Exporting version information
=============================

Getting the last revision number
--------------------------------

If you only need the last revision number in your build scripts, you can
use the ``revno`` command to get that value like this::

  $ brz revno
  3104


Getting more version information
--------------------------------

The ``version-info`` command can be used to output more information
about the latest version like this::

  $ brz version-info
  revision-id: pqm@pqm.ubuntu.com-20071211175118-s94sizduj201hrs5
  date: 2007-12-11 17:51:18 +0000
  build-date: 2007-12-13 13:14:51 +1000
  revno: 3104
  branch-nick: brz.dev

You can easily filter that output using operating system tools or
scripts. For example::

  $ brz version-info | grep ^date
  date: 2007-12-11 17:51:18 +0000

The ``--all`` option will actually dump version information about
every revision if you need that information for more advanced
post-processing.


Python projects
---------------

.. TODO: Figure out how to attach into ``setup.py``


If using a Makefile to build your project, you can generate the version
information file as simply as::

  library/_version.py:
        brz version-info --format python > library/_version.py

This generates a file which contains 3 dictionaries:

  * `version_info`: A dictionary containing the basic information about the
    current state.

  * `revisions`: A dictionary listing all of the revisions in the
    history of the tree, along with the commit times and commit
    message.  This defaults to being empty unless ``--all`` or
    ``--include-history`` is supplied. This is useful if you want to
    track what bug fixes, etc, might be included in the released
    version. But for many projects it is more information than needed.

  * `file_revisions`: A dictionary listing the last-modified revision
    for all files in the project. This can be used similarly to how
    ``$Id$`` keywords are used in CVS-controlled files. The last
    modified date can be determined by looking in the ``revisions``
    map. This is also empty by default, and enabled only by ``--all``
    or ``--include-file-revisions``.


Getting version info in other formats
-------------------------------------

Breezy supports a template-based method for getting version information in
arbitrary formats.  The ``--custom`` option to ``version-info`` can be
used by providing a ``--template`` argument that contains variables that
will be expanded based on the status of the working tree.  For example, to
generate a C header file with a formatted string containing the current
revision number::

 brz version-info --custom \
      --template="#define VERSION_INFO \"Project 1.2.3 (r{revno})\"\n" \
      > version_info.h

where the ``{revno}`` will be replaced by the revision number of the
working tree.  (If the example above doesn't work on your OS, try
entering the command all on one line.) For more information on the
variables that can be used in templates, see `Version Info`_ in the
Breezy User Reference.

.. _Version Info: ../user-reference/index.html#version-info

Predefined formats for dumping version information in specific languages
are currently in development. Please contact us on the mailing list about
your requirements in this area.

Check clean
-----------

Most information about the contents of the project can be cheaply
determined by just reading the revision entry. However, it can be useful
to know if the working tree was completely up-to-date when it was
packaged, or if there was a local modification. By supplying either
``--all`` or ``--check-clean``, ``brz`` will inspect the working tree, and
set the ``clean`` flag in ``version_info``, as well as set entries in
``file_revisions`` as ``modified`` where appropriate.

..
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