Do not use init values for new record without id to compute the changed values

When using new instance to fill a xxx2Many field, all the values must be
considered as changed and we should not expect any initial value.

Closes #13716

trytond/trytond/model/model.py

@@ -284,6 +284,8 @@ class Model(URLMixin, PoolBase, metaclass=ModelMeta):
             id = int(id)
         self._id = id
         self._deleted = self._removed = None
+        self._values = None
+        self._init_values = None
         if kwargs:
             self._values = self._record()
             parent_values = defaultdict(dict)
@@ -305,10 +307,8 @@ class Model(URLMixin, PoolBase, metaclass=ModelMeta):
             # to ensure it was evaluated with all the fields
             for name, value in has_context.items():
                 setattr(self, name, value)
-            self._init_values = self._values._copy()
-        else:
-            self._values = None
-            self._init_values = None
+            if id is not None:
+                self._init_values = self._values._copy()
 
     def __copy__(self):
         copied = self.__class__(self.id)

trytond/trytond/model/modelview.py

@@ -870,7 +870,9 @@ class ModelView(Model):
                         value = value.id
             elif field._type in ['one2many', 'many2many']:
                 targets = value
-                if fname in init_values:
+                if self.id is None:
+                    init_targets = []
+                elif fname in init_values:
                     init_targets = init_values._get(fname)
                 elif isinstance(field, fields.Function):
                     init_targets = []
@@ -898,14 +900,7 @@ class ModelView(Model):
                                     value['update'].append(target_changed)
                         else:
                             if isinstance(target, ModelView):
-                                # Ensure initial values are returned because
-                                # target was instantiated on server side.
-                                target_init_values = target._init_values
-                                target._init_values = None
-                                try:
-                                    added_values = target._changed_values()
-                                finally:
-                                    target._init_values = target_init_values
+                                added_values = target._changed_values()
                             else:
                                 added_values = target._default_values
                             added_values['id'] = target.id

trytond/trytond/tests/test_modelview.py

@@ -185,7 +185,7 @@ class ModelView(TestCase):
         Model = pool.get('test.modelview.changed_values')
         Target = pool.get('test.modelview.changed_values.target')
 
-        record = Model(targets=[], m2m_targets=[], m2m_function=[])
+        record = Model(id=-1, targets=[], m2m_targets=[], m2m_function=[])
 
         self.assertEqual(record._changed_values(), {})
 
@@ -208,7 +208,7 @@ class ModelView(TestCase):
                 'dictionary': {'key': 'value'},
                 })
 
-        record = Model(name='test', target=1, targets=[
+        record = Model(id=-1, name='test', target=1, targets=[
                 {'id': 1, 'name': 'foo'},
                 {'id': 2},
                 ],
@@ -243,7 +243,7 @@ class ModelView(TestCase):
                 })
 
         # change only one2many record
-        record = Model(targets=[{'id': 1, 'name': 'foo'}])
+        record = Model(id=-1, targets=[{'id': 1, 'name': 'foo'}])
         self.assertEqual(record._changed_values(), {})
 
         target, = record.targets
@@ -256,7 +256,7 @@ class ModelView(TestCase):
                 })
 
         # no initial value
-        record = Model(targets=[], m2m_targets=[], m2m_function=[])
+        record = Model(id=-1, targets=[], m2m_targets=[], m2m_function=[])
         record._values = record._record()
         target = Target(id=1)
         record._values['targets'] = [target]
@@ -267,6 +267,34 @@ class ModelView(TestCase):
                     },
                 })
 
+    @with_transaction()
+    def test_changed_values_with_no_id(self):
+        "Test changed values with no id"
+        pool = Pool()
+        Model = pool.get('test.modelview.changed_values')
+        Target = pool.get('test.modelview.changed_values.target')
+
+        record = Model(
+            name='foo',
+            target=Target(1),
+            ref_target=Target(2),
+            targets=[Target(name='bar')],
+            multiselection=['a'],
+            dictionary={'key': 'value'})
+
+        self.assertEqual(record._changed_values(), {
+                'name': 'foo',
+                'target': 1,
+                'ref_target': 'test.modelview.changed_values.target,2',
+                'targets': {
+                    'add': [
+                        (0, {'id': None, 'name': 'bar'}),
+                        ],
+                    },
+                'multiselection': ('a',),
+                'dictionary': {'key': 'value'},
+                })
+
     @with_transaction()
     def test_changed_values_2many_function(self):
         "Test changed values for xxx2many function field"
@@ -315,7 +343,7 @@ class ModelView(TestCase):
         Target = pool.get('test.modelview.changed_values.target')
 
         target = Target(1)
-        record = Model(targets=[target])
+        record = Model(id=-1, targets=[target])
         Model.targets.remove(record, [target])
 
         self.assertEqual(record._changed_values(), {
@@ -332,7 +360,7 @@ class ModelView(TestCase):
         Target = pool.get('test.modelview.changed_values.target')
 
         target = Target(1)
-        record = Model(m2m_targets=[target])
+        record = Model(id=-1, m2m_targets=[target])
         Model.m2m_targets.delete(record, [target])
 
         self.assertEqual(record._changed_values(), {