Anvil's debug_traceTransaction behaviour differs from geth

[shekhirin]

Component

Anvil

Describe the bug

As of 6e5a613, Anvil's debug_traceTransaction differs from geth in several places which are also on screenshots:

1. Incorrect memory state during MSTORE It was fixed for Geth in ethereum/go-ethereum@97f308a but my RPC uses Erigon which doesn't have these changes and still does memory expansion before tracing: https://github.com/ledgerwatch/erigon/blob/cd8cad6a8908970fa092aa5e2dcd8f38aedccd89/core/vm/interpreter.go#L316-L323
2. Remaining gas and instruction gas cost calculated incorrectly:

   foundry/evm/src/executor/inspector/tracer.rs

   Lines 138 to 139 in 6e5a613

   	// TODO: calculate spent gas as in `Debugger::step`
   	step.gas_cost = step.gas - interp.gas.remaining();

[gakonst]

Good catch. Yep we want this to be 1:1 compatible. cc @mattsse to keep this in mind for reth, we want byte compatibility I think with Geth RPC (esp. for debug_traceTransaction) and with Parity's tracing responses