feat: state.{Get,Set}Extra[SA any](*StateDB,types.ExtraPayloads,...) (

#48) * feat: `state.{Get,Set}Extra[SA any](*StateDB,types.ExtraPayloads,...)` * test: `GetExtra()` at each point in `CreateAccount()` + `SetExtra()` lifecycle * test: reverting extras to snapshot * test: `GetExtra()` after `StateDB.Copy()` and writes to original
ava-labs · Oct 9, 2024 · 77c5571 · 77c5571
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diff --git a/core/state/state.libevm.go b/core/state/state.libevm.go
@@ -0,0 +1,64 @@
+// Copyright 2024 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 state
+
+import (
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+// GetExtra returns the extra payload from the [types.StateAccount] associated
+// with the address, or a zero-value `SA` if not found. The
+// [types.ExtraPayloads] MUST be sourced from [types.RegisterExtras].
+func GetExtra[SA any](s *StateDB, p types.ExtraPayloads[SA], addr common.Address) SA {
+	stateObject := s.getStateObject(addr)
+	if stateObject != nil {
+		return p.FromStateAccount(&stateObject.data)
+	}
+	var zero SA
+	return zero
+}
+
+// SetExtra sets the extra payload for the address. See [GetExtra] for details.
+func SetExtra[SA any](s *StateDB, p types.ExtraPayloads[SA], addr common.Address, extra SA) {
+	stateObject := s.getOrNewStateObject(addr)
+	if stateObject != nil {
+		setExtraOnObject(stateObject, p, addr, extra)
+	}
+}
+
+func setExtraOnObject[SA any](s *stateObject, p types.ExtraPayloads[SA], addr common.Address, extra SA) {
+	s.db.journal.append(extraChange[SA]{
+		payloads: p,
+		account:  &addr,
+		prev:     p.FromStateAccount(&s.data),
+	})
+	p.SetOnStateAccount(&s.data, extra)
+}
+
+// extraChange is a [journalEntry] for [SetExtra] / [setExtraOnObject].
+type extraChange[SA any] struct {
+	payloads types.ExtraPayloads[SA]
+	account  *common.Address
+	prev     SA
+}
+
+func (e extraChange[SA]) dirtied() *common.Address { return e.account }
+
+func (e extraChange[SA]) revert(s *StateDB) {
+	e.payloads.SetOnStateAccount(&s.getStateObject(*e.account).data, e.prev)
+}
diff --git a/core/state/state.libevm_test.go b/core/state/state.libevm_test.go
@@ -0,0 +1,172 @@
+// Copyright 2024 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 state_test
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/state/snapshot"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+	"github.com/ethereum/go-ethereum/libevm/ethtest"
+	"github.com/ethereum/go-ethereum/triedb"
+)
+
+func TestGetSetExtra(t *testing.T) {
+	type accountExtra struct {
+		// Data is a pointer to test deep copying.
+		Data *[]byte // MUST be exported; I spent 20 minutes investigating failing tests because I'm an idiot
+	}
+
+	types.TestOnlyClearRegisteredExtras()
+	t.Cleanup(types.TestOnlyClearRegisteredExtras)
+	// Just as its Data field is a pointer, the registered type is a pointer to
+	// test deep copying.
+	payloads := types.RegisterExtras[*accountExtra]()
+
+	rng := ethtest.NewPseudoRand(42)
+	addr := rng.Address()
+	nonce := rng.Uint64()
+	balance := rng.Uint256()
+	buf := rng.Bytes(8)
+	extra := &accountExtra{Data: &buf}
+
+	views := newWithSnaps(t)
+	stateDB := views.newStateDB(t, types.EmptyRootHash)
+
+	assert.Nilf(t, state.GetExtra(stateDB, payloads, addr), "state.GetExtra() returns zero-value %T if before account creation", extra)
+	stateDB.CreateAccount(addr)
+	stateDB.SetNonce(addr, nonce)
+	stateDB.SetBalance(addr, balance)
+	assert.Nilf(t, state.GetExtra(stateDB, payloads, addr), "state.GetExtra() returns zero-value %T if after account creation but before SetExtra()", extra)
+	state.SetExtra(stateDB, payloads, addr, extra)
+	require.Equal(t, extra, state.GetExtra(stateDB, payloads, addr), "state.GetExtra() immediately after SetExtra()")
+
+	root, err := stateDB.Commit(1, false) // arbitrary block number
