[IMP] base: choice of state/country easier in banks and partners

OPW 1891131
closes #27497

When creating a new bank account/partner address, the view displays the 'state 'field before the 'country_id'  field, which naturally leads users to select the state before selecting the country.
But there was problem: in order to select a state, one had to first select a country, which was confusing.

Done:
  - allow the user to select the state before the country (without restriction on country)
  - remove the state from the form when the country changes, if the state (name) is not in the country
  - automatically set the country when the state is set
  - always display the country code in the name_get of res.country.state, to deal with the case where different countries have a state with the same name

odoo/addons/base/models/res_bank.py

@@ -26,7 +26,7 @@ class Bank(models.Model):
     street2 = fields.Char()
     zip = fields.Char()
     city = fields.Char()
-    state = fields.Many2one('res.country.state', 'Fed. State', domain="[('country_id', '=', country)]")
+    state = fields.Many2one('res.country.state', 'Fed. State', domain="[('country_id', '=?', country)]")
     country = fields.Many2one('res.country')
     email = fields.Char()
     phone = fields.Char()
@@ -52,6 +52,16 @@ class Bank(models.Model):
                 domain = ['&'] + domain
         bank_ids = self._search(domain + args, limit=limit, access_rights_uid=name_get_uid)
         return self.browse(bank_ids).name_get()
+        
+    @api.onchange('country')
+    def _onchange_country_id(self):
+        if self.country and self.country != self.state.country_id:
+            self.state = False
+            
+    @api.onchange('state')
+    def _onchange_state(self):
+        if self.state.country_id:
+            self.country = self.state.country_id
 
 
 class ResPartnerBank(models.Model):

odoo/addons/base/models/res_country.py

@@ -128,3 +128,10 @@ class CountryState(models.Model):
         search_domain.append(('id', 'not in', first_state_ids))
         state_ids = first_state_ids + self._search(search_domain + args, limit=limit, access_rights_uid=name_get_uid)
         return [(state.id, state.display_name) for state in self.browse(state_ids)]
+
+    @api.multi
+    def name_get(self):
+        result = []
+        for record in self:
+            result.append((record.id, "{} ({})".format(record.name, record.country_id.code)))
+        return result

odoo/addons/base/models/res_partner.py

@@ -191,7 +191,7 @@ class Partner(models.Model):
     street2 = fields.Char()
     zip = fields.Char(change_default=True)
     city = fields.Char()
-    state_id = fields.Many2one("res.country.state", string='State', ondelete='restrict')
+    state_id = fields.Many2one("res.country.state", string='State', ondelete='restrict', domain="[('country_id', '=?', country_id)]")
     country_id = fields.Many2one('res.country', string='Country', ondelete='restrict')
     email = fields.Char()
     email_formatted = fields.Char(
@@ -364,10 +364,13 @@ class Partner(models.Model):
 
     @api.onchange('country_id')
     def _onchange_country_id(self):
-        if self.country_id:
-            return {'domain': {'state_id': [('country_id', '=', self.country_id.id)]}}
-        else:
-            return {'domain': {'state_id': []}}
+        if self.country_id and self.country_id != self.state_id.country_id:
+            self.state_id = False
+
+    @api.onchange('state_id')
+    def _onchange_state(self):
+        if self.state_id.country_id:
+            self.country_id = self.state_id.country_id
 
     @api.onchange('email')
     def onchange_email(self):