Comment 2 for bug 764108

Additional points:

* Sergei's branch keys off the rule in the old tree, typically the committed tree. It seems to me it would normally be better to go off the new-side of the diff, which will more often be the working tree and which should make this easier to discover. However, since it doesn't read actually from either tree at the moment, it doesn't matter. So to actually use this you need something in ~/.bazaar/rules

* For this to be most useful, we'd need to also actually read the rules from the tree, which is apparently not done at the moment (though there is some infrastructure). (Which is bug 395731.)

* There's some risk a naive implementation of this will make diff slow even if no rules are configured, by scanning the rules file for every file that differs.