Resolve#1551 and #1020.
We are never returning the result of solved operations so Buildkit could not
cache the layer.
This commit implements a simple system to forward operations' result to the
main build to cache it.
Signed-off-by: Vasek - Tom C <tom.chauveau@epitech.eu>
Because of the mount disjunction, passing a non-concrete #FS results in
CUE being confused as to what type of mount it is (Cache, FS, Secret,
...).
This adds an explicit error check.
Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>
