execution reverted (close_position not executing the "Burn" call on Polygon network)

[carlos-pansela]

Describe the bug

close_position not executing the "Burn" function on Polygon network.

web3.exceptions.ContractLogicError ! execution reverted: Not cleared

The “Decrease Liquidity” and “Collect” parts of the function call execute fine, but the “Burn” call fails.

After running the close_position() a second time returns

web3.exceptions.ContractLogicError ! execution reverted

To Reproduce

I am unfortunately unable to reproduce this on demand. It seems to sometimes happens. I anecdotally suspect this happens when polygon network is overloaded but have no proof that it is the case.

Network: Polygon Mainnet

LP pool = 0x86f1d8390222A3691C28938eC7404A1661E618e0
token0 = 0x0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270
token1 = 0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619

Route: I don't have any custom route setup

Here is the relevant code

`
w3 = Web3(Web3.HTTPProvider(HTTPprovider))
w3.middleware_onion.inject(geth_poa_middleware, layer = 0)
w3.middleware_onion.add(construct_sign_and_send_raw_middleware(private_key))

version = 3
uniswap = Uniswap(address = address, private_key = private_key, version = version, provider = HTTPprovider, web3 = w3)

def close_position(token_ID):
close_position = uniswap.close_position(token_ID)

close_position(token_ID)
`

Expected behavior

If the function close_position fails to execute all 3 steps (Decrease liquidity, Collect and Burn) at a time, then upon calling it again it should finish the process. ("Burn" in my case, because "Decrease liquidity" and "Collect" work fine)

Additional context

[carlos-pansela]

Is anybody able to help please ?

[ErikBjare]

The error is triggered by the following line:

https://github.com/Uniswap/v3-periphery/blob/6cce88e63e176af1ddb6cc56e029110289622317/contracts/NonfungiblePositionManager.sol#L379

Looks like the position hasn't been cleared completely, which is a requirement to burn the LP token.

I'm unfortunately not familiar enough about the liquidity provision part of the code to say exactly what the issue is.

[ErikBjare]

I notice there are several wait_for_transaction_receipt calls in the close_liquidity method, which will make the transactions end up in different blocks.

It's possible that doing a multicall or sending them off at the same time (for inclusion into the same block) can address the issue. Just speculating though, not sure why positions aren't cleared entirely before burning.