From 9ae4f0e80c4e6c03370d1e9da6097b141ac7ff33 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Sun, 22 Jan 2023 01:41:52 +0100
Subject: [PATCH] Copy original state of wizard to avoid side effect

Closes #4948
---
 trytond/trytond/wizard/wizard.py | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/trytond/trytond/wizard/wizard.py b/trytond/trytond/wizard/wizard.py
index cf82f89a6e..457d3ae7e2 100644
--- a/trytond/trytond/wizard/wizard.py
+++ b/trytond/trytond/wizard/wizard.py
@@ -214,8 +214,18 @@ class Wizard(URLMixin, PoolBase):
 
         # Copy states
         for attr in dir(cls):
-            if isinstance(getattr(cls, attr), State):
-                setattr(cls, attr, copy.deepcopy(getattr(cls, attr)))
+            if not isinstance(getattr(cls, attr), State):
+                continue
+            state_name = attr
+            state = getattr(cls, state_name)
+            # Copy the original state definition to prevent side-effect with
+            # the mutable attributes
+            for parent_cls in cls.__mro__:
+                parent_state = getattr(parent_cls, state_name, None)
+                if isinstance(parent_state, State):
+                    state = parent_state
+            state = copy.deepcopy(state)
+            setattr(cls, attr, state)
 
     @classmethod
     def __post_setup__(cls):