Composite Products disallow component purchases

add_filter( 'woocommerce_is_purchasable', function( $is_purchasable, $product ) {

	// Allow Single Product Pages
	if( is_product() ) {
		return $is_purchasable;
	}

	// Proceed Only If Product Has Component Term
	if( ! has_term( 'component-only', 'product_tag', $product->get_id() ) ) {
		return $is_purchasable;
	}

	// Allow Woo Component Parent To Add To Cart
	if( isset( $_POST['wccp_component_selection'] ) ) {
		return true;
	}

	// Allow Viewing Cart And Checkout After Adding Component
	foreach( WC()->cart->get_cart() as $item ) {
		if( isset( $item['composite_data'] ) ) {
			return true;
		}
	}

	// Default Fail
	return false;

}, 10, 2 );