current-menu-item and current_page_item classes incorrectly added to custom menu items with no URL value.

[tschoonover]

If the current page is the home page, the _wp_menu_item_classes_by_context function will incorrectly add the current-menu-item and current_page_item classes to any custom menu items that do not have a value for URL. This occurs because the custom menu item URL (after formatting) compares equal to the home page URL.

Note - a custom menu item might not have a URL value if it is used as only a parent container for another submenu.

[duck_]

Caused by [18746] for #15954 because $_root_relative_current is an empty string for the home page. We could check if the URL is empty for custom menu items before adding classes.

[nacin]

Attached patch prevents an empty URL from triggering the current-menu-item class.

It also allows a relative root URL ("/") to trigger the current-menu-item class, as before.

[nacin]

In [19657]:

Properly handle a blank nav menu custom URL when determining what page we're on. see #19699 for trunk.

[ryan]

In [19658]:

Properly handle a blank nav menu custom URL when determining what page we're on. fixes #19699 for 3.3