Simulated backend Rollback() function should set gas tip back to the parameter passed by config

[dahu33]

System information

Geth version: 1.14.8
OS & Version: OSX

Expected behaviour

Calling the Rollback() function on the simulated backend should set gas tip back to parameter passed by config as it was the case before #28202 was merged.

Actual behaviour

Currently the gas tip is arbitrary set to 1 Gwei after calling the Rollback() function, which is not even the default config parameter (1 wei).

There is a TODO in the code left by @MariusVanDerWijden here:

go-ethereum/eth/catalyst/simulated_beacon.go

Lines 276 to 277 in a9523b6

	// TODO (Marius van der Wijden): set gas tip to parameter passed by config
	c.eth.TxPool().SetGasTip(big.NewInt(params.GWei))

Steps to reproduce the behaviour

1. Create a new simulated client with the default values.
2. Call Rollback()
3. Make a TX using the suggested gas tip.

You will get the error transaction underpriced: gas tip cap 1000000, minimum needed 1000000000.

[rjl493456442]

Would you like to submit the pull request to fix it?

[dahu33]

Would you like to submit the pull request to fix it?

Would love to but might need a bit of guidance on what would be the preferred strategy. I see two solutions so far:

1. saving the gas tip value inside the TxPool struct and exposing a getter func (p *TxPool) GetGasTip() *big.Int
2. saving the initial gas tip value inside the SimulatedBeacon struct