rndlabs/cowswap-twap-orders

🐄🐮 Time-weighted average price orders for CoW Protocol

cowswap-twap-orders's Issues

feat: action reversion handling

Problem
Naively polling every block for a tradeable order is not required with ConditionalOrders that have some defined payload. This is because the payload itself relates to the order and can be used to determine beforehand if there should be some tradeability (unless specific on-chain state is checked by the respective ConditionalOrder).

Solution
When watching for orders, we take advantage of custom errors passed on reversion:

1. If reverted with OrderCancelled, delete it from storage.
2. If reverted with OrderExpired, delete it from storage.
3. If reverted with OrderNotValid, skip processing in this block (likely a result of a span).

Tasks

• Implement reversion handling

Typo in build command

You build command goes like this:
"build": "forge buid && yarn build:actions && yarn build:cli",

Shouldn't it be:
"build": "forge build && yarn build:actions && yarn build:cli",

feat: remember order broadcast

Problem
Naively watching for orders and sending these to the API will result in multiple submissions of the same order. As CoW Protocol protects against this by monitoring the fill of each orderUid, this doesn't cause multiple executions, however it consumes resources for API submissions.

Solution
Remember the orderUids that are submitted. If an order has been previously submitted, don't submit it again. Implement a fill watch action that purges filled orderUids from the storage.

Tasks

• Modify Registry layout to include status a Map with key of keccak256(getTradeableOrder(payload)) and value corresponding to an enum of either SUBMITTED or FILLED.
• If order is SUBMITTED, don't attempt to submit again to CoW Protocol.

feat: action performance

Problem
It is a little difficult to monitor all the parts of an order (TWAP) to see see what the fill rate was like.

Solution
Using the status from #2 if the order becomes OrderCancelled or OrderExpired, we can generate a report.

Tasks

• On OrderCancelled or OrderExpired, generate a report of the number of parts that were filled / not filled.

Allow variable signature length

I really like the changes that were made compared to the framework in https://github.com/cowprotocol/conditional-smart-orders as they allow more effective creation of smart orders and also make it easier to leave the Safe functional!

One decision I find difficult however, for general purpose smart orders is to require fixed length signatures. There are definitely use cases (e.g. dynamic price checkers for milkman style orders) where the same order type may have different lengths signatures.

Maybe we can define a magic value that indicates "arbitrary length" to avoid failing this check:

cowswap-twap-orders/src/CoWFallbackHandler.sol

Line 66 in 864546a

if (_signature.length == CONDITIONAL_ORDER_BYTES_LENGTH() && verifyTrade(_dataHash, _signature)) {