[FIX] base: Allow to create an user

Now that an onchange set its result into the cache, we
cannot create a user because the onchange tries to put
the reified fields (eg: sel_4_7) into the cache.

As those field don't exist and are pseudo-fields used
to manage groups into the res user form view, we should
replace the values by ORM commands on the groups_id field,
as this is already the case in the create and the write
methods.

Note: Initially merged in saas-12.4, but was not
forward ported, I don't know why.

closes odoo/odoo#34487

Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>

odoo/addons/base/models/res_users.py

@@ -1192,6 +1192,18 @@ class UsersView(models.Model):
                     user.write({'groups_id': [(4, group_multi_company.id)]})
         return res
 
+    @api.model
+    def new(self, values={}, origin=None, ref=None):
+        values = self._remove_reified_groups(values)
+        user = super().new(values=values, origin=origin, ref=ref)
+        group_multi_company = self.env.ref('base.group_multi_company', False)
+        if group_multi_company and 'company_ids' in values:
+            if len(user.company_ids) <= 1 and user.id in group_multi_company.users.ids:
+                user.update({'groups_id': [(3, group_multi_company.id)]})
+            elif len(user.company_ids) > 1 and user.id not in group_multi_company.users.ids:
+                user.update({'groups_id': [(4, group_multi_company.id)]})
+        return user
+
     def _remove_reified_groups(self, values):
         """ return `values` without reified group fields """
         add, rem = [], []