AttributeError: 'Ticket' object has no attribute 'is_writeable_field' when using with Agilo plugin

[François Granade]

Reported on Trac ​http://trac.edgewall.org/ticket/9452 - should be here instead

Stack is:

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 450, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 176, in dispatch
    chosen_handler)
  File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 296, in _pre_process_request
    chosen_handler = filter_.pre_process_request(req, chosen_handler)
  File "/var/trac/env/venotion/plugins/BatchModify-0.6.0_trac0.11-py2.6.egg/batchmod/web_ui.py", line 47, in pre_process_request
    self._batch_modify(req)
  File "/var/trac/env/venotion/plugins/BatchModify-0.6.0_trac0.11-py2.6.egg/batchmod/web_ui.py", line 94, in _batch_modify
    t.save_changes(req.authname, comment)
  File "/usr/lib/python2.6/site-packages/trac/ticket/model.py", line 299, in save_changes
    listener.ticket_changed(self, comment, author, old_values)
  File "/usr/lib/python2.6/site-packages/binary_agilo-1.3.0.1_PRO-py2.6.egg/agilo/scrum/burndown/changelistener.py", line 69, in ticket_changed
    current_sprint_name = self._current_sprint_name(ticket)
  File "/usr/lib/python2.6/site-packages/binary_agilo-1.3.0.1_PRO-py2.6.egg/agilo/scrum/burndown/changelistener.py", line 119, in _current_sprint_name
    return self._current_value(Key.SPRINT, ticket) or None
  File "/usr/lib/python2.6/site-packages/binary_agilo-1.3.0.1_PRO-py2.6.egg/agilo/scrum/burndown/changelistener.py", line 128, in _current_value
    if not ticket.is_writeable_field(fieldname) or not ticket[fieldname]:
AttributeError: 'Ticket' object has no attribute 'is_writeable_field'

[François Granade]

In fact the problem had been already reported for the BatchModifyPlugin - see #9236