Re: Two issues with mark_reachable_objects

> I think we'd just want to run the whole mark_recent block after doing
> the bitmap traversal.
> 
> There may be some subtlety with reusing the rev_info struct again. I
> think we'd want to reset the pending objects list after calling into the
> bitmap code. It _usually_ does an actual traversal that consumes the
> list, but not necessarily. I think traverse_bitmap_commit_list()
> probably ought to be the one to do it, so it behaves more like
> traverse_commit_list(). (OTOH, I don't think it's _too_ bad if we don't;
> we'd include those already-seen objects in our traversal, but they
> should all by definition have the SEEN bit set, so we'd stop there).

> It's possible that we could do the second mark_recent traversal also
> with bitmaps (but still separately). I can't offhand think of a reason
> that ignore_missing_links wouldn't behave well there. But since we
> expect it to be small, I'd be more comfortable just using the regular
> traversal code.