Notices when no items in nav menu

[mordauk]

When displaying a nav menu with wp_nav_menu() there are a lot of notices if the nav menu is created but has no nav items:

Some sample notices shown in the attached screenshot.

[mordauk]

Notices

[mordauk]

nav menu with no items

[SergeyBiryukov]

Could not reproduce on a clean install:

1. If there are no menu items, wp_nav_menu() falls back to wp_page_menu() by default:
   tags/3.6/wp-includes/nav-menu-template.php#L180​.
2. If I specify an empty fallback_cb parameter to disable the default fallback, then the walker is called via walk_nav_menu_tree(), but it bails out early if there are no items:
   tags/3.6/wp-includes/class-wp-walker.php#L182​.

Tested in both 3.6 and current trunk. Could you provide the exact steps to reproduce?

[nofearinc]

Can't reproduce here either, seems like the walker has been called on Pippin's setup and trying to work with empty $item being passed, but I can't replicate that use case either (by using the menu or theme_location arguments for wp_nav_menu).