[IMP] models: in `onchange`, keep track of virtual ids of new records

The x2many "create" command is now like: `(0, ref, vals)`, where `ref` is an
arbitrary reference that may be used to identify a new line in the relation.
The reference is returned in a similar command by the method `onchange`.
`onchange` now supports self-modifying x2many fields.

3 files changed, 59 insertions, 11 deletions

diff --git a/odoo/addons/test_new_api/tests/test_onchange.py b/odoo/addons/test_new_api/tests/test_onchange.py
index a6e2bff1b35..dfeafd99805 100644
--- a/odoo/addons/test_new_api/tests/test_onchange.py
+++ b/odoo/addons/test_new_api/tests/test_onchange.py
@@ -157,6 +157,51 @@ class TestOnChange(common.TransactionCase):
             }),
         ])
 
+    def test_onchange_one2many_reference(self):
+        """ test the effect of onchange() on one2many fields with line references """
+        BODY = "What a beautiful day!"
+        USER = self.env.user
+        REFERENCE = "virtualid42"
+
+        field_onchange = self.Discussion._onchange_spec()
+        self.assertEqual(field_onchange.get('name'), '1')
+        self.assertEqual(field_onchange.get('messages'), '1')
+        self.assertItemsEqual(
+            strip_prefix('messages.', field_onchange),
+            ['author', 'body', 'name', 'size', 'important'],
+        )
+
+        # modify discussion name, and check that the reference of the new line
+        # is returned
+        values = {
+            'name': "Foo",
+            'categories': [],
+            'moderator': False,
+            'participants': [],
+            'messages': [
+                (0, REFERENCE, {
+                    'name': "[%s] %s" % ('', USER.name),
+                    'body': BODY,
+                    'author': USER.id,
+                    'size': len(BODY),
+                    'important': False,
+                }),
+            ],
+        }
+        self.env.invalidate_all()
+        result = self.Discussion.onchange(values, 'name', field_onchange)
+        self.assertIn('messages', result['value'])
+        self.assertItemsEqual(result['value']['messages'], [
+            (5,),
+            (0, REFERENCE, {
+                'name': "[%s] %s" % ("Foo", USER.name),
+                'body': BODY,
+                'author': USER.name_get()[0],
+                'size': len(BODY),
+                'important': False,
+            }),
+        ])
+
     def test_onchange_one2many_multi(self):
         """ test the effect of multiple onchange methods on one2many fields """
         partner = self.env.ref('base.res_partner_1')
diff --git a/odoo/fields.py b/odoo/fields.py
index 43ee8edbad1..d5638541b48 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -2028,7 +2028,7 @@ class _RelationalMulti(_Relational):
             for command in value:
                 if isinstance(command, (tuple, list)):
                     if command[0] == 0:
-                        ids.add(comodel.new(command[2]).id)
+                        ids.add(comodel.new(command[2], command[1]).id)
                     elif command[0] == 1:
                         comodel.browse(command[1]).update(command[2])
                         ids.add(command[1])
@@ -2085,7 +2085,7 @@ class _RelationalMulti(_Relational):
         for record in value:
             vals = {name: convert(record[name], record) for name, convert in converters}
             if not record.id:
-                result.append((0, 0, vals))
+                result.append((0, record.id.ref or 0, vals))
             elif vals:
                 result.append((1, record.id, vals))
             else:
diff --git a/odoo/models.py b/odoo/models.py
index c589d4805fd..4e0ca389651 100644
--- a/odoo/models.py
+++ b/odoo/models.py
@@ -168,7 +168,12 @@ class MetaModel(api.Meta):
 
 
 class NewId(object):
-    """ Pseudo-ids for new records. """
+    """ Pseudo-ids for new records, encapsulating an optional reference. """
+    __slots__ = ['ref']
+
+    def __init__(self, ref=None):
+        self.ref = ref
+
     def __bool__(self):
         return False
     __nonzero__ = __bool__
@@ -4445,14 +4450,17 @@ class BaseModel(MetaModel('DummyModel', (object,), {'_register': False})):
     #
 
     @api.model
-    def new(self, values={}):
+    def new(self, values={}, ref=None):
         """ new([values]) -> record
 
         Return a new record instance attached to the current environment and
         initialized with the provided ``value``. The record is *not* created
         in database, it only exists in memory.
+
+        One can pass a reference value to identify the record among other new
+        records. The reference is encapsulated in the ``id`` of the record.
         """
-        record = self.browse([NewId()])
+        record = self.browse([NewId(ref)])
         record._cache.update(record._convert_to_cache(values, update=True))
 
         if record.env.in_onchange:
@@ -4978,12 +4986,6 @@ class BaseModel(MetaModel('DummyModel', (object,), {'_register': False})):
                         todo.append(name)
                         dirty.add(name)
 
-        # At the moment, the client does not support updates on a *2many field
-        # while this one is modified by the user.
-        if isinstance(field_name, pycompat.string_types) and \
-                self._fields[field_name].type in ('one2many', 'many2many'):
-            dirty.discard(field_name)
-
         # collect values from dirty fields
         result['value'] = {
             name: self._fields[name].convert_to_onchange(record[name], record, subfields[name])
@@ -4991,6 +4993,7 @@ class BaseModel(MetaModel('DummyModel', (object,), {'_register': False})):
         }
 
         return result
+
 collections.Set.register(BaseModel)
 # not exactly true as BaseModel doesn't have __reversed__, index or count
 collections.Sequence.register(BaseModel)