Bazaar

Bazaar

 




Wiki Tools

  • Find Page
  • Recent Changes
  • Page History
  • Attachments

Differences between revisions 1 and 67 (spanning 66 versions)
Revision 1 as of 2005-11-22 01:48:01
Size: 789
Comment: Add page about support for foreign Subversion branches.
Revision 67 as of 2006-07-20 21:25:46
Size: 7785
Comment: Add links to example branches.
Deletions are marked like this. Additions are marked like this.
Line 1: Line 1:
http://samba.org/~jelmer/bzr/svn/ contains the beginnings a plugin for bzr that adds support for foreign Subversion repositories. Running 'bzr log' on a remote repository works now, as well as various other simple things, such as ["bzrk"] ([http://samba.org/~jelmer/bzrk-svn.png screenshot]). [[TableOfContents(2)]]
= Introduction =
This plugin provides a mapping between Bazaar and Subversion revisions unambiguous so to people that run Bazaar on a Subversion branch end up with exactly the same branch and can pull changes from each other.
Line 3: Line 5:
In order to run this plugin, you need support for BzrForeignBranches. 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.
Line 5: Line 7:
== TODO == It is fully functional, but has only been tested on a few different Subversion branches (samba, wireshark, subversion, cups), so should be considered alpha.
Line 7: Line 9:
 * Finish SvnRevisionTree so data can be viewed correctly
 * Implement fetch/pull (needs to be fixed in core first)
 * Finish LocalSvnBranch. uuid_from_path currently segfaults. SvnWorkingTree needs to be finished
= Screenshots =
 * [http://samba.org/~jelmer/bzrk-svn.png bzrk 1]
 * [http://samba.org/~jelmer/bzr/bzrsvn-merge.png bzrk 2]
 * [http://samba.org/~jelmer/bzr/bzrsvn-renames.png renames]
 * [http://samba.org/~jelmer/bzr/bzrsvn-commit.png commits]
 * [http://samba.org/~jelmer/bzr/bzr-push-to-svn.png push]
 * [http://samba.org/~jelmer/bzr/bzr-push-samba.png push 2]
Line 11: Line 17:
 * Generate Inventories from Revisions rather then the other way around (as is default in bzr). This should increase speed a lot. 'svn ls' is used at the moment, and is very, very slow. = Example branches =
All created by simply running {{bzr branch ORIGINAL-URL}}. * [http://people.samba.org/bzr/jelmer/samba/3.0 Samba 3] - Original at svn://svn.samba.org/samba/branches/SAMBA_3_0[http://people.samba.org/bzr/jelmer/samba/3.0 ]
 * [http://people.samba.org/bzr/jelmer/samba/4.0 Samba 4] - Original at svn://svn.samba.org/samba/branches/SAMBA_4_0
 * [http://people.samba.org/bzr/jelmer/samba/docs Samba docs] - Original at svn://svn.samba.org/samba-docs/trunk
 * [http://people.samba.org/bzr/jelmer/svn/trunk Subversion trunk] - Original at svn+http://svn.collab.net/repos/svn

= 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 vanilla working copied 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).

 * 'import-svn' 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:

 * 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. Those brave enough can test the current support out by registering SvnRenamingRepository instead of SvnRepository in __init__.py.

 * "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.

 * Proper read locking, which has basically been ignored for now.

 * Proper Windows support. Most of the code depends on '/' being the path separator at the moment.

 * 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 disk space and CPUs

  * 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.

 * Creating native Subversion working copies. This would mostly be supported for completeness' sake, there are not a lot of advantages in supporting it.

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.

 * 'svn:externals'. Externals should be mapped to Bazaar 'by-reference' nested branches and the other way around. This can't be implemented until Bazaars nested branch support lands. AaronBentley's work in progress is at http://code.aaronbentley.com/bzr/bzrrepo/nested-trees/. Has been delayed until after 0.9 because of required repository format changes. https://launchpad.net/products/bzr/+spec/nested-tree-support

 * 'svn:mime-type'

 * 'svn:eol-style'

 * '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:

 * Horizon revision history. Most of the existing Subversion repositories are quite large and it would therefore be nice to be able to limit the amount of history that needs to be retrieved during checkouts. Subversion supports horizon history fine.

