Code review comment for lp:~gagern/bzr/bug869912-log-root-dir

We can't really merge this as it is given the performance impact, but I would like there to be a way to do this.

One cheap way would be to just add an option that says to follow the previous history of the root.

Perhaps there is a better way to detect it. Making log filtered by ids faster would be well worth while too, but it's unlikely to ever have zero cost.

I'm going to bump this out of the review queue for now but please do ask if you want to talk more about how to solve it.