When signing a transaction Phantom assumes it's the sender too

[mikestead]

First a thanks for the great work you've done on Phantom, it makes all our lives in this ecosystem a lot better.

In your docs you state that signAndSendTransaction, signTransaction , signAllTransactions make the default assumption you are good to apply Priority Fees and be the fee payer.

In multisig this will often not be the case, and if we go the way of Account Abstraction this will be the norm.

One common example is a Paymaster service sponsoring transactions.

In your docs you mention if another signer gets in first it will prevent this logic.

Unfortunately that brings with it a bunch of problems that are unnecessary (e.g. no longer managing final validation, submission and guaranteed state management either side of the tx). Bottom line, it almost always makes sense for the fee payer/submitter to sign last.

My feedback/request is that these operations should be standard across wallets and avoid surprises. There should be little deviation otherwise developers have to build to each wallet provider.

I can see the case where signAndSendTransaction is making the explicit request for a wallet to manage the send so priority fees are in your domain, but signTransaction makes no such case. It would be great if all wallets left that one to only sign and not manipulate the TX in any other way.

[mikestead]

I wonder if a simple solution to this might be to check transaction.feePayer and if it's not the pubkey under Phantom's control to avoid any fee management logic.

[mikestead]

I'm going to close this off and just apply my own priority fees which I hope should fix this. My suggestion above RE feePayer still seems like a good idea, although backwards compatibility may be a bigger worry for you now.