Notes
=====
Adds basic ticket dependencies for Trac.

Note: MasterTickets 3.0 requires Trac 0.12 or higher.

What is it?
-----------
This plugin adds "blocking" and "blockedby" fields to each ticket, enabling you
to express dependencies between tickets. It also provides a graphviz-based
dependency-graph feature for those tickets having dependencies specified,
allowing you to visually understand the dependency tree. The dependency graph
is viewable by clicking 'depgraph' in the context (in the upper right corner)
menu when viewing a ticket that blocks or is blocked by another ticket.

What is it not?
---------------
* It does not provide ticket-hiding for sub-tasks of a top-level ticket.  

  * There is no orthogonal parent/child relationship possible

  * You cannot view the descriptions of tickets depending on the current
    ticket

  * In fact, there are no explicit features that can assist you with sub-task
    management

  * Although it would be cool.

* It does not allow you to create a dependent ticket from the current ticket

* It does not include reporting features to show how tasks are interrelated
  (other than the dependency graph already described above).

Configuration
=============
To use this plugin you must configure two custom fields named ``blocking``
and ``blockedby``.

All other configuration options go in the ``[mastertickets]`` section.

``dot_path`` : *optional, default: dot*
    Path to the dot executable. This is only used for the dependency graph.

``use_gs`` : *optional, default: False*
    If enabled, use ghostscript to produce a nicer dependency graph.

``gs_path`` : *optional, default: gs*
    Path to the ghostscript executable.

``closed_color`` : *optional, default: green*
    Color of closed tickets

``opened_color`` : *optional, default: red*
    Color of opened tickets

``graph_direction`` : *optional, default: TD*
	Direction of the dependency graph (TD = Top Down, DT = Down Top, LR = Left Right, RL = Right Left)


To enable the plugin::

    [components]
    mastertickets.* = enabled
    
    [ticket-custom]
    blocking = text
    blocking.label = Blocking
    blockedby = text
    blockedby.label = Blocked By

Custom fields
-------------
While the two field names must be ``blocking`` and ``blocked_by``, you are
free to use any text for the field labels.

Example
=======

To use a locally-built graphviz::

    [mastertickets]
    dot_path = /usr/local/bin/dot
    
    [components]
    mastertickets.* = enabled
    
    [ticket-custom]
    blocking = text
    blocking.label = Blocking
    blockedby = text
    blockedby.label = Blocked By


Example reports
--------------

To only show the tickets that are currently not blocked by other non-closed
tickets, use this SQL (eg in a new report):

SELECT p.value AS __color__,
   id AS ticket, summary, component, version, milestone, t.type AS type, 
   owner, status,
   time AS created,
   changetime AS _changetime, description AS _description,
   reporter AS _reporter,
   (SELECT COUNT(*) FROM mastertickets m, ticket t2 WHERE t.id=m.dest AND m.source=t2.id AND t2.status <> 'closed') AS _blocked
  FROM ticket t
  LEFT JOIN enum p ON p.name = t.priority AND p.type = 'priority'
  WHERE status <> 'closed' AND _blocked = 0
  ORDER BY CAST(p.value AS integer), milestone, t.type, time

Basically it is the default report, with an aditional, hidden field (the sub query),
named _blocked.  The value of this field is checked to be zero.

Using this method, other reports can be modified as well, eg to show the number of tickets
blocking a ticket and/or the number of tickets that the ticked is blocking itself.
