Stuck transactions - graceful handling?

[skgbanga]

Hello,

I noticed a weird thing in which sometimes (about ~1%) brownie says that it has sent a transaction, but then is just stuck. e.g.

Transaction sent: 0xtransaction_hash
<waiting>

I looked into the code a little bit, and noticed this while True loop.

    def _await_transaction(self, required_confs: int, is_blocking: bool) -> None:
        # await tx showing in mempool
        while True:
            try:
                tx: Dict = web3.eth.get_transaction(HexBytes(self.txid))
                break
            except (TransactionNotFound, ValueError):
                if self.sender is None:
                    # if sender was not explicitly set, this transaction was
                    # not broadcasted locally and so likely doesn't exist
                    raise
                if self.nonce is not None:
                    sender_nonce = web3.eth.get_transaction_count(str(self.sender))
                    if sender_nonce > self.nonce:
                        self.status = Status(-2)
                        return
                time.sleep(1)

According to the documentation here:
https://web3py.readthedocs.io/en/stable/web3.eth.html#web3.eth.Eth.get_transaction

it will throw TransactionNotFound if it hasn't been mined yet, and it seems we are handling few cases in the except clause.

I was wondering if these are exhaustive enough. i.e. could it be that some case is missing, and we can end up in an infinite loop here? Also does it make sense to have an upper limit of waiting here and maybe send a cancel for that transaction after that.

[skgbanga]

I spent more time to figure out what is going on. (since I was being affected by this problem quite badly).

When we do contract.foo(...), essentially we call web3.eth.send_transaction and then in TransactionReceipt init function, we keep calling web3.eth.get_transaction (as shown above) in a tight loop. (I added print statements in the code to verify this).

So most likely this is outside the scope of brownie, and in the realm of web3.eth

I am curious if there is anything we can do about this though. Any function we can call to figure out what is going on? (check for packet drop or something). Being stuck in a script is painful.