[REF] core: combine default_get() with first onchange()

When creating a new record, the client calls `default_get()`, completes
the returned values with `False`, and calls `onchange()` to apply the
onchange to the defaults.

Optimize the double round-trip by integrating `default_get()` inside
`onchange()` for the first call.  The method is called with an empty
list of fields, and usually no field values, except for records in a
one2many field.  In this case, `onchange()` does both steps above.

Task 2261084

1 files changed, 2 insertions, 2 deletions

diff --git a/odoo/addons/test_testing_utilities/tests/test_form_impl.py b/odoo/addons/test_testing_utilities/tests/test_form_impl.py
index af49d27cbe5..ab846bda87e 100644
--- a/odoo/addons/test_testing_utilities/tests/test_form_impl.py
+++ b/odoo/addons/test_testing_utilities/tests/test_form_impl.py
@@ -374,13 +374,13 @@ class TestO2M(TransactionCase):
 
         with f.subs.edit(index=0) as s:
             self.assertEqual(s.v, 5)
-            self.assertEqual(s.value, False)
+            self.assertEqual(s.value, 2)
 
         r = f.save()
 
         self.assertEqual(
             [get(s) for s in r.subs],
-            [("5", 0, 5)]
+            [("5", 2, 5)]
         )
 
     def test_o2m_inner_default(self):