hacking cvs2svn ;)

Several months ago my BOSS asked me to transfer our ancient CVS repository to the brand new Subversion system. Not a big deal -I thought - there is lovely tool which does it for me: cvs2svn converter made by Tigris. But just after that I realized it wouldn't be such easy task, as our current repository is rather huge and holds several years of our projects history. Some fraction of packages was obsolete and additionally there was a request to split it to three different SVN repos and keep in a newly Subversion repos only recent year of history.

Not a big deal once again - I said after reading of cvs2svn documentation - we've got a database holding all the cvs tags used to built our software, so I'd make a few queries to know what to keep and that's all, except... OMG! There is no "include" pattern for tags!!!

You could in a easy way exclude symbols from cvs, which shouldn't be converted, but I've got completely opposite situation. Now, smart guys, please try to write me a reqexp which is nagative to a pattern... Oups!

What I did it was a little modification of cvs2svn tool in cvs2svn/cvs2svn_lib/symbol_strategy.py:

	class IncludeRegexpStrategyRule(StrategyRule):
	"""Include symbols matching pattern."""
	def __init__(self, pattern):
	try:
	self.regexp = re.compile('^' + pattern + '$')
	except re.error:
	raise FatalError("%r is not a valid regexp." % (pattern,))
	def log(self, symbol):
	Log().verbose(
	'Excluding symbol %s because it doesn\'t match regexp "%s".'
	% (symbol, self.regexp.pattern,)
	)
	def get_symbol(self, symbol, stats):
	if ( hasattr( symbol, "name" ) ):
	if self.regexp.match( symbol.name ):
	return symbol
	else:
	self.log( symbol )
	return ExcludedSymbol(symbol)
	else:
	return symbol

view raw cvs2svn.py hosted with ❤ by GitHub

Then of course I wrote a script which:

• asked our tag db for packages and their tags/branches that should be migrated
  
• generated cvs2svn option file
  
• and run cvs2svn tool
  

Several testing later a big migration day arrived on agenda. I've started to migrate about 9:00 AM and before 6:00 PM ca. 2k packages were moved generating initially about 190k revisions. And one day later we've opened new repos to the whole collaboration.