Sunday, April 06, 2008

Migrating from CVS to Subversion

I recently migrated the Task Coach source code from its Sourceforge CVS repository to a Subversion repository, also on Sourceforge. I followed the migration instructions at the Sourceforge website and all went smoothly.

Because the cvs2svn script needs the CVSROOT module present, you can only remove it after cvs2svn has run, i.e. you need remove it from the svndump file that cvs2svn creates. svndumpfilter does do that for you. Unfortunately, the CVSROOT module is present in the svndump file multiple times: not only in the trunk folder, but also in all branch and version folders of the svndump. A script to help with finding all those CVSROOT occurences would be nice.

Marcin ZajÄ…czkowski helped me out with a shell script. I used it as the basis for a little python script that removes specific folders or files from your svndump file. Use as you like.

#!/usr/bin/env python

import os, optparse

usage = '''Usage: %prog dumpfile path [path...]
Remove path(s) from <dumpfile> and write new dump file to <dumpfile>.out'''

class PathRemoverOptionParser(optparse.OptionParser):
def __init__(self):
optparse.OptionParser.__init__(self, usage)

def parse_args(self):
options, args = optparse.OptionParser.parse_args(self)
if len(args) < 2:
self.error('provide both dumpfile and path to remove')
dumpFile, paths = args[0], args[1:]
if not os.path.exists(dumpFile):
self.error('dumpfile (%s) does not exist'%dumpFile)
return dumpFile, paths

def branches(dumpFile, paths, pathPrefix='Node-path: '):
''' Find branches in the dumpFile that contain the paths. '''
for line in file(dumpFile):
if line.startswith(pathPrefix):
for path in paths:
if line.endswith(path+'\n'):
yield line[len(pathPrefix):-1] # yield branch

parser = PathRemoverOptionParser()
dumpFile, paths = parser.parse_args()
excludes = ' '.join(branches(dumpFile, paths))
if not excludes:
parser.error('path(s) (%s) not found'%', '.join(paths))

os.system('svndumpfilter exclude %s < %s > %s.out'%(excludes, dumpFile, dumpFile))