[FIX] models: copy field with unique constrain

When a model contains a field translatable which has a unique
constrain, it is impossible to copy a record. Indeed, the unicity
constrain is always triggered, even if the model takes in charge the
overriding of the copy method to avoid duplication.

Introduced with commit ce7f31b0b0, with the goal to target only
XML/HTML translations. We apply this behavior in case of a callable
translate property, to target only the desired problematic use case.

opw-749481

odoo/addons/base/tests/test_base.py

@@ -526,3 +526,8 @@ class TestGroups(TransactionCase):
         # create a cycle and check
         a.implied_ids = d
         self.assertFalse(a._check_m2m_recursion('implied_ids'))
+
+    def test_res_group_copy(self):
+        a = self.env['res.groups'].with_context(lang='en_US').create({'name': 'A'})
+        b = a.copy()
+        self.assertFalse(a.name == b.name)

odoo/models.py

@@ -4363,7 +4363,7 @@ class BaseModel(object):
                 trans_name, source_id, target_id = get_trans(field, old, new)
                 domain = [('name', '=', trans_name), ('res_id', '=', source_id)]
                 new_val = new_wo_lang[name]
-                if old.env.lang:
+                if old.env.lang and callable(field.translate):
                     # the new value *without lang* must be the old value without lang
                     new_wo_lang[name] = old_wo_lang[name]
                 for vals in Translation.search_read(domain):
@@ -4372,6 +4372,7 @@ class BaseModel(object):
                     del vals['module']      # duplicated vals is not linked to any module
                     vals['res_id'] = target_id
                     if vals['lang'] == old.env.lang and field.translate is True:
+                        vals['source'] = old_wo_lang[name]
                         # the value should be the new value (given by copy())
                         vals['value'] = new_val
                     Translation.create(vals)