Hide attributes which match no products when option filtering is enabled on a component of a composite product

woo-composite-products-disable-empty-filters.php

<?php
/*
When you enable the Options Filtering option in a component, a field shows up where you can select some product attributes.
The selected attributes and their terms are shown on the front-end to be used as filters.

Composite Products does not perform any checks to make sure that at least one product exists for each term. 
This is because enforcing these checks would have a significant performance impact on the page.
Use this snippet to automatically remove any terms that do not have any matching products.
*/
add_filter( 'woocommerce_composite_component_filters', 'sw_cp_disable_empty_filters', 10, 3 );

function sw_cp_disable_empty_filters ( $filters, $component_id, $composite ) {
	foreach ( $filters as $key => $value ) {
		if ( 'Color' == $value[ 'filter_name' ] ) {
			unset( $filters[ $key ][ 'filter_options' ][26] );
		}
	}
	return $filters;
}