[FIX] models: default_get() shall not return a dict as a many2one value

When a new record is returned as the value for a many2one on a new record, the
method Many2one.convert_to_write() now returns a NewID, and default_get() then
discards that value from its result. This makes it consistent with its former
behavior.

Manual rebase of #1547

openerp/addons/base/tests/test_orm.py

@@ -166,6 +166,12 @@ class TestInherits(common.TransactionCase):
         self.partner = self.registry('res.partner')
         self.user = self.registry('res.users')
 
+    def test_default(self):
+        """ `default_get` cannot return a dictionary or a new id """
+        defaults = self.user.default_get(self.cr, UID, ['partner_id'])
+        if 'partner_id' in defaults:
+            self.assertIsInstance(defaults['partner_id'], (bool, int, long))
+
     def test_create(self):
         """ creating a user should automatically create a new partner """
         partners_before = self.partner.search(self.cr, UID, [])

openerp/fields.py

@@ -1322,7 +1322,7 @@ class Many2one(_Relational):
             return value.id
 
     def convert_to_write(self, value, target=None, fnames=None):
-        return bool(value) and (value.id or value._convert_to_write(value._cache))
+        return value.id
 
     def convert_to_onchange(self, value):
         return value.id

openerp/models.py

@@ -1299,7 +1299,12 @@ class BaseModel(object):
                 record[name]            # force evaluation of defaults
 
         # retrieve defaults from record's cache
-        return self._convert_to_write(record._cache)
+        result = self._convert_to_write(record._cache)
+        for key, val in result.items():
+            if isinstance(val, NewId):
+                del result[key]         # ignore new records in defaults
+
+        return result
 
     def add_default_value(self, field):
         """ Set the default value of `field` to the new record `self`.
@@ -3951,11 +3956,6 @@ class BaseModel(object):
 
             record_id = tocreate[table].pop('id', None)
 
-            if isinstance(record_id, dict):
-                # Shit happens: this possibly comes from a new record
-                tocreate[table] = dict(record_id, **tocreate[table])
-                record_id = None
-
             # When linking/creating parent records, force context without 'no_store_function' key that
             # defers stored functions computing, as these won't be computed in batch at the end of create().
             parent_context = dict(context)