Bazaar

Bazaar

 




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Revision 110 as of 2007-05-18 16:21:13

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Introduction

This plugin allows bzr direct access to Subversion repositories. This allows bzr branch, bzr push, bzr pull, and bzr co to work directly against Subversion repositories.

The plugin can at the moment be used to commit to, pull from, merge from, push to and view logs of Subversion branches from Bazaar.

Example branches

All created by simply running bzr branch ORIGINAL-URL.

More automatically imported branches can be found at http://people.samba.org/bzr/jelmer/mirror .

If you are having problems checking out a particular branch, please file a bug report and include the branch URL (if the branch is public) and the backtrace.

Features

The following features are currently present:

  • Connecting to remote Subversion repositories over all protocols supported by Subversion itself (at present: svn://, svn+ssh://, http:// (webdav), file://) as well as dump files. Checkouts, lightweight checkouts and branching works.
  • Track Bazaar merges in Subversion. Merged revisions show up as ghosts.
  • Subversion working copies. Can be modified, queried ({{{bzr status}}} on a svn- native working copy created with {{{svn co}}} works) and committed from.
  • Committing to Subversion from Bazaar.
  • Push Bazaar revisions to Subversion. These revisions will show up in Subversion as a commit with the pushed revision as one of the parents.
  • Follow branch copies. Revision history is not truncated when a branch was copied in Subversion.
  • Efficiently uses network bandwidth.
  • Recognizes file metadata (executable bits, symlinks).
  • 'svn-import' command with functionality similar to ["svn2bzr"].
  • Ability to track merges done with SVK (http://svk.elixus.org/) and write merges from SVK/Svn branches in a format understandable by SVK.
  • Generates consistent file ids and revision ids. Two branches made using this plugin of the same Subversion branch will result in exactly the same Bazaar branch.
  • Handles complex operations in Subversion: committing to two branches at once, upgrading directories to branches, . copies from early revisions, ...

Future Enhancements

In the future, I also hope to support:

Features

  • Renames. Initial work has been done to support this, but the number of corner cases is wide, so support for this . has not been enabled by default yet.
  • "True" push. This requires storing the Bazaar inventory and revision in Subversion revision properties. . Ideally, revision id aliases would have to be used so the revision id that is being 'overriden' can still exist. Once this is implemented, it would also be possible and make sense to store GPG signatures for commits in Subversion branches. This might require also storing 'bzr:inventory' and 'bzr:revision' properties in order to make sure the sha1's for a revision keep matching. http://people.samba.org/bzr/jelmer/bzr-svn/customrevids
  • Proper Windows support. Most of the code depends on '/' being the path separator at the moment.
  • 'svn:externals'. Externals should be mapped to Bazaar 'by-reference' nested branches and the other way around. Work on progress in http://people.samba.org/bzr/jelmer/bzr-svn/nestedtrees
  • tags

Performance

Network-wise (both bandwidth and roundtrips), the plugin is in good shape. However, it is currently quite CPU-intensive for no good reason and I hope to make a couple of improvements in that area. * More efficient use of CPU

  • Override implementation of get_revision_delta(). Will speed up 'bzr log -v'
  • use svn_ra_replay() on systems that have Subversion 1.4. Saves a couple of roundtrips when fetching history. Initial work in branch at http://people.samba.org/bzr/jelmer/bzr-svn/replay
  • implement svn_ra_get_dir_revs() in Subversion to fetch the properties set on a specific directory all at once.
  • Something in Subversion or the Python-Subversion bindings appears to be leaking a lot of memory.

Properties

Some Subversion properties can currently not be represented in Bazaar and are therefore ignored for the time being:

  • 'svn:ignore' is not imported. There should be a `Repository.get_ignores(revid)' call in Bazaar rather than a magic '.bzrignore' file. Spec at https://launchpad.net/products/bzr/+spec/new-ignore-rules

    System Message: WARNING/2 (<string>, line 120); backlink

    Inline interpreted text or phrase reference start-string without end-string.

  • 'svn:mime-type'

  • 'svn:eol-style'. Requires eol support in Bazaar.

  • 'svn:keywords'. Requires keywords support in Bazaar. Spec at https://launchpad.net/products/bzr/+spec/bzr-keyword-expansion

Other features currently held back by Bazaars feature set:

Features held back by Subversion:

Releases

Debian/Ubuntu packages for 0.3.2 are available from http://samba.org/~jelmer/debian/. Ubuntu feisty already contains the latest release.

Requirements

The plugin requires a couple of fixes to the Python bindings for Subversion that are only available in Subversion 1.5 (trunk). Debian/Ubuntu packages with these fixes backported are available in Ubuntu Edgy & Feisty and Debian Sid & Etch. You need the [http://packages.ubuntu.com/edgy/python/python-subversion python-subversion] and [http://packages.ubuntu.com/edgy/libs/libsvn0 libsvn0] packages.

A patch against Subversion 1.4.3 is also available at http://samba.org/~metze/subversion-1.4.0-metze-python-bindings.patch. To build Subversions' Python bindings, run:

` $ tar xvfj subversion-1.4.3.tar.bz2 $ cd subversion-1.4.3 $ ./autogen.sh --release $ ./configure $ make $ make check-swig-py $ sudo make install install-swig-py `

If you are using Python 2.4, you will need to have the pysqlite module installed. Python 2.5 and higher have sqlite support built in.

After ensuring these dependencies are met, you should be able to check out branches from Subversion using regular bzr commands.

An older patch for Subversion 1.3.2 is available [http://people.samba.org/bzr/jelmer/subversion-1.3.2-pythonfixes.diff here]

Installation instructions for Fedora/Redhat are on https://planning.acm.org/hq/documentation/version-control/installing-bzr-svn

Installation instructions for Gentoo are on http://blogger.malept.com/2007/03/awn-bzr-branch-bazaar-overlay.html

Bugs

Please file bug reports in launchpad. The product URL for bzr-svn is https://launchpad.net/bzr-svn/.

Development

Branches

Unit testing

Simply run 'bzr selftest svn'

Credits

bzr-svn was written by JelmerVernooij with the help from various other people. See the AUTHORS file in the tarball for a list.