False positives in git diff-index

[Alexander Gladysh <agladysh@gmail.com>]

Hi, list!

I wrote about the related issue earlier:

http://lists-archives.org/git/731516-false-positives-from-git-diff-index-when-used-with-git-dir.html

Now I've got a case when I can reproduce this problem each time I try to.

Unfortunately I can not share it or create a minimal example — the
case is triggered by a custom complicated automated build process on a
private repository.

Anyway, I'm ready to debug this issue if someone will guide me.

Workflow:

<...change files in /path/dir1/...>
(cd /path && git add </path/dir1/>)
(cd /path && git commit -m <message1>)

... repeat change-add-commit several times for various directories
(can be the same directory or not) ...

<...generate file /path/dirN/foo...>
# Accidentally the file is generated the same as it was

(cd /path && git add </path/dirN/>)
(cd /path && git status) # Refresh index
(cd /path && git diff-index --exit-code --quiet HEAD -- /path/dirN) #
Incorrectly reports that there are some changes
(cd /path && git commit -m <messageN>) # fails, saying that there is
nothing to commit

If I insert sleep 10 between git status and git diff-index, the
problem goes away.

Any help?
Alexander.