Nav Menu Roles

As of WordPress 5.4 the wp_nav_menu_item_custom_fields hook has been added to WordPress core.

Nav Menu Roles is therefore attaching directly to this hook without needing to replace the custom Admin Menu Walker, of which there can still be only one. If the Walker is replaced by a theme/plugin and the core hook is not included, then Nav Menu Roles cannot add it's fields.

A non-exhaustive list of known conflicts:

UberMenu 2.x Mega Menus plugin (UberMenu 3.x supports NMR!)
Add Descendants As Submenu Items plugin
Navception plugin
Suffusion theme
BeTheme
Yith Menu
Jupiter Theme
iMedica theme
Prostyler EVO theme
Mega Main Plugin

Workaround #1
Shazdeh had the genius idea to not wait for a core hook and simply add the hook ourselves. If all plugin and theme authors use the same hook, we can make our plugins play together.

Prior to WordPress 5.4, I used this idea and modified my admin nav menu Walker to only adding the following lines (right after the description input):

<?php
// Place this in your admin nav menu Walker
do_action( 'wp_nav_menu_item_custom_fields', $item_id, $item, $depth, $args, $id );
// end added section
?>

Since WordPress 5.4, I no longer replace the Walker at all and would advise other plugins and themes to do the same.

But for those that still are, they definitely need to include the now-core hook.

Ask your conflicting plugin/theme's author to add this code to their plugin or theme and our plugins will become compatible.
Instructions for Patching Your Plugin/Theme
Should you wish to attempt this patch yourself, you can modify your conflicting plugin/theme's admin menu Walker class.

Reminder: I do not provide support for fixing your plugin/theme. If you aren't comfortable with the following instructions, contact the developer of the conflicting plugin/theme!

1. Find the class that extends the Walker_Nav_Menu. The fastest way to do this is to search your whole plugin/theme folder for extends Walker_Nav_Menu. When you find the file that contains this text you will know which file you need to edit. Once you find it here's what the beginning of that class will look like:

class YOUR_THEME_CUSTOM_WALKER extends Walker_Nav_Menu {}

2. Find the start_el() method

In that file you will eventually see a class method that looks like:

function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
// some stuff truncated for brevity
}

3. Paste the action hook somewhere in this method!

In Nav Menu Roles, I have placed the hook directly after the description, like so:

<p class="field-description description description-wide">
<label for="edit-menu-item-description-<?php echo $item_id; ?>">
<?php _e( 'Description' ); ?><br />
<textarea id="edit-menu-item-description-<?php echo $item_id; ?>" class="widefat edit-menu-item-description" rows="3" cols="20" name="menu-item-description[<?php echo $item_id; ?>]"><?php echo esc_html( $item->description ); // textarea_escaped ?></textarea>
<span class="description"><?php _e('The description will be displayed in the menu if the current theme supports it.'); ?></span>
</label>
</p>

<?php
// Add this directly after the description paragraph in the start_el() method
do_action( 'wp_nav_menu_item_custom_fields', $item_id, $item, $depth, $args, $id );
// end added section
?>

Workaround #2
As a workaround, you can switch to a default theme (or disable the conflicting plugin), edit the Nav Menu Roles, for each menu item, then revert to your original theme/ re-enable the conflicting plugin. The front-end functionality of Nav Menu Roles will still work.
Workaround #3
Only works with WordPress less than 5.4.

Download and install this tiny plugin. Activate it when you need to make the NMR options appear and then disable it when you are done editing.
I'm using XYZ Membership plugin and I don't see its "levels"?
There are apparently a few membership plugins out there that don't use traditional WordPress roles/capabilities. My plugin will list any role registered in the traditional WordPress way. If your membership plugin is using some other system, then Nav Menu Roles won't work with it out of the box. Since 1.3.5 I've added a filter called nav_menu_roles_item_visibility just before my code decides whether to show/hide a menu item. There's also always been the nav_menu_roles filter which lets you modify the roles listed in the admin. Between these two, I believe you have enough to integrate Nav Menu Roles with any membership plugin.

Here's an example where I've added a new pseudo role, creatively called "new-role". The first function adds it to the menu item admin screen. The second function is pretty generic and won't actually do anything because you need to supply your own logic based on the plugin you are using. Nav Menu Roles will save the new "role" info and add it to the item in an array to the $item->roles variable.
Existing Compatibility Plugins

Wishlists Memberships
WooCommerce Memberships

If your membership plugin is not listed here, you may be able to use the above bridge plugins as a template. Scroll down to the bottom of the main plugin file and you will see a section for "Helper Functions". If you modify the 3 wrapper functions according to your membership plugin's logic, the rest of the plugin should handle the integration with Nav Menu Roles.
Adding a new "role"
The roles in NMR are filterable distinct from the global $wp_roles. This allows for compatibility to be added between plugins that don't use the core roles to determine access, like some membership plugins.

