add handling for the TransitionTree after rebase

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

@@ -501,6 +501,10 @@ func (s *stateObject) deepCopy(db *StateDB) *stateObject {
 		// 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:

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,
 	}
 }