2.5.0
 *
 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
 *
 * @param WP_Term|int|string $term     The term object, ID, or slug whose link will be retrieved.
 * @param string             $taxonomy Optional. Taxonomy. Default empty.
 * @return string|WP_Error URL of the taxonomy term archive on success, WP_Error if term does not exist.
 */
function get_term_link( $term, $taxonomy = '' ) {
	global $wp_rewrite;

	if ( ! is_object( $term ) ) {
		if ( is_int( $term ) ) {
			$term = get_term( $term, $taxonomy );
		} else {
			$term = get_term_by( 'slug', $term, $taxonomy );
		}
	}

	if ( ! is_object( $term ) ) {
		$term = new WP_Error( 'invalid_term', __( 'Empty Term.' ) );
	}

	if ( is_wp_error( $term ) ) {
		return $term;
	}

	$taxonomy = $term->taxonomy;

	$termlink = $wp_rewrite->get_extra_permastruct( $taxonomy );

	/**
	 * Filters the permalink structure for a terms before token replacement occurs.
	 *
	 * @since 4.9.0
	 *
	 * @param string  $termlink The permalink structure for the term's taxonomy.
	 * @param WP_Term $term     The term object.
	 */
	$termlink = apply_filters( 'pre_term_link', $termlink, $term );

	$slug = $term->slug;
	$t    = get_taxonomy( $taxonomy );

	if ( empty( $termlink ) ) {
		if ( 'category' === $taxonomy ) {
			$termlink = '?cat=' . $term->term_id;
		} elseif ( $t->query_var ) {
			$termlink = "?$t->query_var=$slug";
		} else {
			$termlink = "?taxonomy=$taxonomy&term=$slug";
		}
		$termlink = home_url( $termlink );
	} else {
		if ( $t->rewrite['hierarchical'] ) {
			$hierarchical_slugs = array();
			$ancestors          = get_ancestors( $term->term_id, $taxonomy, 'taxonomy' );
			foreach ( (array) $ancestors as $ancestor ) {
				$ancestor_term        = get_term( $ancestor, $taxonomy );
				$hierarchical_slugs[] = $ancestor_term->slug;
			}
			$hierarchical_slugs   = array_reverse( $hierarchical_slugs );
			$hierarchical_slugs[] = $slug;
			$termlink             = str_replace( "%$taxonomy%", implode( '/', $hierarchical_slugs ), $termlink );
		} else {
			$termlink = str_replace( "%$taxonomy%", $slug, $termlink );
		}
		$termlink = home_url( user_trailingslashit( $termlink, 'category' ) );
	}

	// Back compat filters.
	if ( 'post_tag' === $taxonomy ) {

		/**
		 * Filters the tag link.
		 *
		 * @since 2.3.0
		 * @since 2.5.0 Deprecated in favor of {@see 'term_link'} filter.
		 * @since 5.4.1 Restored (un-deprecated).
		 *
		 * @param string $termlink Tag link URL.
		 * @param int    $term_id  Term ID.
		 */
		$termlink = apply_filters( 'tag_link', $termlink, $term->term_id );
	} elseif ( 'category' === $taxonomy ) {

		/**
		 * Filters the category link.
		 *
		 * @since 1.5.0
		 * @since 2.5.0 Deprecated in favor of {@see 'term_link'} filter.
		 * @since 5.4.1 Restored (un-deprecated).
		 *
		 * @param string $termlink Category link URL.
		 * @param int    $term_id  Term ID.
		 */
		$termlink = apply_filters( 'category_link', $termlink, $term->term_id );
	}

	/**
	 * Filters the term link.
	 *
	 * @since 2.5.0
	 *
	 * @param string  $termlink Term link URL.
	 * @param WP_Term $term     Term object.
	 * @param string  $taxonomy Taxonomy slug.
	 */
	return apply_filters( 'term_link', $termlink, $term, $taxonomy );
}

/**
 * Display the taxonomies of a post with available options.
 *
 * This function can be used within the loop to display the taxonomies for a
 * post without specifying the Post ID. You can also use it outside the Loop to
 * display the taxonomies for a specific post.
 *
 * @since 2.5.0
 *
 * @param array $args {
 *     Arguments about which post to use and how to format the output. Shares all of the arguments
 *     supported by get_the_taxonomies(), in addition to the following.
 *
 *     @type  int|WP_Post $post   Post ID or object to get taxonomies of. Default current post.
 *     @type  string      $before Displays before the taxonomies. Default empty string.
 *     @type  string      $sep    Separates each taxonomy. Default is a space.
 *     @type  string      $after  Displays after the taxonomies. Default empty string.
 * }
 */
function the_taxonomies( $args = array() ) {
	$defaults = array(
		'post'   => 0,
		'before' => '',
		'sep'    => ' ',
		'after'  => '',
	);

