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.

#!/bin/sh

"$TESTDIR/hghave" svn svn-bindings || exit 80

fix_path()
{
    tr '\\' /
}

echo "[extensions]" >> $HGRCPATH
echo "convert = " >> $HGRCPATH

svnadmin create svn-repo

echo % initial svn import
mkdir t
cd t
echo a > a
cd ..

svnpath=`pwd | fix_path`
# SVN wants all paths to start with a slash. Unfortunately,
# Windows ones don't. Handle that.
expr $svnpath : "\/" > /dev/null
if [ $? -ne 0 ]; then
    svnpath='/'$svnpath
fi

svnurl=file://$svnpath/svn-repo/trunk
svn import -m init t $svnurl | fix_path

echo % update svn repository
svn co $svnurl t2 | fix_path
cd t2
echo b >> a
echo b > b
svn add b
svn ci -m changea
cd ..

echo % convert to hg once
hg convert $svnurl

echo % update svn repository again
cd t2
echo c >> a
echo c >> b
svn ci -m changeb
cd ..

echo % test incremental conversion
hg convert $svnurl