[FIX] fields: make `related_sudo` work for draft records (used by onchange)

Accessing a related field with `related_sudo=True` on a draft record should
effectively traverse the fields as the admin user.

This fixes #5121, #7138.

openerp/addons/test_new_api/tests/test_new_fields.py

@@ -4,9 +4,9 @@
 from datetime import date, datetime
 from collections import defaultdict
 
-from openerp.exceptions import AccessError
+from openerp.exceptions import AccessError, except_orm
 from openerp.tests import common
-from openerp.exceptions import except_orm
+from openerp.tools import mute_logger
 
 
 class TestNewFields(common.TransactionCase):
@@ -391,7 +391,31 @@ class TestNewFields(common.TransactionCase):
         self.assertEqual(message.name, "[%s] %s" % (discussion.name, ''))
         self.assertEqual(message.size, len(BODY))
 
-    def test_41_defaults(self):
+    @mute_logger('openerp.addons.base.ir.ir_model')
+    def test_41_new_related(self):
+        """ test the behavior of related fields on new records. """
+        discussion = self.env.ref('test_new_api.discussion_0')
+        access = self.env.ref('test_new_api.access_discussion')
+
+        # make discussions unreadable for demo user
+        access.write({'perm_read': False})
+
+        # create an environment for demo user
+        demo_env = self.env(user=self.env.ref('base.user_demo'))
+        self.assertEqual(demo_env.user.login, "demo")
+
+        # create a new message as demo user
+        values = {'discussion': discussion.id}
+        message = demo_env['test_new_api.message'].new(values)
+        self.assertEqual(message.discussion, discussion)
+
+        # read the related field discussion_name
+        self.assertEqual(message.discussion.env, demo_env)
+        self.assertEqual(message.discussion_name, discussion.name)
+        with self.assertRaises(AccessError):
+            message.discussion.name
+
+    def test_50_defaults(self):
         """ test default values. """
         fields = ['discussion', 'body', 'author', 'size']
         defaults = self.env['test_new_api.message'].default_get(fields)

openerp/fields.py

@@ -539,8 +539,9 @@ class Field(object):
         others = records.sudo() if self.related_sudo else records
         for record, other in zip(records, others):
             if not record.id:
-                # draft record, do not switch to another environment
-                other = record
+                # draft records: copy record's cache to other's cache first
+                for name, value in record._cache.iteritems():
+                    other[name] = value
             # traverse the intermediate fields; follow the first record at each step
             for name in self.related[:-1]:
                 other = other[name][:1]