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Fails when swapping USDT=>WBNB #363
Description
I was trying to swap from USDT => BNB but had incorrectly set the address of BNB to WBNB address by mistake. I came across an error from pancake swap saying IDENTICAL ADDRESSES and after stepping through the call stack I could see when its building the txn the second element is the same as the last 3rd element in the routing list. This doesn't cause problems when swapping from USDT to native BNB, but it does cause problems when swapping USDT => WBNB.
Is there a reason weth have to be in the routing chain? Can't it just be a chain input/output?
#v2 uniswap being used here
elif self.version == 2:
min_tokens_bought = int(
(1 - slippage)
* self._get_token_token_input_price(
input_token, output_token, qty, fee=fee
)
)
if fee_on_transfer:
func = (
self.router.functions.swapExactTokensForTokensSupportingFeeOnTransferTokens
)
else:
func = self.router.functions.swapExactTokensForTokens
return self._build_and_send_tx(
func(
qty,
min_tokens_bought,
[input_token, self.get_weth_address(), output_token],
recipient,
self._deadline(),
),
)Full function
def _token_to_token_swap_input(
self,
input_token: AddressLike,
output_token: AddressLike,
qty: int,
recipient: Optional[AddressLike],
fee: int,
slippage: float,
fee_on_transfer: bool = False,
) -> HexBytes:
"""Convert tokens to tokens given an input amount."""
# Balance check
input_balance = self.get_token_balance(input_token)
if qty > input_balance:
raise InsufficientBalance(input_balance, qty)
if recipient is None:
recipient = self.address
if input_token == ETH_ADDRESS:
raise ValueError
elif output_token == ETH_ADDRESS:
raise ValueError
if self.version == 1:
token_funcs = self._exchange_contract(input_token).functions
# TODO: This might not be correct
min_tokens_bought, min_eth_bought = self._calculate_max_output_token(
input_token, qty, output_token
)
func_params = [
qty,
min_tokens_bought,
min_eth_bought,
self._deadline(),
output_token,
]
if not recipient:
function = token_funcs.tokenToTokenSwapInput(*func_params)
else:
func_params.insert(len(func_params) - 1, recipient)
function = token_funcs.tokenToTokenTransferInput(*func_params)
return self._build_and_send_tx(function)
elif self.version == 2:
min_tokens_bought = int(
(1 - slippage)
* self._get_token_token_input_price(
input_token, output_token, qty, fee=fee
)
)
if fee_on_transfer:
func = (
self.router.functions.swapExactTokensForTokensSupportingFeeOnTransferTokens
)
else:
func = self.router.functions.swapExactTokensForTokens
return self._build_and_send_tx(
func(
qty,
min_tokens_bought,
[input_token, self.get_weth_address(), output_token],
recipient,
self._deadline(),
),
)
elif self.version == 3:
if fee_on_transfer:
raise Exception("fee on transfer not supported by Uniswap v3")
min_tokens_bought = int(
(1 - slippage)
* self._get_token_token_input_price(
input_token, output_token, qty, fee=fee
)
)
sqrtPriceLimitX96 = 0
return self._build_and_send_tx(
self.router.functions.exactInputSingle(
{
"tokenIn": input_token,
"tokenOut": output_token,
"fee": fee,
"recipient": recipient,
"deadline": self._deadline(),
"amountIn": qty,
"amountOutMinimum": min_tokens_bought,
"sqrtPriceLimitX96": sqrtPriceLimitX96,
}
),
self._get_tx_params(),
)
else:
raise ValueError # pragma: no cover
Activity
kancom commentedon Jan 27, 2024
same thing for Etherium's Uniswap. Majory of new pairs are WETH quoted with..
fix: also avoid duplicate WETH in _token_to_token_swap_output (closes u…
fix: avoid duplicate WETH in swap path when input/output is WETH (closes