Work has begun to support OpenID Connect, which enables one to use any OAuth 2.0 identity solution. It is planned for Mattermost Cloud and Mattermost Self-Managed E20.
An error occurred while saving the commentAnonymous commented
It seems that two other requests that would be covered by having this feature - Microsoft ADFS  and Phabricator OAuth2 
A PR was been submitted  and concerns of maintainability and testing  were raised. As the existing gitlab code can be removed in favour of the generic OAuth2, the maintenance and testing should be comparative if not identical.
The community can also help with the testing, if the MM team can tell us of the procedure and reporting they'd like to see.
It seems perfectly reasonable, right?