Qouting myself here from IRC in case anyone missed this. I've already lost a couple of working copies due to this problem, so just in case this helps someone I'm pasting it here:
<stsp> when this happens with the bump-to-19.py script: "skipped: format is 16 not 18:" <stsp> you have basically lost your working copy <stsp> I see no way to recover from that state <stsp> svn upgrade won't do anything to it <stsp> nor will the script <stsp> because svn upgrade complains that the subdirectories aren't working copy roots <stsp> so it won't go to format 18 <stsp> any ideas? <stsp> the only way to avoid this I can see is as follows: <stsp> for item in `find . -type dir | grep -v \.svn`; do svn status $item; done <stsp> that will run status on all directories in the working copy, bumping them to 18 in the process <stsp> if you don't call status on each dir, it will error out too early, leaving some dirs at older formats (like 16) <stsp> then the bump-to-19.py script works
