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Metamask: Uniswap Web3 Py token purchase fails with execution returned

As a Web3 developer, you are probably no stranger to the complexities of trading and interacting with decentralized exchanges (DEXs) like Uniswap. However, I have come across a frustrating issue that is making it difficult for me to successfully execute my trades.

My issue lies in attempting to purchase tokens on Uniswap V2 using the swapExactETHForTokens function from the Web3 Python library (w3). Specifically, every time I try to execute this method, it fails with an execution error message returned. This is causing significant inconvenience and delays in my trading flow.

Problem: Execution return error

To understand what’s going on, let me break down the code snippet that triggers the problem:

from web3 import Web3
w3 = Web3(Web3.HTTPProvider('
def swap_exact_eth_for_tokens(uniswap_address, token_to_swap, amount):
return w3.eth.swapExactETHForTokens(
uniswap_address,
token_to_swap,
[amount],
{"from": '0xYourAccountAddress', "gasPrice": 20},
{"gas": 1000000, "maxPriorityFeeGwei": 10}
)

Usage:
token_to_swap = w3.eth.coinbase
amount = w3.toWei("1", 'ether')
try:
result = swap_exact_eth_for_tokens(token_to_swap, token_to_swap, amount)
print(result)
except exception as e:
print(e)

Here’s what happens when I run this code:

• The swapExactETHForTokens function is called with the Uniswap address, the token to swap, and the amount.

• The function attempts to execute the trade using the specified parameters (from: “0xYourAccountAddress”).

• However, due to some internal issue in the Metamask library, the swapExactETHForTokens function executes with a null error message.

Mitigation

To resolve this issue, I have tried several possible solutions:

• Check for gas issues: One possible cause of the execution aborted error could be a mismatch in gas limits between the gas supplied to Metamask and the actual gas consumption during the trade.

• Increase swap parameters: Another option is to increase the parameters passed to swapExactETHForTokens, such as increasing the amount or adding more uniswap addresses to the swap.

Troubleshooting

Unfortunately, after trying various solutions, I was unable to resolve the issue with these methods. It seems that the underlying issue lies with the Metamask library itself, which is not functioning properly during my trade attempts.

To resolve this issue, I recommend that you take the following steps:

• Check for library updates:

  Make sure you are using the latest version of the Web3 Python library to ensure compatibility.

• Contact Support or Search Online Forums: Contact the Metamask Support Team or online forums for help with your specific problem.

Although this issue is frustrating, I hope that by sharing your experience, others will be able to find a solution and solve their own problems executing trades on Uniswap V2 using the swapExactETHForTokens function.

Conclusion

The Metamask library appears to have an internal bug that causes problems with executing certain store functions. To solve this problem, I recommend checking the gas limit mismatch or increasing the swap parameters, but unfortunately, these methods did not work for me in my case.