OpenSSL follows the convention that whenever you call a function, it returns an error indicator value; and if this value is negative, then you need to go look at the actual error code to see what happened. Commit c6fd1c1 introduced a small mistake in _ssl__SSLSocket_shutdown_impl: instead of checking whether the error indicator was negative, it started checking whether the actual error code was negative, and it turns out that the error codes are never negative. So the effect was that 'unwrap()' lost the ability to raise SSL errors. https://bugs.python.org/issue34759. (cherry picked from commit c0da582) Co-authored-by: Nathaniel J. Smith <njs@pobox.com> https://bugs.python.org/issue34759