This PR includes the following 2 improvements:
## Ethereum Client
Author: @yrong
### Original Upstream PRs
- https://github.com/Snowfork/polkadot-sdk/pull/123
- https://github.com/Snowfork/polkadot-sdk/pull/125
### Description
The Ethereum client syncs beacon headers as they are finalized, and
imports every execution header. When a message is received, it is
verified against the import execution header. This is unnecessary, since
the execution header can be sent with the message as proof. The recent
Deneb Ethereum upgrade made it easier to locate the relevant beacon
header from an execution header, and so this improvement was made
possible. This resolves a concern @svyatonik had in our initial Rococo
PR:
https://github.com/paritytech/polkadot-sdk/pull/2522#discussion_r1431270691
## Inbound Queue
Author: @yrong
### Original Upstream PR
- https://github.com/Snowfork/polkadot-sdk/pull/118
### Description
When the AH sovereign account (who pays relayer rewards) is depleted,
the inbound message will not fail. The relayer just will not receive
rewards.
Both these changes were done by @yrong, many thanks. ❤️
---------
Co-authored-by: claravanstaden <Cats 4 life!>
Co-authored-by: Ron <yrong1997@gmail.com>
Co-authored-by: Vincent Geddes <vincent@snowfork.com>
Co-authored-by: Svyatoslav Nikolsky <svyatonik@gmail.com>
Bridging fees are calculated using a static ETH/DOT exchange rate that
can deviate significantly from the real-world exchange rate. We
therefore need to add a safety margin to the fee so that users almost
aways cover the cost of relaying.
# FAQ
> Why introduce a `multiplier` parameter instead of configuring an
exchange rate which already has a safety factor applied?
When converting from ETH to DOT, we need to _divide_ the multiplier by
the exchange rate, and to convert from DOT to ETH we need to _multiply_
the multiplier by the exchange rate.
> Other input parameters to the fee calculation can also deviate from
real-world values. These include substrate weights, gas prices, and so
on. Why does the multiplier introduced here not adjust those?
A single scalar multiplier won't be able to accommodate the different
volatilities efficiently. For example, gas prices are much more volatile
than exchange rates, and substrate weights hardly ever change.
So the pricing config relating to weights and gas prices should already
have some appropriate safety margin pre-applied.
# Detailed Changes:
* Added `multiplier` field to `PricingParameters`
* Outbound-queue fee is multiplied by `multiplier`
* This `multiplier` is synced to the Ethereum side
* Improved Runtime API for calculating outbound-queue fees. This API
makes it much easier to for configure parts of the system in preparation
for launch.
* Improve and clarify code documentation
Upstreamed from https://github.com/Snowfork/polkadot-sdk/pull/127
---------
Co-authored-by: Clara van Staden <claravanstaden64@gmail.com>
Co-authored-by: Adrian Catangiu <adrian@parity.io>
Removes the `bridges/snowbridge/parachain` directory and moves
everything up to under `snowbridge` directly. We are cleaning up our
local dev env after merging our crates into the polkadot-sdk.
---------
Co-authored-by: claravanstaden <Cats 4 life!>
Clara van Staden