Ensure a 'has_children' parameter is given to start_el

[jaapjanfrans]

In the current display_element function of the Walker class, a 'has_children' argument is only added if args[0] is an array.

I'm not quite sure why this is the case. Wouldn't it be easier if a has_children argument is always added and passed on on to the callback functions like start_el?

i've currently modified a custom walker to do it like this:

		//display this element
		if ( is_array( $args[0] ) )
			$args[0]['has_children'] = ! empty( $children_elements[$element->$id_field] );
		$cb_args = array_merge( array(&$output, $element, $depth), $args);
		$cb_args['has_children'] = ! empty( $children_elements[$element->$id_field] );

But recon it can be done in a cleaner way.

Could you please point to the file and line number where has_children is set?

sure!

file '/wp-includes/classes.php' on line number 854

First of all, call_user_func_array() only accepts a numeric array, so $cb_argshas_children? wouldn't work.

Secondly, it checks if $args[0] is an array so that start_el() can be both:

start_el($arg1 = 'foo', $arg2 = 'bar', ...)

and

start_el($args = array())

Anyway, it's just a convenience. You can do the check yourself, since you have access to $children_elements.

I see your point, but it would still be nice if the start_el function could get this argument passed on by default, because now it only knows of this argument if the $args object passed to display_element is an array.. or am I missing something something there? I mean, $children_elements is not available to start_el in some way is it?

for now I resorted to adding the has_children argument to the $args object if it is an object (in display_element):

		//display this element
		if ( is_array( $args[0] ) )
			$args[0]['has_children'] = ! empty( $children_elements[$element->$id_field] );
		else
			$args[0]->has_children = ! empty( $children_elements[$element->$id_field] );
		
		$cb_args = array_merge( array(&$output, $element, $depth), $args);

Set flag on Walker object

You're right, start_el() doesn't have access to $children_elements.

Instead of altering $cb_args, a better solution would be to set a flag on the Walker object instead. See has_children.diff

You could then do:

function start_el() {
  if ( $this->has_children ) {
    // etc.
  }
}

Nice, thanks!

Related: #14102