Re: git status: small difference between stating whole repository and small subdirectory

Jeff King <peff@peff.net> writes:

Yes, but it depends on what kind of replaying you have in mind. It is very hard to come up with "replaying real-world test case".

For example, randomly picking commit pair <$A,$B> from the kernel repository and running

	git reset --hard $A
        git checkout $B
        T0=$(git write-tree)
        drop-cache-tree
        T1=$(git write-tree)
        test "$T0" = "$T1" && test "$T0" = $(git rev-parse $B^{tree})

is necessary but I do not think that is sufficient. We also want to do something like:

	git reset --hard $A
        ... modify paths that do not change between $A and $B
        ... git add these paths
        git write-tree
        git checkout $B

with and without the "git write-tree" to see the part of the cache-tree smudged by the modification behaves sanely. The codepath that is used to deal with the case where the index does not match $A but matches $B is also different, so the "modify path and git add" step would have to be crafted carefully to touch all bases.