is_user_logged_in() isn't working

Question

I'm making a login form for my site, and I've this section:

<?php
if (is_user_logged_in()) {
    echo 'Hello, ', $user_login, '. <a href="', wp_logout_url(), '" title="Logout">Logout</a>';
} else {
    wp_login_form();
}

And after loggin in, it returns to the page with no indication of logging in.
I suspect is_user_logged_in() isn't working, but I don't know how to debug this problem.

EDIT: Whenever I do this:

global $current_user;
var_dump($current_user);

I always get:

ect(WP_User)#3 (7) { ["data"]=> NULL ["ID"]=> int(0) ["caps"]=> array(0) { } ["cap_key"]=> NULL ["roles"]=> array(0) { } ["allcaps"]=> array(0) { } ["filter"]=> NULL }

No matter if i've 'logged' in with the above form.

Answer 1

There's nothing wrong with the function, it's the fact that you aren't actually being logged in!

You say you're making your own login form? Does this post to the standard wp-login.php, or do you handle the request yourself?

Does the path/domain of the form differ from WordPress? If you inspect your cookies, are any being set?

Answer 2

I know it is pretty late, but I am adding my answer to help others. If you use wp_signon() function to login, and verify with is_user_logged_in() thereafter, you need to set the current user with wp_set_current_user() first because wp_signon() does not handle setting the current user as described in the WP codex:

https://developer.wordpress.org/reference/functions/wp_signon/

This is one of the reasons why the function is_user_logged_in() says false when you thought you have logged in a user already.