What is the purpose of auth.settings.login_userfield?

[Ray (a.k.a. Iceberg)]

Just want to double confirm.

1. I found many following lines in tools.py:

        userfield = self.settings.login_userfield or 'username' \
            if 'username' in table_user.fields else 'email'

it means:

        if 'username' in table_user.fields:
            userfield = self.settings.login_userfield or 'username'
        else:
            userfield = 'email


2. If we used a slightly different source code like this:

        userfield = self.settings.login_userfield or ('username'
            if 'username' in table_user.fields else 'email')

it means something quite different:

        if self.settings.login_userfield:  # if user explicitly define the login_userfield
            userfield = self.settings.login_userfield  # then use it unconditionally
        else:   # otherwise automatically determine one
            userfield = 'username' if 'username' in table_user.fields else 'email'


So, to double confirm, what is the design purpose of auth.settings.login_userfield? If it is #1, I recommend to use a pair of brackets to avoid misunderstanding.

        userfield = (self.settings.login_userfield or 'username'
            ) if 'username' in table_user.fields else 'email'

[Ray (a.k.a. Iceberg)]

Well, now I believe the #2 purpose is the design intention, based on this section in Auth.register():

        table_user = self.table_user()
        if self.settings.login_userfield:
            username = self.settings.login_userfield
        elif 'username' in table_user.fields:
            username = 'username'
        else:
            username = 'email'

In this case, I believe #1 is a bug and need to be fixed.

[Anthony]

Yes, seems like a bug. I guess no one uses this setting (probably because it's not documented).

Anthony