Is it possible to auto_link CAS accounts to pre-existing local ones?

Hi,

I have a gitlab installation on which all my users already have accounts. I want to move to SSO with CAS.

I can use CAS to login if there’s no local account with the same email. However, if there’s already an account with this email, I just can’t login and I get redirected to

/users/auth/cas3/omniauth_error?error=Email+has+already+been+taken

I have seen that for SAML, it can match and link users by email, but there’s no such option for CAS in the documentation. Do you have an idea how I could migrate ? I can change the CAS configuration if needed as I manage it too.

Thanks,

Jerome