If test for "has_nav_menu()" does not return echo when no menu exists

Question

I have a strange issue with my if/else test for "has_nav_menu()" I have three menu locations in the template and each is tested if a menu exist in the defined location. However this example below does not echo the warning i want when and if a menu does not exist. The first test works fine, but this one does not. What am i missing ?

<!-- Secondary Navigation Area -->                  
        <div class="row">
            <div class="small-12 columns">
                <?php
                    if ( has_nav_menu( 'header-top' ) ) {
                        wp_nav_menu( array(
                            'theme_location'    => 'header-top',
                            'container'         => 'nav',
                            'menu_class'        => 'right no-bullets no-margin',                                        
                            'fallback_cb'       => false,                               
                        ));
                    } else {
                        /* echo Fallback code if no menu has been choosen from the dashboard */
                        echo '<p class="warning dark-bg">Her mangler det en meny.   Venligst gå tilbake til kontrollpanelet, <strong>Utseende > Menyer > Bestem plassering</strong> og velg en meny.</p>';
                    }
                ?>
            </div>
        </div>

Answer 1

If you check out has_nav_menu(), you'll see that it first checks if a menu exists for the location (what we expect).

However, it will also return true if the location is merely registered, hence why your condition is still true even when there's no menu:

function has_nav_menu( $location ) {
    $registered_nav_menus = get_registered_nav_menus();
    if ( ! isset( $registered_nav_menus[ $location ] ) ) {
        return false;
    }

    $locations = get_nav_menu_locations();
    return ( ! empty( $locations[ $location ] ) );
}

Instead, use the snippet from above to just check if an actual menu is registered:

$registered_nav_menus = get_registered_nav_menus();
if ( isset( $registered_nav_menus[ 'header-top' ] ) ) {
    // Your nav menu
} else {
    // No menu
}

Update: To check a valid menu exists & has items, use echo => false and check the output:

$menu = wp_nav_menu(
    array(
        'theme_location' => 'header-top',
        'container'      => 'nav',
        'menu_class'     => 'right no-bullets no-margin',
        'fallback_cb'    => false,
        'echo'           => false,
    )
);

if ( $menu ) {
    echo $menu;
} else {
    echo 'No menu!';
}