There should be a warning if we know that a Safe tx will fail

[rmeissner]

What is this feature about? (1 sentence)

This will display a warning in case the Safe knows that a tx will (most likely) fail.

Why is it needed? What is the value? For whom do we build it?

• If we know already, that a tx will fail, then we could save users gas costs.
• When executing transactions via MetaMask that will revert, MetaMask warns you before you execute the transaction. An easy example is trying to transfer more ERC20 tokens than the account holds to someone else.
• Because of implementation details the execution transaction for a Safe transaction will not fail, therefore MetaMask cannot warn you.

High-level overview of the feature

• Please check before submitting the execution transaction to the wallet if execTransactionreturns true.
• In case there will be an error, display that to the user. Something like "This transaction will most likely fail."
• Note 1: This is only possible for the executor, i.e. when all signatures are present.
• Note 2: It should still be possible for the user to submit the tx. There are cases, where estimation is not possible
• Note 3: Please don't implement the new signing flow design as part of this ticket. That should be done separate.

Misc

This is how Metamask displays this:

Updates

• Sep 30, Tobi: Add more context to this.

[pablofullana]


https://github.com/gnosis/safe-react/blob/development/src/routes/safe/components/Balances/SendModal/screens/ReviewTx/index.tsx#L54


[pablofullana]

Let's work an initial fix w/o too much design focus. Iterate later.

[posthnikova]

Confirm with execute popup:

Execute popup:

If the goal of this warning is to save gas costs then it will work better in the future when we have proper rejections (with options to either replace tx with empty tx or useful tx).

The options for the user when they see this warning are:
1 - Proceed with execution, pay gas, transaction fails
2 - Proceed with execution, pay gas, transaction is successful
3 - Collect rejections and cancel, pay gas for executing cancellation
4 - Do nothing, transaction stays in the queue - in this case it blocks other transactions
Right now the best option is cancelling, the user still pays gas but it should be cheaper.