============
Bug Trackers
============

Bazaar has a facility that allows you to associate a commit with a bug
in the project's bug tracker. Other tools can then use this information
to link between the commit and the bug, or to automatically mark the bug
closed in the branches that contain the commit.

Associating Commits and Bugs
============================

When you make a commit you can assiociate it with a bug by using the
``--fixes`` option of ``commit``. For example::

    $ bzr commit --fixes 12345 -m 'Properly close the connection on errors'

This will set a revision property on the revision that is committed
which contains the URI at which more information on the bug can be found.
Bazaar itself does no more than this, but once the information is recorded
other tools can make use of it.

Configuration of the Bug Tracker
================================

As each project has it's own bug tracker, and there are many different
bug tracking systems you must first do some configuration before you
can use this system.

Bazaar currently implements support for projects that use Bugzilla or
Trac to manage their bugs. If your project uses a different system it
is easy to add support for the system, perhaps through a plugin.

If you do use Bugzilla or Trac then you only need to set a configuration
variable which contains the base URL of the bug tracker. These options
can go into ``bazaar.conf``, ``branch.conf`` or into a branch-specific
configuration section in ``locations.conf``.

You can set up these values for each of the projects you work on in
``bazaar.conf``, as you specify a short name for each so that you
can specify which you mean at commit time.

bugzilla_<tracker_abbreviation>_url
-----------------------------------
If present, the location of the Bugzilla bug tracker referred to by
<tracker_abbreviation>. This option can then be used together with ``bzr commit
--fixes`` to mark bugs in that tracker as being fixed by that commit. For
example::

    bugzilla_squid_url = http://www.squid-cache.org/bugs

would allow ``bzr commit --fixes squid:1234`` to mark Squid's bug 1234 as
fixed.

trac_<tracker_abbrevation>_url
------------------------------
If present, the location of the Trac instance referred to by
<tracker_abbreviation>. This option can then be used together with ``bzr commit
--fixes`` to mark bugs in that tracker as being fixed by that commit. For
example::

    trac_twisted_url = http://www.twistedmatrix.com/trac

would allow ``bzr commit --fixes twisted:1234`` to mark Twisted's bug 1234 as
fixed.

Limitations of the system
=========================

This method of associating revisions and bugs does have some limitations. The
first is that the association can only be made at commit time. This means that
if you forget to make the association when you commit, or the bug is reported
after you fix it you cannot go back and add the link later.

Related to this is the fact that the association is immutable. If a bug is
marked as fixed by one commit, but that revision does not fully solve the
bug, or there is a later regression you cannot go back and remove the link.