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Differences between revisions 2 and 84 (spanning 82 versions)
Revision 2 as of 2006-03-06 12:30:46
Size: 506
Comment: Add comments about progress.
Revision 84 as of 2006-12-19 12:09:20
Size: 9241
Comment: import-svn is now svn-impot
Deletions are marked like this. Additions are marked like this.
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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 allows bzr direct access to Subversion repositories. This allows {{{bzr branch}}}, {{{bzr push}}}, {{{bzr pull}}}, and {{{bzr co}}} to work directly against Subversion repositories.
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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.
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This plugin needs a full rewrite after the large amount of changes in the bzr API before 0.8. It is fully functional, but has only been tested on a few different Subversion branches (samba, wireshark, subversion, cups), so should be considered alpha.
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This rewrite is currently in progress. = 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]
 * [http://samba.org/~jelmer/bzr/bzrsvn-samba3.png bzrk 3]
 * [http://samba.org/~jelmer/bzr/bzrsvn-samba3a.png bzrk 4]

= 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/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 http://svn.collab.net/repos/svn/trunk
 * [http://people.samba.org/bzr/jelmer/svn/1.3.x Subversion 1.3.x] - Original at http://svn.collab.net/repos/svn/branches/1.3.x
 * [http://people.samba.org/bzr/jelmer/svn/1.4.x Subversion 1.4.x] - Original at http://svn.collab.net/repos/svn/branches/1.4.x
 * [http://people.samba.org/bzr/jelmer/svn/lorikeet-trunk Lorikeet trunk] - Original at svn://svn.samba.org/lorikeet/trunk
 * [http://people.samba.org/bzr/jelmer/samba/build-farm-trunk/ Build Farm trunk] - Original at svn://svn.samba.org/build-farm/trunk
 * [http://people.samba.org/bzr/jelmer/pkg-samba/samba4/ Samba4 Debian package] - Original at svn+ssh://svn.debian.org/svn/pkg-samba/branches/samba4
 * [http://people.samba.org/bzr/jelmer/pkg-samba/sid/ Samba3 Sid Debian package] - Original at svn+ssh://svn.debian.org/svn/pkg-samba/branches/sid
 * [http://people.samba.org/bzr/jelmer/wireshark/trunk Wireshark] - Original at http://anonsvn.wireshark.org/wireshark/trunk
 * [http://people.samba.org/bzr/jelmer/samba-pdbsql/trunk Samba pdbsql] - Original at https://svn.sourceforge.net/svnroot/pdbsql/trunk/samba-pdbsql
 * [http://people.samba.org/bzr/jelmer/cups/trunk CUPS Trunk] - Original at http://svn.easysw.com/public/cups/trunk
 * [http://people.samba.org/bzr/jelmer/cups/branches/kerberos CUPS Kerberos] - Original at http://svn.easysw.com/public/cups/branches/kerberos

= 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).

 * '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. 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 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.

== 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

 * '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'. 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:

 * 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.
  . Spec at https://launchpad.net/products/bzr/+spec/shallow-checkouts

 * 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

= Releases =

 * [http://samba.org/~jelmer/bzr/bzr-svn-0.2.tar.gz 0.2] (works with Bazaar 0.13 and higher)
 * [http://samba.org/~jelmer/bzr/bzr-svn-0.1.tar.gz 0.1] (works with Bazaar 0.8 and higher)

= 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. 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 1.3.2 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
}}}

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

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

= Development =

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

== Unit testing ==
Simply run 'bzr selftest svn'

TableOfContents(2)

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.

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.

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).
  • '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
  • "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 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.

Properties

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:

Features held back by Subversion:

Releases

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. 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 1.3.2 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

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

Bugs

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

Development

Branches

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

Unit testing

Simply run 'bzr selftest svn'