convert: add a mode where mercurial_sink skips empty revisions. The getchanges function of some converter_source classes can return some false positives. I.e. they sometimes claim that a file "foo" was changed in some revision, even though its contents are still the same. convert_svn is particularly bad, but I think this can also happen with convert_cvs and, at least in theory, with mercurial_source. For regular conversions this is not really a problem - as long as getfile returns the right contents, we'll get a converted revision with the right contents. But when we use --filemap, this could lead to superfluous revisions being converted. Instead of fixing every converter_source, I decided to change mercurial_sink to work around this problem. When --filemap is used, we're interested only in revisions that touch some specific files. If a revision doesn't change any of these files, then we're not interested in it (at least for revisions with a single parent; merges are special). For mercurial_sink, we abuse this property and rollback a commit if the manifest text hasn't changed. This avoids duplicating the logic from localrepo.filecommit to detect unchanged files.

#!/usr/bin/env python
#
# Wrapper script around the convert.py hgext extension
# for foreign SCM conversion to mercurial format.
#

import sys
from mercurial import ui, fancyopts
from hgext import convert

# Options extracted from the cmdtable
func, options, help = convert.cmdtable['convert']

# An ui instance
u = ui.ui()

opts = {}
args = []
try:
    args = fancyopts.fancyopts(sys.argv[1:], options, opts)
except fancyopts.getopt.GetoptError, inst:
    u.warn('Usage:\n%s' % help)
    sys.exit(-1)

convert._convert(u, *args, **opts)