TicketValidation is a plug-in for Trac that adds support for conditionally required or hidden fields. The plug-in allows you to make built-in or custom fields required or hidden based on configurable boolean conditions.

Install the TicketValidation plug-in:

$ easy_install -Z https://www.matbooth.co.uk/svn/trunk/ticketvalidation/

Ensure the plug-in is enabled in trac.ini:

[components]
ticketvalidation.* = enabled

Once configured, Trac administrators will find a new ticket system admin panel for maintaining ticket validation rules.