wp_check_term_hierarchy_for_loops() │ WP 3.1.0

Checks the given subset of the term hierarchy for hierarchy loops. Prevents loops from forming and breaks those that it finds.

Attached to the wp_update_term_parent filter.

No Hooks.

Returns

Int. The new parent for the term.

Usage

wp_check_term_hierarchy_for_loops( $parent_term, $term_id, $taxonomy );

$parent_term(int) (required)

term_id of the parent for the term we're checking.

$term_id(int) (required)

The term we're checking.

$taxonomy(string) (required)

The taxonomy of the term we're checking.

Changelog

wp_check_term_hierarchy_for_loops() wp check term hierarchy for loops code ^{WP 6.9.1}

function wp_check_term_hierarchy_for_loops( $parent_term, $term_id, $taxonomy ) {
	// Nothing fancy here - bail.
	if ( ! $parent_term ) {
		return 0;
	}

	// Can't be its own parent.
	if ( $parent_term === $term_id ) {
		return 0;
	}

	// Now look for larger loops.
	$loop = wp_find_hierarchy_loop( 'wp_get_term_taxonomy_parent_id', $term_id, $parent_term, array( $taxonomy ) );
	if ( ! $loop ) {
		return $parent_term; // No loop.
	}

	// Setting $parent_term to the given value causes a loop.
	if ( isset( $loop[ $term_id ] ) ) {
		return 0;
	}

	// There's a loop, but it doesn't contain $term_id. Break the loop.
	foreach ( array_keys( $loop ) as $loop_member ) {
		wp_update_term( $loop_member, $taxonomy, array( 'parent' => 0 ) );
	}

	return $parent_term;
}