaction_hash == Some(self.tx_id)
-                    && log.log_index == Some(self.event_index.into())
                     && event.new_operators_data
                         == encode(&[
                             Token::Array(operators),
@@ -69,12 +68,13 @@ fn has_failed(tx_receipt: &TransactionReceipt) -> bool {
 fn get_event<'a>(
     gateway_address: &EVMAddress,
     tx_receipt: &'a TransactionReceipt,
-    log_index: u64,
+    log_index: u32,
 ) -> Option<IAxelarGatewayEventsWithLog<'a>> {
+    let log_index: usize = cast(log_index).expect("log_index must be a valid usize");
+
     tx_receipt
         .logs
-        .iter()
-        .find(|log| log.log_index == Some(log_index.into()))
+        .get(log_index)
         .filter(|log| log.address == *gateway_address)
         .and_then(
             |log| match IAxelarGatewayEvents::decode_log(&log.clone().into()) {
@@ -89,7 +89,7 @@ fn verify<'a, V>(
     tx_receipt: &'a TransactionReceipt,
     to_verify: V,
     expected_transaction_hash: H256,
-    expected_event_index: u64,
+    expected_event_index: u32,
 ) -> Vote
 where
     V: PartialEq<IAxelarGatewayEventsWithLog<'a>>,
@@ -302,7 +302,7 @@ mod tests {
     fn get_matching_worker_set_and_tx_receipt(
     ) -> (EVMAddress, TransactionReceipt, WorkerSetConfirmation) {
         let tx_id = Hash::random();
-        let log_index = 999;
+        let log_index = 1;
         let gateway_address = EVMAddress::random();
 
         let worker_set = WorkerSetConfirmation {
@@ -353,7 +353,7 @@ mod tests {
 
     fn get_matching_msg_and_tx_receipt() -> (EVMAddress, TransactionReceipt, Message) {
         let tx_id = Hash::random();
-        let log_index = 999;
+        let log_index = 1;
         let gateway_address = EVMAddress::random();
 
         let msg = Message {

ampd/src/handlers/evm_verify_msg.rs

@@ -32,7 +32,7 @@ type Result<T> = error_stack::Result<T, Error>;
 #[derive(Deserialize, Debug)]
 pub struct Message {
     pub tx_id: Hash,
-    pub event_index: u64,
+    pub event_index: u32,
     pub destination_address: String,
     pub destination_chain: connection_router_api::ChainName,
     pub source_address: EVMAddress,

ampd/src/handlers/evm_verify_worker_set.rs

@@ -34,7 +34,7 @@ pub struct Operators {
 #[derive(Deserialize, Debug)]
 pub struct WorkerSetConfirmation {
     pub tx_id: Hash,
-    pub event_index: u64,
+    pub event_index: u32,
     pub operators: Operators,
 }
 

contracts/nexus-gateway/src/nexus.rs

@@ -25,6 +25,8 @@ pub struct Message {
 
 impl CustomMsg for Message {}
 
+// it's parsed into u64 instead of u32 (https://github.com/axelarnetwork/axelar-amplifier/blob/bf0b3049c83e540989c7dad1c609c7e2ef6ed2e5/contracts/voting-verifier/src/events.rs#L162)
+// here in order to match the message type defined in the nexus module. Changing nexus to use u32 instead is not worth the effort.
 fn parse_message_id(message_id: &str) -> Result<(nonempty::Vec<u8>, u64), ContractError> {
     // expected format: <tx_id>:<index>
     let components = message_id.split(ID_SEPARATOR).collect::<Vec<_>>();

contracts/voting-verifier/src/events.rs

@@ -112,13 +112,14 @@ impl From<PollStarted> for Event {
 #[cw_serde]
 pub struct WorkerSetConfirmation {
     pub tx_id: nonempty::String,
-    pub event_index: u64,
+    pub event_index: u32,
     pub operators: Operators,
 }
 
 impl WorkerSetConfirmation {
     pub fn new(message_id: nonempty::String, operators: Operators) -> Result<Self, ContractError> {
         let (tx_id, event_index) = parse_message_id(&message_id)?;
+
         Ok(Self {
             tx_id,
             event_index,
@@ -130,7 +131,7 @@ impl WorkerSetConfirmation {
 #[cw_serde]
 pub struct TxEventConfirmation {
     pub tx_id: nonempty::String,
-    pub event_index: u64,
+    pub event_index: u32,
     pub destination_address: Address,
     pub destination_chain: ChainName,
     pub source_address: Address,
@@ -160,7 +161,7 @@ impl TryFrom<Message> for TxEventConfirmation {
 
 fn parse_message_id(
     message_id: &nonempty::String,
-) -> Result<(nonempty::String, u64), ContractError> {
+) -> Result<(nonempty::String, u32), ContractError> {
     // expected format: <tx_id>:<index>
     let components = message_id.split(ID_SEPARATOR).collect::<Vec<_>>();
 
@@ -171,7 +172,7 @@ fn parse_message_id(
     Ok((
         components[0].try_into()?,
         components[1]
-            .parse::<u64>()
+            .parse()
             .map_err(|_| ContractError::InvalidMessageID(message_id.to_string()))?,
     ))
 }