Proxy & Mutisig did not respect PostDispatchInfo to disable fee

[xlc]

With #6749, it is possible to mark a success transaction execution to be free.
However this is not respected by proxy and multisig.

I think we will want to make proxy/multisig call free if the underlying tx call is free?

cc @shawntabrizi

[shawntabrizi]

Thanks, I will look into it 👍

[xlc]

Batch is bit complicated, we may want a partial refund?

[xlc]

Too bad Acala Foundation on Kusama / Polkadot cannot enjoy #7661 because our account is multisig / proxy.

[emielsebastiaan]

Same for Polkascan Foundation's multisig account on Kusama. 😃

[stale]

Hey, is anyone still working on this? Due to the inactivity this issue has been automatically marked as stale. It will be closed if no further activity occurs. Thank you for your contributions.

[TorstenStueber]

This feature would actually be quite important when using multisig for the sudo account. A single runtime upgrade executed through the sudo account using pallet-multisig could cost about 5-20 units of native tokens (considering a typical parachain configuration).

This number originates from the dominating term of the formula for transaction fees. This term is LengthToFee applied to the length of the extrinsic. Most (Polkadot) parachains define LengthToFee to just be the multiplier 1 unit/100_000. The length of an extrinsic for a runtime upgrade is about the size of the runtime and that is around 1MByte.