diff-index: careful when inspecting work tree items

Earlier, if you changed a staged path into a directory in the work tree,
we happily ran lstat(2) on it and found that it exists, and declared that
the user changed it to a gitlink.

This is wrong for two reasons:

 (1) It may be a directory, but it may not be a submodule, and in the
     latter case, the change we need to report is "the blob at the path
     has disappeared".  We need to check with resolve_gitlink_ref() to be
     consistent with what "git add" and "git update-index --add" does.

 (2) lstat(2) may have succeeded only because a leading component of the
     path was turned into a symbolic link that points at something that
     exists in the work tree.  In such a case, the path itself does not
     exist anymore, as far as the index is concerned.

This fixes these breakages in diff-index that the previous patch has
exposed.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/t/t2201-add-update-typechange.sh b/t/t2201-add-update-typechange.sh
index 75c440c74..469a8e073 100755
--- a/t/t2201-add-update-typechange.sh
+++ b/t/t2201-add-update-typechange.sh
@@ -109,7 +109,7 @@ test_expect_failure diff-files '
 	diff -u expect-files actual
 '
 
-test_expect_failure diff-index '
+test_expect_success diff-index '
 	git diff-index --raw HEAD -- >actual &&
 	diff -u expect-index actual
 '