Also! I ended up pulling in jasig/phpCAS via composer so I had to tweak this line:
$CASAuth["phpCAS"]="$IP/vendor/jasig/phpcas";

I'll put that in as a comment at least~

@jpgill86 could you also enable Issues maybe? (at https://github.com/CWRUChielLab/CASAuth/settings )
I wanted to start a thread about making this a composer package :)

Hello @caseywatts,

Since we use this repository for our internal systems, I will need to verify that these changes don't break anything in our environment before merging your pull request. I don't expect that I will have time to check this soon--hopefully in August!

Jeff

I can confirm, this pull request works for me with MediaWiki 1.35 LTS.
I must correct myself, the logout does not work, as described in #13.

It should be fixed like this:

// Store the session name and id in a new logout ticket session to be able
// to find it again when single signing-out
function casPostAuth($ticket2logout) {

        // remember the current session name and id
        $session = MediaWiki\Session\SessionManager::getGlobalSession();
        // $old_session_name=$session->getName();
        $old_session_id=$session->getId();

Problem: there is no getName in https://github.com/wikimedia/mediawiki/blob/master/includes/session/Session.php#L48

it works for me with

        $session = MediaWiki\Session\SessionManager::getGlobalSession();
        $session->clear();
        return;

But that does not work with a new logout ticket session, I don't know what single signing-out means and is.

And I need to reload the page, otherwise I still get the error described in #13.