Implement __deepcopy__ on ImmutableDict

Closes #13408

trytond/trytond/tests/test_tools.py

@@ -7,6 +7,7 @@ import doctest
 import email.message
 import sys
 import unittest
+from copy import deepcopy
 from io import BytesIO
 from unittest.mock import patch
 
@@ -585,6 +586,17 @@ class ImmutableDictTestCase(TestCase):
         with self.assertRaises(TypeError):
             d.update({'foo': 'bar'})
 
+    def test_deepcopy(self):
+        "deepcopying should be possible"
+        original = ImmutableDict(foo={'a': 1}, bar=2, baz=1.3)
+        copy = deepcopy(original)
+
+        self.assertEqual(original, copy)
+        self.assertIsNot(original, copy)
+
+        self.assertEqual(original['foo'], copy['foo'])
+        self.assertIsNot(original['foo'], copy['foo'])
+
 
 class DomainInversionTestCase(TestCase):
     "Test domain_inversion"

trytond/trytond/tools/immutabledict.py

@@ -1,5 +1,7 @@
 # This file is part of Tryton.  The COPYRIGHT file at the toplevel of this
 # repository contains the full copyright notices and license terms.
+from copy import deepcopy
+
 
 class ImmutableDict(dict):
 
@@ -8,6 +10,10 @@ class ImmutableDict(dict):
     def _not_allowed(cls, *args, **kwargs):
         raise TypeError("Operation not allowed on ImmutableDict")
 
+    def __deepcopy__(self, memo):
+        return ImmutableDict(
+            (k, deepcopy(v, memo=memo)) for k, v in self.items())
+
     __setitem__ = _not_allowed
     __delitem__ = _not_allowed
     __ior__ = _not_allowed