Fatal error when wp_login_url is called from admin backend

Hello,

When anything (plugin or theme) requests wp_login_url or similar function from the admin backend (ie, when is_admin() == true) the it generates a fatal error. Here is a stack trace:

[30-May-2014 21:13:31 UTC] PHP Fatal error:  Call to a member function get_page_permastruct() on a non-object in D:\iPanelThemes\wordpress\wp-includes\link-template.php on line 356

[30-May-2014 21:13:31 UTC] PHP Stack trace:

[30-May-2014 21:13:31 UTC] PHP   1. {main}() D:\iPanelThemes\wordpress\wp-admin\admin-ajax.php:0

[30-May-2014 21:13:31 UTC] PHP   2. require_once() D:\iPanelThemes\wordpress\wp-admin\admin-ajax.php:20

[30-May-2014 21:13:31 UTC] PHP   3. require_once() D:\iPanelThemes\wordpress\wp-load.php:29

[30-May-2014 21:13:31 UTC] PHP   4. require_once() D:\iPanelThemes\wordpress\wp-config.php:110

[30-May-2014 21:13:31 UTC] PHP   5. do_action() D:\iPanelThemes\wordpress\wp-settings.php:236

[30-May-2014 21:13:31 UTC] PHP   6. call_user_func_array() D:\iPanelThemes\wordpress\wp-includes\plugin.php:470

[30-May-2014 21:13:31 UTC] PHP   7. IPT_FSQM_Loader->init_admin_menus() D:\iPanelThemes\wordpress\wp-includes\plugin.php:470

[30-May-2014 21:13:31 UTC] PHP   8. IPT_FSQM_All_Forms->__construct() D:\iPanelThemes\wordpress\wp-content\plugins\wp-fsqm-pro\classes\class-ipt-fsqm-loader.php:144

[30-May-2014 21:13:31 UTC] PHP   9. IPT_FSQM_Form_Elements_Admin->__construct() D:\iPanelThemes\wordpress\wp-content\plugins\wp-fsqm-pro\classes\class-ipt-fsqm-admin.php:603

[30-May-2014 21:13:31 UTC] PHP  10. IPT_FSQM_Form_Elements_Base->__construct() D:\iPanelThemes\wordpress\wp-content\plugins\wp-fsqm-pro\classes\class-ipt-fsqm-form-elements-admin.php:28

[30-May-2014 21:13:31 UTC] PHP  11. IPT_FSQM_Form_Elements_Base->init() D:\iPanelThemes\wordpress\wp-content\plugins\wp-fsqm-pro\classes\class-ipt-fsqm-form-elements-base.php:57

[30-May-2014 21:13:31 UTC] PHP  12. IPT_FSQM_Form_Elements_Base->get_default_settings() D:\iPanelThemes\wordpress\wp-content\plugins\wp-fsqm-pro\classes\class-ipt-fsqm-form-elements-base.php:70

[30-May-2014 21:13:31 UTC] PHP  13. wp_login_url() D:\iPanelThemes\wordpress\wp-content\plugins\wp-fsqm-pro\classes\class-ipt-fsqm-form-elements-base.php:1159

[30-May-2014 21:13:31 UTC] PHP  14. site_url() D:\iPanelThemes\wordpress\wp-includes\general-template.php:350

[30-May-2014 21:13:31 UTC] PHP  15. get_site_url() D:\iPanelThemes\wordpress\wp-includes\link-template.php:2482

[30-May-2014 21:13:31 UTC] PHP  16. apply_filters() D:\iPanelThemes\wordpress\wp-includes\link-template.php:2524

[30-May-2014 21:13:31 UTC] PHP  17. call_user_func_array() D:\iPanelThemes\wordpress\wp-includes\plugin.php:192

[30-May-2014 21:13:31 UTC] PHP  18. Theme_My_Login->site_url() D:\iPanelThemes\wordpress\wp-includes\plugin.php:192

[30-May-2014 21:13:31 UTC] PHP  19. Theme_My_Login::get_page_link() D:\iPanelThemes\wordpress\wp-content\plugins\theme-my-login\includes\class-theme-my-login.php:581

[30-May-2014 21:13:31 UTC] PHP  20. get_permalink() D:\iPanelThemes\wordpress\wp-content\plugins\theme-my-login\includes\class-theme-my-login.php:809

[30-May-2014 21:13:31 UTC] PHP  21. get_page_link() D:\iPanelThemes\wordpress\wp-includes\link-template.php:139

[30-May-2014 21:13:31 UTC] PHP  22. _get_page_link() D:\iPanelThemes\wordpress\wp-includes\link-template.php:322

As you can see it originated from a plugin calling wp_login_url() which in return got filtered by site_url and thereby calling a tml function which in return calls get_permalink() -> get_page_link() -> _get_page_link(). I did a little investigation and found that during the time when _get_page_link() was called, $wp_rewrite was completely empty (null). So that is causing the problem. I am yet to find the source of this conflict, but an solution is to apply all tml filters only on frontend. Under class Theme_My_Login::load() I added a conditional statement

if ( ! is_admin() ) :
add_filter( 'site_url',               array( &$this, 'site_url'               ), 10, 3 );
add_filter( 'logout_url',             array( &$this, 'logout_url'             ), 10, 2 );
add_filter( 'single_post_title',      array( &$this, 'single_post_title'      )        );
add_filter( 'the_title',              array( &$this, 'the_title'              ), 10, 2 );
add_filter( 'wp_setup_nav_menu_item', array( &$this, 'wp_setup_nav_menu_item' )        );
add_filter( 'wp_list_pages_excludes', array( &$this, 'wp_list_pages_excludes' )        );
add_filter( 'page_link',              array( &$this, 'page_link'              ), 10, 2 );
endif;

and it solved (ugly hack). Could you please look into this?

https://wordpress.org/plugins/theme-my-login/