ticket hierarchy

[mrovner@…]

At this moment it is difficult to manage a long list of interdependent issues. Ideally we would have something like

#122
  |_ #111
  |_ #128
#762
  |_ #215
  |   |_ #212
  |_ #422 

However tree is not enough, 1.2 might as well depend on 2.1.2. So directed acyclic graph will be better.

To approach implementation, we might have (custom) field "depends on" with list of tickets and trac.ticket.api.ITicketChangeListener extension point (new), which will maintain the graph and possibly provide some cool features like:

• auto priority bump down the tree
• auto notify ticket owner(s) when child ticket closes and release parent ticket from hold (new state meaning waiting for dependent tickets).