[FIX] base: restrict state selection to the selected country

It was not an issue before as there where only the US states in the data.
Remove onchange as useless since domain restriction.

Fixes #13657

odoo/addons/base/res/res_partner.py

@@ -350,11 +350,6 @@ class Partner(models.Model, FormatAddress):
                 result['value'] = {key: convert(self.parent_id[key]) for key in address_fields}
         return result
 
-    @api.onchange('state_id')
-    def onchange_state(self):
-        if self.state_id:
-            self.country_id = self.state_id.country_id
-
     @api.onchange('email')
     def onchange_email(self):
         if not self.image and not self._context.get('yaml_onchange') and self.email:

odoo/addons/base/res/res_partner_view.xml

@@ -110,7 +110,9 @@
                                 <field name="street" placeholder="Street..." class="o_address_street"/>
                                 <field name="street2" placeholder="Street 2..." class="o_address_street"/>
                                 <field name="city" placeholder="City" class="o_address_city"/>
-                                <field name="state_id" class="o_address_state" placeholder="State" options='{"no_open": True}'/>
+                                <field name="state_id" class="o_address_state" placeholder="State"
+                                       options='{"no_open": True}'
+                                       domain="[('country_id', '=', country_id')]"/>
                                 <field name="zip" placeholder="ZIP" class="o_address_zip"/>
                                 <field name="country_id" placeholder="Country" class="o_address_country" options='{"no_open": True, "no_create": True}'/>
                             </div>
@@ -173,7 +175,9 @@
                                 <field name="city" placeholder="City" class="o_address_city"
                                     attrs="{'readonly': [('type', '=', 'contact'),('parent_id', '!=', False)]}"/>
                                 <field name="state_id" class="o_address_state" placeholder="State" options='{"no_open": True}'
-                                    attrs="{'readonly': [('type', '=', 'contact'),('parent_id', '!=', False)]}" context="{'country_id': country_id, 'zip': zip}"/>
+                                    attrs="{'readonly': [('type', '=', 'contact'),('parent_id', '!=', False)]}"
+                                    context="{'country_id': country_id, 'zip': zip}"
+                                    domain="[('country_id', '=', country_id')]"/>
                                 <field name="zip" placeholder="ZIP" class="o_address_zip"
                                     attrs="{'readonly': [('type', '=', 'contact'),('parent_id', '!=', False)]}"/>
                                 <field name="country_id" placeholder="Country" class="o_address_country" options='{"no_open": True, "no_create": True}'