This page describes the FreeBSD Subversion to CVS exporter AKA svn2cvs.

The exporter runs on repoman.FreeBSD.org (mostly) in the directory /r/svn2cvs/.

Currently the page is work in progress and should not be relied on to be accurate!

svn2cvs overview

The basic purpose of the FreeBSD svn2cvs system is to replicate commits in the FreeBSD Subversion repository to the old CVS repository. svn2cvs preserves full commit information (as much as CVS allows) by exporting:

svn2cvs exporter basically works by examining each subversion commit and then replicating it as good as possible into CVS.

Due to the way CVS works $FreeBSD$ is changed by CVS so the original $FreeBSD$ set by Subversion is overwritten by CVS. To find out which Subversion revision a file in CVS is based on, one has to see the commit log which includes the revision ID.

svn2cvs parts

svn2cvs consists of the following parts:

Python 'export.py' script

TODO - Location (repo stored in, public access, etc...) and dependancies

Last exported revision property

The counter with the last exported revision is stored as a revision property stored on revision 0 and is called fbsd:lastexp. Note that the property is stored on the mirrored repository used by the exporter, not the main FreeBSD repository. The current value for /r/svnmirror/base can be retrieved using:

svn pg fbsd:lastexp --revprop -r 0 file:///r/svnmirror/base

maptable

TODO

Modified CVS

The modified version of CVS is changed from stock CVS as follows:

All the changes to the CVS repository is done with the modified cvs binary so there is no "magic" manipulation of the CVS repository.

Local FreeBSD svn mirror

TODO - setup, why needed, etc...

Create branch checklist

XXX This may _very_ well miss required steps!

How svn2cvs works, per commit

TODO

Caveats

Manual CVS work

If the CVS repository is every updated directly for whatever reason, the checkouts used by svn2cvs must also manually be updated. Otherwise, on the first export to the directory containing the manually modified files, the export will fail with an CVS up-to-date-check.

To recover from this situation, simply manually (as user svn2cvs) run cvs update in the affected directory, and revert the changes made for the export which fails. Now the exporter can be restarted.

Current problems

It doesn't like when a file is 'replaced' in Subversion.

As of this writing no files are out of sync.

Tips

The following command can be used to get all commits to a branch e.g. for hand exporting:

Simon's original suggestion:

svn2cvs (last edited 2012-09-18 09:02:54 by BjoernZeeb)