@giampaolo.rodola thanks for insight on tests. I dint catch that at all :)

I am working on tests for os.renames() I opened an issue to track that here : https://bugs.python.org/issue35982.

IMHO, I think we need to improve the current behavior.

This discussion is not yet conclusive. You pointed out that this fix makes the problem a lot less likely to occur but we may end up with a race condition.

Can we close this PR so that maybe someone comes with a fix that addresses both problems? can we work with this fix? Am happy to comply with any decision. cc @vstinner

Once we agree on this, I will make necessary changes also in the review of this PR.