+	require.NoErrorf(t, err, "%T.Commit(1, false)", stateDB)
+	require.NotEqualf(t, types.EmptyRootHash, root, "root hash returned by %T.Commit() is not the empty root", stateDB)
+
+	t.Run(fmt.Sprintf("retrieve from %T", views.snaps), func(t *testing.T) {
+		iter, err := views.snaps.AccountIterator(root, common.Hash{})
+		require.NoErrorf(t, err, "%T.AccountIterator(...)", views.snaps)
+		defer iter.Release()
+
+		require.Truef(t, iter.Next(), "%T.Next() (i.e. at least one account)", iter)
+		require.NoErrorf(t, iter.Error(), "%T.Error()", iter)
+
+		t.Run("types.FullAccount()", func(t *testing.T) {
+			got, err := types.FullAccount(iter.Account())
+			require.NoErrorf(t, err, "types.FullAccount(%T.Account())", iter)
+
+			want := &types.StateAccount{
+				Nonce:    nonce,
+				Balance:  balance,
+				Root:     types.EmptyRootHash,
+				CodeHash: types.EmptyCodeHash[:],
+			}
+			payloads.SetOnStateAccount(want, extra)
+
+			if diff := cmp.Diff(want, got); diff != "" {
+				t.Errorf("types.FullAccount(%T.Account()) diff (-want +got):\n%s", iter, diff)
+			}
+		})
+
+		require.Falsef(t, iter.Next(), "%T.Next() after first account (i.e. only one)", iter)
+	})
+
+	t.Run(fmt.Sprintf("retrieve from new %T", stateDB), func(t *testing.T) {
+		s := views.newStateDB(t, root)
+		assert.Equalf(t, nonce, s.GetNonce(addr), "%T.GetNonce()", s)
+		assert.Equalf(t, balance, s.GetBalance(addr), "%T.GetBalance()", s)
+		assert.Equal(t, extra, state.GetExtra(s, payloads, addr), "state.GetExtra()")
+	})
+
+	t.Run("reverting to snapshot", func(t *testing.T) {
+		s := views.newStateDB(t, root)
+		snap := s.Snapshot()
+
+		oldExtra := extra
+		buf := append(*oldExtra.Data, rng.Bytes(8)...)
+		newExtra := &accountExtra{Data: &buf}
+
+		state.SetExtra(s, payloads, addr, newExtra)
+		assert.Equalf(t, newExtra, state.GetExtra(s, payloads, addr), "state.GetExtra() after overwriting with new value")
+		s.RevertToSnapshot(snap)
+		assert.Equalf(t, oldExtra, state.GetExtra(s, payloads, addr), "state.GetExtra() after reverting to snapshot")
+	})
+
+	t.Run(fmt.Sprintf("%T.Copy()", stateDB), func(t *testing.T) {
+		require.Equalf(t, reflect.Pointer, reflect.TypeOf(extra).Kind(), "extra-payload type")
+		require.Equalf(t, reflect.Pointer, reflect.TypeOf(extra.Data).Kind(), "extra-payload field")
+
+		orig := views.newStateDB(t, root)
+		cp := orig.Copy()
+
+		oldExtra := extra
+		buf := append(*oldExtra.Data, rng.Bytes(8)...)
+		newExtra := &accountExtra{Data: &buf}
+
+		assert.Equalf(t, oldExtra, state.GetExtra(orig, payloads, addr), "GetExtra([original %T]) before setting", orig)
+		assert.Equalf(t, oldExtra, state.GetExtra(cp, payloads, addr), "GetExtra([copy of %T]) returns the same payload", orig)
+		state.SetExtra(orig, payloads, addr, newExtra)
+		assert.Equalf(t, newExtra, state.GetExtra(orig, payloads, addr), "GetExtra([original %T]) returns overwritten payload", orig)
+		assert.Equalf(t, oldExtra, state.GetExtra(cp, payloads, addr), "GetExtra([copy of %T]) returns original payload despite overwriting on original", orig)
+	})
+}
+
+// stateViews are different ways to access the same data.
+type stateViews struct {
+	snaps    *snapshot.Tree
+	database state.Database
+}
+
+func (v stateViews) newStateDB(t *testing.T, root common.Hash) *state.StateDB {
+	t.Helper()
+	s, err := state.New(root, v.database, v.snaps)
+	require.NoError(t, err, "state.New()")
+	return s
+}
+
+func newWithSnaps(t *testing.T) stateViews {
+	t.Helper()
+	empty := types.EmptyRootHash
+	kvStore := memorydb.New()
+	ethDB := rawdb.NewDatabase(kvStore)
+	snaps, err := snapshot.New(
+		snapshot.Config{
+			CacheSize: 16, // Mb (arbitrary but non-zero)
+		},
+		kvStore,
+		triedb.NewDatabase(ethDB, nil),
+		empty,
+	)
+	require.NoError(t, err, "snapshot.New()")
+
+	return stateViews{
+		snaps:    snaps,
+		database: state.NewDatabase(ethDB),
+	}
+}