Using deepcopy() caused a major performance regression. Turns
out we can work with a shallow copy as long as we force the
recreation of any list that we change, effectively a poor mans
CoW. This isn't too invasive and avoids the huge overhead of
deepcopy so this seems like the best way to have performance and
a working data store.
(Bitbake rev: 32dff4749c32f32e947c42c86f8357b8b607354b)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
19f290f223