[FIX] base: virtual group fields on users with new default/onchange

* override `onchange` in res.users in order to properly generate and
  send the reified group fields alongside the rest: while default_get
  sets them up, those fields then get stripped by the onchange
  machinery as they don't actually exist on the model
* add a test to check for it
* fix SSF in relation with the new default/onchange system
  - because fields may not actually exist on the record,
    `record_to_values` needs to `read` the record data rather than
    directly access the recordset: the recordset likely will not
    know about fake fields
  - after the initial onchange has run the form must be filled with
    falsy values in case the onchange has not sent defaults for
    everything
  - on creation, all fields in the form should be considered modified

Task 2341153

closes odoo/odoo#57987

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/odoo/addons/base/models/res_users.py b/odoo/addons/base/models/res_users.py
index e642e4d5c30..903007e4db0 100644
--- a/odoo/addons/base/models/res_users.py
+++ b/odoo/addons/base/models/res_users.py
@@ -1387,6 +1387,16 @@ class UsersView(models.Model):
         self._add_reified_groups(group_fields, values)
         return values
 
+    def onchange(self, values, field_name, field_onchange):
+        field_onchange['groups_id'] = ''
+        result = super().onchange(values, field_name, field_onchange)
+        if not field_name: # merged default_get
+            self._add_reified_groups(
+                filter(is_reified_group, field_onchange),
+                result.setdefault('value', {})
+            )
+        return result
+
     def read(self, fields=None, load='_classic_read'):
         # determine whether reified groups fields are required, and which ones
         fields1 = fields or list(self.fields_get())