Allow terms to match the order in the include parameter

[glebkema]

Fix #66

To fix the problem it's necessary to change the behavior of the plugin in two aspects.

1) scporder_get_terms_orderby()

This method is used with the filter get_terms_orderby and changes the $orderby on t.term_order.

$orderby = 't.term_order';
return $orderby;

To fix this, it's enough to add one more check:

if (isset($args['include']) && isset($args['orderby']) && 'include' === $args['orderby'])
	return $orderby;

2) scporder_get_object_terms()

This method is used with two filters get_terms and wp_get_object_terms and sorts the found terms by the term_order.

usort($terms, array($this, 'taxcmp'));
return $terms;

This situation is more complicated. To check the include option in an array of arguments, we need to pass the $args parameter to the function.

if (isset($args['include']) && isset($args['orderby']) && 'include' === $args['orderby'])
	return $terms;

But this parameter is located at different positions in the mentioned hooks:

apply_filters( 'get_terms', $terms, $taxonomies, $args, $term_query );
apply_filters( 'wp_get_object_terms', $terms, $object_ids, $taxonomies, $args );

In this regard, I propose to add an auxiliary method. Its role is to invoke a neighboring method with another set of arguments:

public function scporder_get_object_terms($terms, $object_ids, $taxonomies, $args) {
    return $this->scporder_get_terms($terms, $taxonomies, $args);
}

public function scporder_get_terms($terms, $taxonomies, $args) {

And use a specific function for each hook:

add_filter('wp_get_object_terms', array($this, 'scporder_get_object_terms'), 10, 4);
add_filter('get_terms', array($this, 'scporder_get_terms'), 10, 3);