[IMP] Move domain in python in order to allow inheritance

mail_attach_existing_attachment/wizard/mail_compose_message.py

@@ -38,11 +38,16 @@ class MailComposeMessage(models.TransientModel):
             res['can_attach_attachment'] = True  # pragma: no cover
         return res
 
+    @api.model
+    def _get_object_attachment_domain(self):
+        return "[('res_model', '=', model), ('res_id', '=', res_id)]"
+
     can_attach_attachment = fields.Boolean(string='Can Attach Attachment')
     object_attachment_ids = fields.Many2many(
         comodel_name='ir.attachment',
         relation='mail_compose_message_ir_attachments_object_rel',
-        column1='wizard_id', column2='attachment_id', string='Attachments')
+        column1='wizard_id', column2='attachment_id', string='Attachments',
+        domain=lambda self: self._get_object_attachment_domain())
 
     @api.multi
     def get_mail_values(self, res_ids):

mail_attach_existing_attachment/wizard/mail_compose_message_view.xml

@@ -9,7 +9,7 @@
                 <field name="can_attach_attachment" invisible="1"/>
                 <div attrs="{'invisible': [('can_attach_attachment', '=', False)]}">
                     <br />
-                    <field name="object_attachment_ids" widget="many2many_checkboxes" domain="[('res_model', '=', model), ('res_id', '=', res_id)]" />
+                    <field name="object_attachment_ids" widget="many2many_checkboxes" />
                 </div>
             </xpath>
         </field>