Code review comment for lp:~ian-clatworthy/bzr/filtering-revert-bug

(after irc discussion)

What I'm referring to with the comment about globals is the way the tests save and restore WorkingTree._content_filter_stack. They're relying on the way that class variables underlie instance variables, which (while it works) has been shown to be fragile or confusing.

However, this isn't new code in this patch so I won't insist it be fixed here. I do think it would be good to add a comment since we've talked about it.

Thanks.