我刚刚进行了测试并弄清楚了.如果您没有为用户设置密码，则该用户将没有为他们设置任何登录方法(除了通过admin SDK创建自定义令牌并以此登录).

I just tested and figured it out. If you don't set a password for the user, the user will not have any sign in methods set for them (asside from creating a custom token from the admin SDK and signing in with that).

但是，如果您随后向该用户发送电子邮件登录链接，并且他们通过该链接登录，则会将无密码方法添加到他们的帐户中.

However if you then send an email sign-in link for the user, and they sign in through the link, it will add the passwordless method to their account.