Jeff King [off-list ref] writes:
(I still think the concept of avoiding the revindex should
still work in principle, though).
Yes, absolutely. The streaming code cares only about non-delta, and in
general applying delta without holding the base image entirely in core
would be horribly complex unless the delta only runs forwards over the
delta-base image. The true general case is not something this topic is
interested in (it is primarily about the large objects), and limiting
ourselves to non-delta case is just as fine.