From ef8d6eda013ee677e3ecfbc73afdf15ea2739469 Mon Sep 17 00:00:00 2001
From: Raphael Collet <rco@openerp.com>
Date: Fri, 15 Jan 2016 13:46:14 +0100
Subject: [PATCH] [IMP] fields: overriding a field with `default=None` discards
 its default value

---
 openerp/addons/test_inherit/models.py             | 5 +++--
 openerp/addons/test_inherit/tests/test_inherit.py | 6 ++++++
 openerp/fields.py                                 | 5 +++--
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/openerp/addons/test_inherit/models.py b/openerp/addons/test_inherit/models.py
index 0875c4fed5a..241bca11a02 100644
--- a/openerp/addons/test_inherit/models.py
+++ b/openerp/addons/test_inherit/models.py
@@ -12,6 +12,7 @@ class mother(models.Model):
     }
     _defaults = {
         'name': 'Foo',
+        'state': 'a',
     }
 
     surname = fields.Char(compute='_compute_surname')
@@ -43,8 +44,8 @@ class mother(models.Model):
     # extend the name field: make it required and change its default value
     name = fields.Char(required=True, default='Bar')
 
-    # extend the selection of the state field
-    state = fields.Selection(selection_add=[('c', 'C')])
+    # extend the selection of the state field, and discard its default value
+    state = fields.Selection(selection_add=[('c', 'C')], default=None)
 
     # override the computed field, and extend its dependencies
     @api.one
diff --git a/openerp/addons/test_inherit/tests/test_inherit.py b/openerp/addons/test_inherit/tests/test_inherit.py
index ddf5d1424a0..2bfd2715dc3 100644
--- a/openerp/addons/test_inherit/tests/test_inherit.py
+++ b/openerp/addons/test_inherit/tests/test_inherit.py
@@ -40,6 +40,12 @@ class test_inherits(common.TransactionCase):
         self.assertEqual(daughter._defaults.get('name'), "Baz")
         self.assertEqual(daughter.default_get(['name']), {'name': "Baz"})
 
+        # the field mother.state must have no default value
+        field = mother._fields['state']
+        self.assertFalse(field.default)
+        self.assertNotIn('state', mother._defaults)
+        self.assertEqual(mother.default_get(['state']), {})
+
         # the field daughter.template_id should have
         # comodel_name='test.inherit.mother', string='Template', required=True
         field = daughter._fields['template_id']
diff --git a/openerp/fields.py b/openerp/fields.py
index d9943f98f65..960134ba082 100644
--- a/openerp/fields.py
+++ b/openerp/fields.py
@@ -454,8 +454,9 @@ class Field(object):
                 if 'default' in field.args:
                     # take the value, and adapt it for model._defaults
                     value = field.args['default']
-                    self.default = default_new_to_new(self, value)
-                    model._defaults[name] = default_new_to_old(self, value)
+                    if value is not None:
+                        self.default = default_new_to_new(self, value)
+                        model._defaults[name] = default_new_to_old(self, value)
                     return
 
             defaults = klass.__dict__.get('_defaults') or {}