Make PasswordToken cloneable

[roj1512]

No description provided.

[Lonami]

Why is this change needed?

[roj1512]

So I can retry check_password() with the PasswordToken from SignInError::PasswordRequired when I get SignInError::PasswordInvalid.

[Lonami]

Good point. I would prefer if another solution was chosen, though, as making cloneable defeats the purpose of "making invalid states irrepresentable" (here, being able to use the token freely, even after successful sign-in).

What we should do is change the return type of check_password so that it includes the token every time. Then you can reuse the token if and only if the method failed and you're not logged in.

But I know that's a pain.

So please at least add:

// TODO this should not be Clone, but check_password Err doesn't include it back yet

above the change so we can remember to address it in the future. And then we can merge this temporary workaround.

(Unless you want to implement the better Err. That's the better solution.)

[roj1512]

check_password Err doesn't include it back yet

check_password error or SignInError::PasswordInvalid?

[Lonami]

The Error type used in check_password's Err variant should probably be a new enum specific to that method.

We probably want something as discussed in https://t.me/gramme_rs/17454. But that can come later. I'm happy with adding the TODO for now.

[roj1512]

Done!