The cache-tree optimization originally helped speed up write-tree
operation. However, many commands no longer properly maintain -- or
use an opportunity to cheaply generate -- the cache-tree data. In
particular, this affects commit, checkout and reset. The notable
examples that *do* write cache-tree data are read-tree and write-tree.
This sadly means most people no longer benefit from the optimization,
as they would not normally use the plumbing commands.
Document the current state of affairs in a test file, in preparation
for improvements in the area.
Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>