menu_page_url not returning correct URL for custom submenus

[williamsba1]

When using the menu_page_url() function to determine the URL to a submenu of a custom top-level menu it's not returning the correct URL.

The function returns:
​http://example.com/wp-admin/cpt_main_menu?page=cpt_sub_add_new

The correct URL is:
​http://example.com/wp-admin/admin.php?page=cpt_sub_add_new

For reference my submenu is registered like so:

add_submenu_page('cpt_main_menu', 'Add New', 'Add New', 'administrator', 'cpt_sub_add_new', 'cpt_add_new');

I tested this on the custom top level menu and the URL returned is correct. It only appears to be an issue with submenus of a custom top level menu

[duck_]

If the menu item's parent is unset then it's a submenu of a builtin menu otherwise it also has an admin.php URL.

Was also thinking of trying to get menu_page_url to work for the predefined menu slugs (e.g. tools.php)

Updated unit-tests at ​#UT10

[nacin]

(In [16829]) Fix menu_page_url() for submenu pages attached to custom menu pages. props duck_, see #14159.

[nacin]

Was also thinking of trying to get menu_page_url to work for the predefined menu slugs (e.g. tools.php)

Future?

[nacin]

Sorry for the noise.

[chriscct7]

Doesn't appear to be anything left to fix per the original ticket. If there's still interest in comment:3, that could be split off into a new ticket and pursued.