core/state: state copy bugfixes with Verkle Trees (#31696)

This change addresses critical issues in the state object duplication
process specific to Verkle trie implementations. Without these
modifications, updates to state objects fail to propagate correctly
through the trie structure after a statedb copy operation, leading to
inaccuracies in the computation of the state root hash.

---------

Co-authored-by: Guillaume Ballet <3272758+gballet@users.noreply.github.com>

core/state/database.go

@@ -302,6 +302,8 @@ func mustCopyTrie(t Trie) Trie {
 		return t.Copy()
 	case *trie.VerkleTrie:
 		return t.Copy()
+	case *trie.TransitionTrie:
+		return t.Copy()
 	default:
 		panic(fmt.Errorf("unknown trie type %T", t))
 	}

core/state/state_object.go

@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
 	"github.com/ethereum/go-ethereum/trie/trienode"
 	"github.com/holiman/uint256"
 )
@@ -494,8 +495,20 @@ func (s *stateObject) deepCopy(db *StateDB) *stateObject {
 		selfDestructed:     s.selfDestructed,
 		newContract:        s.newContract,
 	}
-	if s.trie != nil {
+
+	switch s.trie.(type) {
+	case *trie.VerkleTrie:
+		// Verkle uses only one tree, and the copy has already been
+		// made in mustCopyTrie.
+		obj.trie = db.trie
+	case *trie.TransitionTrie:
+		// Same thing for the transition tree, since the MPT is
+		// read-only.
+		obj.trie = db.trie
+	case *trie.StateTrie:
 		obj.trie = mustCopyTrie(s.trie)
+	case nil:
+		// do nothing
 	}
 	return obj
 }

trie/transition.go

@@ -211,7 +211,8 @@ func (t *TransitionTrie) UpdateStem(key []byte, values [][]byte) error {
 func (t *TransitionTrie) Copy() *TransitionTrie {
 	return &TransitionTrie{
 		overlay: t.overlay.Copy(),
-		base:    t.base.Copy(),
+		// base in immutable, so there is no need to copy it
+		base:    t.base,
 		storage: t.storage,
 	}
 }