Make ticket's old data available somehow

[ejucovy]

Currently the plugin only has access to the values of the ticket's attributes after the workflow action has been applied.

It would be nice if it could also provide access to the ticket's old values somehow. Without access to the old values, it's impossible to recreate Trac's core "ticket change" notifications using this plugin.

This should be possible to do, because the plugin's ITicketActionController.get_ticket_changes method is called, before any changes are applied, in the same request that then calls .apply_action_side_effects. So during that method, we could retrieve the ticket's values, before changes are applied, and stash them somewhere, probably on the request.

[ejucovy]

Implemented in ​this commit.

[robert.bostedt@…]

i don't understand how to access the old values

[ejucovy]

Accessing old ticket values

The ticket's old values are available in the notification templates. These values are provided in a Python dict named old_values. The values provided are from before any changes were made to the ticket, whether by workflow operations or by direct user action.

You can use this dictionary to set up a notification similar to Trac's built in ticket change email; for example:

[ticket-workflow-notifications]
ticket_changed = *
ticket_changed.body = Ticket changed by $change.author: $change.comment
                      {% for field in old_ticket %}{% if old_ticket[field] != ticket[field] %}
              $field changed: ${old_ticket[field]} => ${ticket[field]}{% end %}{% end %}
ticket_changed.recipients = $ticket.reporter
ticket_changed.subject = Ticket $ticket.id has changed!