eth_callBundle implementation has a bug (wrongly validating maxFeePerGas using state's baseFee)

[zently]

Describe the bug

reth node's eth_callBundle's implementation has a bug.
It falsely raises 'RpcInvalidTransactionError::FeeCapTooLow' when transactions are valid.

Explanation

reth currently validates for the incoming transaction's baseFee using the following code

(1) fetch the block environment given by the state block number

(rpc/rpc/src/eth/bundle.rs)

let block_id: reth_rpc_types::BlockId = state_block_number.into();
let (cfg, mut block_env, at) = self.inner.eth_api.evm_env_at(block_id).await?;

(2) for each incoming transaction, it uses block's basefee to check whether tx has set sufficient gas fee.

But it is 'INCORRECT' in that, [target block]'s base fee could be lower than the [state block]s base fee.
If [state block]'s utilization rate is low, its next block will have lower base fee (london fork).
i.e. it should be calculated, rather than just copying the raw value of the state block.

(rpc/rpc/src/eth/bundle.rs)

let basefee = Some(block_env.basefee.to::<u64>());
let gas_price = tx
    .effective_tip_per_gas(basefee)
    .ok_or_else(|| RpcInvalidTransactionError::FeeCapTooLow)?;

Suggestion

below suggestion is how flashbots-mev-geth's implementation handles above situation.
link to original source

• update the 'EthCallBundle' type to include 'basefee' so user can override the target block's base fee
• calculate the base fee using the [state block]'s utilization rate (London Fork)

Steps to reproduce

Steps to reproduce:

(1) call eth_callBundle with the following transaction with the parameters

tx: 0x024edcc98eccbae9fb5ef859d101abafd50baa9ba668c79aa8333c4db173fa92
block_number: 20172628
state_block_number: 20172627

block (20172627)'s basefee is 2507760629
block (20172628)'s basefee is 2440794978

and reth uses state block's basefee to reject the tx simulation.

Node logs

No response

Platform(s)

Linux (x86)

What version/commit are you on?

1.0.0-rc.2

What database version are you on?

Current database version: 2

Which chain / network are you on?

mainnet (1)

What type of node are you running?

Full via --full flag

What prune config do you use, if any?

No response

If you've built Reth from source, provide the full command you used

No response

Code of Conduct

• I agree to follow the Code of Conduct

[mattsse]

thanks, this should indeed calc the next basefee,
will fix once we've added the missing fields