 * Tracking copies.
  . Spec at https://launchpad.net/products/bzr/+spec/filecopies

Features held back by Subversion:

 * Showing SVN merges as merges in Bazaar. This requires full merge information in Subversion, something which the Subversion folks are working on at the moment (see https://svn.collab.net/repos/svn/branches/merge-tracking). However, this seems to require support for cherry-picking. See https://launchpad.net/products/bzr/+spec/bzr-cpick-data

= Implementation =
http://people.samba.org/bzr/jelmer/bzr-svn/bzr.dev

= Installation =
The plugin requires a couple of fixes to the Python bindings for Subversion. Debian/Ubuntu packages available at http://samba.org/~jelmer/bzr/. You need the python-subversion and libsvn0 packages. These changes have been submitted to the Ubuntu Subversion package in [https://launchpad.net/products/bzr-svn/+bug/51304 #51304].

A patch against Subversion 1.3.2 is also available at http://people.samba.org/bzr/jelmer/subversion-1.3.2-pythonfixes.diff. To build Subversions' Python bindings, run:

{{{
$ tar xvfj subversion-1.3.2.tar.bz2
$ cd subversion-1.3.2
$ ./autogen.sh --release
$ ./configure
$ make
$ make check-swig-py
$ sudo make install install-swig-py
}}}

You will also need bzr.dev plus the fixes from the following branches if you would like to use lightweight checkouts:

 * http://people.samba.org/bzr/jelmer/bzr/revision-tree-fixes

Simply place this directory in ~/.bazaar/plugins and you should be able to check out branches from Subversion using bzr.

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

= License =
GNU General Public License, v2 or later.

= Unit testing =
Simply run 'bzr selftest svn'

TableOfContents(2)

Introduction

This plugin provides a mapping between Bazaar and Subversion revisions unambiguous so to people that run Bazaar on a Subversion branch end up with exactly the same branch and can pull changes from each other.

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.

It is fully functional, but has only been tested on a few different Subversion branches (samba, wireshark, subversion, cups), so should be considered alpha.

Screenshots

Example branches

All created by simply running bzr branch ORIGINAL-URL. * [http://people.samba.org/bzr/jelmer/samba/3.0 Samba 3] - Original at svn://svn.samba.org/samba/branches/SAMBA_3_0[http://people.samba.org/bzr/jelmer/samba/3.0 ]

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 vanilla working copied 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).
  • 'import-svn' 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:

  • Renames. Initial work has been done to support this, but the number of corner cases is wide, so support for this
  • "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.
  • Proper read locking, which has basically been ignored for now.
  • Proper Windows support. Most of the code depends on '/' being the path separator at the moment.
  • 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 disk space and CPUs
    • 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.
  • Creating native Subversion working copies. This would mostly be supported for completeness' sake, there are not a lot of advantages in supporting it.

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

Other features currently held back by Bazaars feature set:

  • Horizon revision history. Most of the existing Subversion repositories are quite large and it would therefore be nice to be able to limit the amount of history that needs to be retrieved during checkouts. Subversion supports horizon history fine.
  • Tracking copies.

Features held back by Subversion:

Implementation

http://people.samba.org/bzr/jelmer/bzr-svn/bzr.dev

Installation

The plugin requires a couple of fixes to the Python bindings for Subversion. Debian/Ubuntu packages available at http://samba.org/~jelmer/bzr/. You need the python-subversion and libsvn0 packages. These changes have been submitted to the Ubuntu Subversion package in [https://launchpad.net/products/bzr-svn/+bug/51304 #51304].

A patch against Subversion 1.3.2 is also available at http://people.samba.org/bzr/jelmer/subversion-1.3.2-pythonfixes.diff. To build Subversions' Python bindings, run:

$ tar xvfj subversion-1.3.2.tar.bz2
$ cd subversion-1.3.2
$ ./autogen.sh --release
$ ./configure
$ make
$ make check-swig-py
$ sudo make install install-swig-py

You will also need bzr.dev plus the fixes from the following branches if you would like to use lightweight checkouts:

Simply place this directory in ~/.bazaar/plugins and you should be able to check out branches from Subversion using bzr.

Bugs

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

License

GNU General Public License, v2 or later.

Unit testing

Simply run 'bzr selftest svn'