[backend] Don't let the user use an alternative login method based on the same email

[pfortuna]

When a user logs in with e.g. Google and is using a specific email e.g. [email protected], if we previously had a registration using another login method with the same email, we should reject that registration and an error should be returned that asks the user to use the same login method he used before.

[pfortuna]

@geiras We need design of the error message /dialog.

[geiras]

Would be a possibility to remove the button of the wrong sign-in method after the warning message?

We already have design for error messages. Can we use the same, @pfortuna?

[pfortuna]

Would be a possibility to remove the button of the wrong sign-in method after the warning message?
Yes this is a possibility. And once we know, we also set a cookie to remember the correct login method. But sometimes we don't know that until we check the backend and return an error.

We already have design for error messages. Can we use the same, @pfortuna?
yes we can :-) can you post it here for facilitating?

[geiras]

I've designed new errors for this situation.

https://www.figma.com/file/BfK7HtPsvxZAwZLg1ebz2u/Covidografia?node-id=4007%3A7059
https://www.figma.com/file/BfK7HtPsvxZAwZLg1ebz2u/Covidografia?node-id=4007%3A7121

[pfortuna]

Perfect ! moving this to TODO!

[geiras]

This way the user can login with the correct method in the same popup where we show the error.