Confusion about connectionOpenAck in IBCConnection.sol

[michwqy]

I found that connection.state allowed to be INIT or TRYOPEN in connectionOpenAck function of contracts/core/03-connection/IBCConnection.sol. I don't understand when connection.state is TRYOPEN and connectionOpenAck can be executed successfully. Since connectionOpenAck requires counterparty connection in TRYOPEN state, connectionOpenTry requires conterparty connection in INIT state and there is no way that connection can go to TRYOPEN from INIT, I think connectionOpenAck can't be executed successfully if connection.state is TRYOPEN. Is there any purpose I don't understand?

[bluele]

Thank you for opening an issue.

In conclusion, this is a bug.

In previous versions(e.g. v1.0.0) of ibc-go, it was possible for a chain that executed ConnOpenInit to execute ConnOpenTry by referencing a previous connection. Consequently, there could be both INIT and TRY_OPEN as a previous connection state on ConnOpenAck.

However, the latest ics-03 does not support referencing a previous connection on ConnOpenTry, so only INIT should be allowed as a previous state on ConnOpenACK. Therefore, ibc-solidity needs to be fixed in the same way.

[michwqy]

Thanks for your reply.