git stash push/save/create all return exit code 0, even if no object was created

Hello there,

I am trying to run a `git checkout` command on a repository, without
the possibility of getting any error message about files interfering
with the checkout process.
I thought a safe way to do this was to run `git-stash`, similarly to
`rebase.autoStash = true`

However, I find two issues with those:
1) Exit code is 0, even if no object/stash was created.

It feels weird to parse stdout/stderr to decide "what happened".

2) `git stash create` (which sounds more like what I need), does not
clear what it was stored.
I can "take the pain" of printing the object-sha1 to be traceable if
something happens (even though I would prefer more if it was
"securely" stored in `refs/stash` i.e. `git stash push`), but then
`git stash` won't clean what it just stored.
Is the solution to also run `git reset --hard` there?

With regards,
Ntentos Stavros