[FIX] mail: set message_main_attachment_id when the attachment is added via widget

Create a record.
Add an attachment, using the widget (aptly named 'add an attachment').
It is not set as message_main_attachment_id.
If you add the message through 'log note', then it is.

We add a hook to make sure that it is set as message_main_attachment_id
when added through the widget.

opw 1950403

closes odoo/odoo#31847

Signed-off-by: Nans Lefebvre (len) <len@odoo.com>

addons/mail/models/ir_attachment.py

@@ -7,6 +7,14 @@ from odoo import api, fields, models
 class IrAttachment(models.Model):
     _inherit = 'ir.attachment'
 
+    @api.multi
+    def _post_add_create(self):
+        """ Overrides behaviour when the attachment is created through the controller
+        """
+        super(IrAttachment, self)._post_add_create()
+        for record in self:
+            record.register_as_main_attachment()
+
     def register_as_main_attachment(self):
         """ Registers this attachment as the main one of the model it is
         attached to.

addons/web/controllers/main.py

@@ -1167,6 +1167,7 @@ class Binary(http.Controller):
                     'res_model': model,
                     'res_id': int(id)
                 })
+                attachment._post_add_create()
             except Exception:
                 args.append({'error': _("Something horrible happened")})
                 _logger.exception("Fail to upload attachment %s" % ufile.filename)

odoo/addons/base/models/ir_attachment.py

@@ -506,6 +506,10 @@ class IrAttachment(models.Model):
             self.browse().check('write', values=values)
         return super(IrAttachment, self).create(vals_list)
 
+    @api.multi
+    def _post_add_create(self):
+        pass
+
     @api.one
     def generate_access_token(self):
         if self.access_token: