Set maxFeePerGas to gasCap

[fleupold]

Description

Our gas estimation logic was written prior to EIP1559 which changed Ethereum's transaction fee mechanism from a "pay as bid" to a "truthful bidding" mechanism. Before, users would need to think

1. How much they are maximally willing to pay for their transaction (1000 gwei by default for us)
2. How much they should bid for transaction inclusion (dependent on current demand/supply)

They would always get charged 2.

Now, people only have to answer 1. and can rely on Ethereum's elastic base fee to make sure they are only getting charged as much as needed (the current base fee).

Priority fees remain a "pay as bid" part of the pricing, however those values tend to be very small (1-3 gwei) compared to the base fee (20-500 gwei).

This PR start to bid truthfully with regards to the maximum fee we are willing to pay. This simplifies a bunch of the solution submission logic as we now longer have to predict the maximum base fee in the future.

Changes

• Always set maxFeePerGas to gas_price_cap

How to test

Run e2e test, see settlements are now submitted with very high cap.

Related Issues

Fixes #1874

[sunce86]

Are we gonna cleanup MAX_FEE_FACTOR in a follow up PR?

[sunce86]

gas_price_cap should be probably updated to U256, not related to this PR

[fleupold]

#2301

[fleupold]

Are we gonna cleanup MAX_FEE_FACTOR in a follow up PR?

It's being remove as part of #2294

[MartinquaXD]

Either the comment is wrong or you should be using .min(), no?

Suggested change

	// Use the lowest max_fee_per_gas of all mempools as the max_fee_per_gas
	// Use the highest max_fee_per_gas of all mempools as the max_fee_per_gas

[fleupold]

Turns out that this PR isn't having the desired effect yet, since we are overriding our maxFeePerGas value in the legacy submission with a fresh estimate (we only reuse the previously computed maxFeePerGas as a cap in that case).

services/crates/solver/src/settlement_submission/submitter.rs

Lines 155 to 171 in 6b4a053

	async fn estimate_with_limits(
	&self,
	gas_limit: f64,
	time_limit: Duration,
	) -> Result<GasPrice1559> {
	let mut estimate = self
	.inner
	.estimate_with_limits(gas_limit, time_limit)
	.await?;
	let additional_tip = self.max_additional_tip.min(
	estimate.max_fee_per_gas.min(self.max_fee_per_gas)
	* self.additional_tip_percentage_of_max_fee,
	);
	estimate.max_fee_per_gas =
	(estimate.max_fee_per_gas + additional_tip).min(self.max_fee_per_gas);

Will change once we move to native solution submission