/**
* Add custom roles to Nav Menu Roles menu list
* param: $roles an array of all available roles, by default is global $wp_roles
* return: array
*/
function kia_new_roles( $roles ) {
$roles['new-role-key'] = 'new-role';
return $roles;
}
add_filter( 'nav_menu_roles', 'kia_new_roles' );

Note, if you want to add a WordPress capability the above is literally all you need. Because Nav Menu Roles checks whether a role has permission to view the menu item using current_user_can($role) you do not need to right a custom callback for thenav_menu_roles_item_visibility` filter.

In case you do need to check your visibility status against something very custom, here is how you'd go about it:

/**
* Change visibility of each menu item
* @param bool $visible
* @param obj $item The complete menu object. Nav Menu Roles adds its info to the following keys {
* roles - Possible value: "in" (all logged in) | "out" (all logged out) | an array of specific roles, ex: [ "administrator", "editor" ]
* display_mode - Possible values: "show" (show if conditions met) | "hide" (hide if conditions met)
* return boolean
*/
function kia_item_visibility( $visible, $item ) {
if ( isset( $item->roles ) && is_array( $item->roles ) && in_array( 'new-role-key', $item->roles ) ) {
/* if ( // your own custom check on the current user versus 'new-role' status ) {
$visible = true;
} else {
$visible = false;
}
*/ }
return $visible;
}
add_filter( 'nav_menu_roles_item_visibility', 'kia_item_visibility', 10, 2 );

Note that you have to generate your own if/then logic. I can't provide free support for custom integration with another plugin. You may contact me to discuss hiring me, or I would suggest using a plugin that supports WordPress' roles, such as Justin Tadlock's Members.
Sort the roles alphabetically
Add the following snippet to your theme's functions.php file:

/*
* Sort the NMR roles
* @param: $roles an array of all available roles with ID=>Name
* @return: array
*/
function kia_sort_roles( $roles ) {
if ( is_admin() ) {
$array_lowercase = array_map( 'strtolower', $roles );
array_multisort( $array_lowercase, SORT_ASC, SORT_STRING, $roles );
return $roles;
}
}
add_filter( 'nav_menu_roles', 'kia_sort_roles' );

The menu exploded? Why are all my pages displaying for logged out users?
If every item in your menu is configured to display to logged in users (either all logged in users, or by specific role), then when a logged out visitor comes to your site there are no items in the menu to display. wp_nav_menu() will then try check its fallback_cb argument... which defaults to wp_page_menu.

Therefore, if you have no items to display, WordPress will end up displaying ALL your pages!!

If you don't want this, you must set the fallback argument to be a null string.

wp_nav_menu( array( 'theme_location' => 'primary-menu', 'fallback_cb' => '' ) );

You must do this for every effected instance of wp_nav_menu() in your theme templates. It is not possible for me to tell you where they are located, but header.php is a very common location for the main menu.

Alternatively, you could do this universally by adding the following snippet to your child theme's function.php file or by adding it via the Code Snippets plugin:

/**
* Disables the fallback page menu for all menus
*
* @param array $args Array of wp_nav_menu() arguments.
* @return array
*/
function kia_nav_menu_args( $args ) {
$args['fallback_cb'] = '';
return $args;
}
add_filter( 'wp_nav_menu_args', 'kia_nav_menu_args' );

What happened to my menu roles on import/export?
The Nav Menu Roles plugin stores 1 piece of post meta to every menu item/post. This is exported just fine by the default Export tool.

Go to Tools>Export, choose to export All Content and download the Export file
Go to Tools>Import on your new site and perform your normal WordPress import
Return to Tools>Import and this time select the Nav Menu Roles importer.
Use the same .xml file and perform a second import
No duplicate posts will be created but all menu post meta (including your Nav Menu Roles info) will be imported

Is Nav Menu Roles compatible with WPML ?
Yes, but manually. WPML developers have informed me that the meta data for nav menu items is not synced by WPML, meaning that menus copied into a new language will not bring their custom Nav Menu Roles settings. However, if you manually reconfigure the settings, the new language menu will work as expected.