go-ethereum/core/vm/interface.libevm.go
Arran Schlosberg 9021836d7d
feat: vm.Hooks.PreprocessingGasCharge() (#235)
## Why this should be merged

In lieu of modifications to `core.IntrinsicGas()`, required for support
of Warp in SAE.

If we were to introduce variadic `options.Option`s to `IntrinsicGas()`,
it's impossible to guarantee that they would always be passed. The
`types.Transaction` itself isn't actually passed to `IntrinsicGas()`
either, so we can't rely on it to carry payloads/hooks.

## How this works

`vm.Hooks` are extended to include `PreprocessingGasCharge(tx
common.Hash) (uint64, error)`, which returns the amount of gas to be
charged between `core.IntrinsicGas` and `vm.EVM` execution charges. The
two entry points to execution, `vm.EVM.Call()` and `vm.EVM.Create()` are
modified to first spend said charge before running upstream logic.

The new hook is defined on a separate interface definition, embedded in
`vm.Hooks`, to allow types to implement just that method and enforce it
with the `var _ vm.Preprocessor = (*impl)(nil)` pattern.

## How this was tested

Integration tests via both `core.ApplyTransaction()` and
`core.ApplyMessage()`. The former is more comprehensive, while the
latter allows for inspection of interim error values.

---------

Signed-off-by: Arran Schlosberg <519948+ARR4N@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Austin Larson <78000745+alarso16@users.noreply.github.com>
2025-12-15 20:49:13 +00:00

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// Copyright 2025 the libevm authors.
//
// The libevm additions to go-ethereum are free software: you can redistribute
// them and/or modify them under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The libevm additions are distributed in the hope that they will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see
// <http://www.gnu.org/licenses/>.
package vm
import "github.com/ava-labs/libevm/common"
// StateDBRemainder defines methods not included in the geth definition of
// [StateDB] but present on the concrete type and exposed for libevm
// functionality.
type StateDBRemainder interface {
TxHash() common.Hash
TxIndex() int
}