Migrating between version control systems can be a complicated process, and Bazaar has extensive documentation on the process at http://doc.bazaar.canonical.com/migration/en and we won’t attempt to repeat that here. We will try to give a few motivating examples for conversion from Mercurial and Subversion.
In many projects wishing to use Bazaar, there is pre-existing history for the codebase that should be taken into consideration. Bazaar leverages an interchange format originally developed for Git called fast-import to provide migration strategies for many other version control systems.
The way that fast-import can be used for migration is to export the existing
history into a fast-import file, then use the
brz fast-import command.
The fastimport plugin includes exporters for Subversion, CVS, Git, Mercurial
and darcs, accessible as the
fast-export-from-XXX commands. Note that
fast-import should not be used in a branch with existing history.
Assuming that ProjectX was first developed in Mercurial before switching to
Bazaar, and that the Mercurial repository is in
following commands will import that history into a newly created
branch. (Recall that in Further Configuration we created the
/srv/bzr/projectx directory as a shared repository.)
$ cd /srv/bzr/projectx $ brz fast-export-from-hg ../../hg/projectx projectx.fi $ brz init trunk $ brz fast-import projectx.fi trunk
As the most common centralized version control system, migration from
Subversion is particularly important for any new version control system.
Bazaar’s svn plugin provides tools for interaction with Subversion
projects. In fact, Bazaar can be used transparently with projects stored in
Subversion, but that is beyond the scope of this document. (See
more on that subject.) What is relevant here is the
provided by that plugin. This can import an entire subversion repository
including tags and branches, particularly if they are stored in Subversion’s
recommended directory structure:
This command has flexible ways to specify what paths within the Subversion
repository contain branches and which contain tags. For example, the
recommended layout for Subversion projects (called
trunk by the svn
plugin) could be specified in
[203ae883-c723-44c9-aabd-cb56e4f81c9a] branches = branches/* tags = tags/*
This allows substantially complicated Subversion repositories to be converted
into a set of separate Bazaar branches. After installing the svn plugin, see
brz help svn-import and
brz help svn-layout.