Forwarders: accessing chain of senders onchain

[izqui]

Now default forwarders log the sender of every forward, making it possible to reconstruct the chain of forwards in a call offchain.

We should come up with a way to access this chain onchain so apps can check it.

A way could be to append this data at the end of the calldata. This would require you to trust the entire chain of contracts that forwarded which is no bueno, but cant think of anything trustless.

[sohkai]

Just wondering—is there a strong use case for accessing the forwarding chain on-chain?

I have the impression that if your app needs to know the forwarding chain to respond to an event on-chain, you're doing something wrong. If it was properly forwarded it to you, you shouldn't care which path it took.

[izqui]

The case I was thinking when I created this issue is to access who is the real originator of a call. We are not doing it right now, but imagine a voting app in which you cannot vote directly, but through a forwarding action, the voting app would need to know who is voting.

I have another idea for why this would be important but it is a bit of an edge case, so not too relevant.