Comment 5 for bug 1551392

As far as I can see from keystoneauth code, this bug doesn't affect it as the functionality which contains this bug doesn't exist in keystoneauth at all.
DefaultCLI plugin in keystoneclient seems to be the only one able to handle both token and username/password auth at the same time. Comparing keystoneclient to keystoneauth, I would consider this to be a kind of "functional regression" as with keystoneauth clients need to add their own code to implement "fallback to username/password in case of invalid/expired token" functionality.
It seems that neither keystoneauth nor openstackclient provide any support for this kind of behavior.

As for not fixing this bug, I'm not sure how many projects are using keystoneclient but for sure there is muranoclient which still does. Without this fix the "fallback" functionality mentioned above will not work or will require more code on client side to implement something which could easily be fixed in keystoneclient.