feat: finalize *tokenless* HubPool CCTP messages #2270
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Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
grasphoper
changed the title
DepositForBurn messagesSigned-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
grasphoper
requested review from
mrice32,
nicholaspai,
pxrl,
james-a-morris,
dohaki and
bmzig
as code owners
…ng status Signed-off-by: Ihor Farion <[email protected]>
…ying on cctpMessageIndex Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
…or pending attestations ... Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
| let lastMessageSentEventIdx = -1; | ||
| receipt.logs.forEach((log, i) => { | ||
| if (_isMessageSentEvent(log)) { | ||
| if (lastMessageSentEventIdx == -1) { | ||
| lastMessageSentEventIdx = i; | ||
| } else { | ||
| _addCommonMessageEventIfRelevant(receipt.logs[lastMessageSentEventIdx]); | ||
| lastMessageSentEventIdx = i; | ||
| } | ||
| } else { | ||
| const depositForBurnVersion = _getDepositForBurnVersion(log); | ||
| if (depositForBurnVersion == -1) { | ||
| // Skip non-`DepositForBurn` events | ||
| return; | ||
| } | ||
| if (lastMessageSentEventIdx == -1) { | ||
| throw new Error( | ||
| "DepositForBurn event found without corresponding MessageSent event. " + | ||
| "Each DepositForBurn event must have a preceding MessageSent event in the same transaction. " + | ||
| `Transaction: ${receipt.transactionHash}, DepositForBurn log index: ${i}` | ||
| ); | ||
| } |
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Can you comment on what this loop is doing?
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Sure. Here, we go one by one over a receipts that we "suspect might have CCTP messages for finalization".
It's important to understand what we're looking for in the logs. It's either of 2 things:
MessageSent+DepositForBurn== a single USDC transfer from one chain to another (1)- solo
MessageSentwith noDepositForBurn-> a single crosschain message (2)
Then for each receipt we traverse all logs in order, and keep the latest encountered MessageSent index in lastMessageSentEventIdx . Then if we encounter next MessageSent -> the one stored in lastMessageSentEventIdx was (2). If we encounter DepositForBurn, then we bundle stored lastMessageSentEventIdx with it to receive (1)
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Is it fair to expect that a DepositForBurn event always follows a MessageSent event? If so, I'm wondering if we could first identify all DepositForBurn events and then use their logIndex fields for a subsequent pass over MessageSent events. If a MessageSent event has a logIndex that immediately precedes a DepositForBurn event then it'd be excluded. Could that work? (Motivation for this would be a bit less nesting, at the expense of additional loops - but I think it should be possible to do that in quite compact and concise code).
Also curious about some lines like 351 & 354 - it seems lastMessageSentEventIdx = i is performed unconditionally because it sits on either side of the if statement. Is that intended?
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If a MessageSent event has a logIndex that immediately precedes a DepositForBurn event then it'd be excluded. Could that work?
I'm a bit hesitant to do that beacuse I'm not 100% it's always the "one-before" index. Probably should be the case, but prev. impl. just relied smth like findLast(messageSent, starting_from_depositFrom_idx), so I kept that logic
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lastMessageSentEventIdx = i is performed unconditionally because it sits on either side of the if statement. Is that intended?
It is yeah:
if lastMessageSentEventIdx == -1: we don't have any preceding "unmatched"(not a part ofMessageSent+DepositForBurnsequence)MessageSentevents. We want to "remember" this event to process it later, so setlastMessageSentEventIdx = ielse: we do already have a precedingMessageSentevent that is "unmatched". This means that event atlastMessageSentEventIdxis a 'solo event' -> tokenless message. We process it by calling_addCommonMessageEventIfRelevantand update ourlastMessageSentEventIdxto point at our currentMessageSentevent instead
Does this make sense?
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Signed-off-by: Ihor Farion <[email protected]>
Current implementation of CCTP finalizer is only tracking
DepositForBurnevents, and thus is not considering other types of CCTP messages. CCTP can send tokenless messages viaMessageTransmittercontract, which emitsMessageSent(bytes message)event.We use
HubPooleventsTokensRelayedandMessageRelayedto find relevant tx hashes to search for suchMessageTransmitterMessageSentevents in addition to allDepositForBurnevents.