From 3b2d6c87ebd66d1491e387bda57ca6b5052bc1e7 Mon Sep 17 00:00:00 2001
From: Guillaume Ballet <3272758+gballet@users.noreply.github.com>
Date: Thu, 16 Oct 2025 15:59:14 +0200
Subject: [PATCH] add handling for the TransitionTree after rebase

---
 core/state/database.go     | 2 ++
 core/state/state_object.go | 4 ++++
 trie/transition.go         | 3 ++-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/core/state/database.go b/core/state/database.go
index 3a0ac422ee..58d0ccfe82 100644
--- a/core/state/database.go
+++ b/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))
 	}
diff --git a/core/state/state_object.go b/core/state/state_object.go
index cde5d11bba..fdeb4254c1 100644
--- a/core/state/state_object.go
+++ b/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:
diff --git a/trie/transition.go b/trie/transition.go
index da49c6cdc2..c6eecd3937 100644
--- a/trie/transition.go
+++ b/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,
 	}
 }