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

Overview
--------

This document describes ways of using ``bzr version-info`` as part of a
build process to embed version information into a final project.


Python project
--------------

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:
        bzr 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``.

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``, ``bzr`` 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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