Question

I have already used this hook in the same way described below, What could be going wrong?

class my_plugin {

    function __construct()
    {
        parent::__construct();

        var_dump(__LINE__); // run 
        add_filter('login_redirect', array($this, 'login_redirect'));
    }

    function login_redirect()
    {
        var_dump(__LINE__); // not run
    }

}

EDIT 1

This hook run after successfully login processes. As I said I have used this hook in another plugins. The question is What could cause this malfunction?

Answer 1

Ok, got it.

For the record:

It is sure that could helps someone else. Indeed time ago I suffered a problem triggered by the same reason: is_admin() incorrect use:

My starter code is:

if (is_admin())
{
    // block 1
    // 
    // run admin classes
    // including my_plugin class
    // that includes login_redirect hook // WRONG!
}
else
{
    // block 2
    // 
    // run frontend classes
}

login_redirect hook does not run inside admin pages (is_admin() condition)

Solution: move login_redirect hook to frontend block