	$parsed_args = wp_parse_args( $args, $defaults );

	echo $parsed_args['before'] . implode( $parsed_args['sep'], get_the_taxonomies( $parsed_args['post'], $parsed_args ) ) . $parsed_args['after'];
}

/**
 * Retrieve all taxonomies associated with a post.
 *
 * This function can be used within the loop. It will also return an array of
 * the taxonomies with links to the taxonomy and name.
 *
 * @since 2.5.0
 *
 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
 * @param array       $args {
 *           Optional. Arguments about how to format the list of taxonomies. Default empty array.
 *
 *     @type string $template      Template for displaying a taxonomy label and list of terms.
 *                                 Default is "Label: Terms."
 *     @type string $term_template Template for displaying a single term in the list. Default is the term name
 *                                 linked to its archive.
 * }
 * @return array List of taxonomies.
 */
function get_the_taxonomies( $post = 0, $args = array() ) {
	$post = get_post( $post );

	$args = wp_parse_args(
		$args,
		array(
			/* translators: %s: Taxonomy label, %l: List of terms formatted as per $term_template. */
			'template'      => __( '%s: %l.' ),
			'term_template' => '<a href="%1$s">%2$s</a>',
		)
	);

	$taxonomies = array();

	if ( ! $post ) {
		return $taxonomies;
	}

	foreach ( get_object_taxonomies( $post ) as $taxonomy ) {
		$t = (array) get_taxonomy( $taxonomy );
		if ( empty( $t['label'] ) ) {
			$t['label'] = $taxonomy;
		}
		if ( empty( $t['args'] ) ) {
			$t['args'] = array();
		}
		if ( empty( $t['template'] ) ) {
			$t['template'] = $args['template'];
		}
		if ( empty( $t['term_template'] ) ) {
			$t['term_template'] = $args['term_template'];
		}

		$terms = get_object_term_cache( $post->ID, $taxonomy );
		if ( false === $terms ) {
			$terms = wp_get_object_terms( $post->ID, $taxonomy, $t['args'] );
		}
		$links = array();

		foreach ( $terms as $term ) {
			$links[] = wp_sprintf( $t['term_template'], esc_attr( get_term_link( $term ) ), $term->name );
		}
		if ( $links ) {
			$taxonomies[ $taxonomy ] = wp_sprintf( $t['template'], $t['label'], $links, $terms );
		}
	}
	return $taxonomies;
}

/**
 * Retrieve all taxonomy names for the given post.
 *
 * @since 2.5.0
 *
 * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
 * @return string[] An array of all taxonomy names for the given post.
 */
function get_post_taxonomies( $post = 0 ) {
	$post = get_post( $post );

	return get_object_taxonomies( $post );
}

/**
 * Determine if the given object is associated with any of the given terms.
 *
 * The given terms are checked against the object's terms' term_ids, names and slugs.
 * Terms given as integers will only be checked against the object's terms' term_ids.
 * If no terms are given, determines if object is associated with any terms in the given taxonomy.
 *
 * @since 2.7.0
 *
 * @param int                       $object_id ID of the object (post ID, link ID, ...).
 * @param string                    $taxonomy  Single taxonomy name.
 * @param int|string|int[]|string[] $terms     Optional. Term ID, name, slug, or array of such
 *                                             to check against. Default null.
 * @return bool|WP_Error WP_Error on input error.
 */
function is_object_in_term( $object_id, $taxonomy, $terms = null ) {
	$object_id = (int) $object_id;
	if ( ! $object_id ) {
		return new WP_Error( 'invalid_object', __( 'Invalid object ID.' ) );
	}

	$object_terms = get_object_term_cache( $object_id, $taxonomy );
	if ( false === $object_terms ) {
		$object_terms = wp_get_object_terms( $object_id, $taxonomy, array( 'update_term_meta_cache' => false ) );
		if ( is_wp_error( $object_terms ) ) {
			return $object_terms;
		}

		wp_cache_set( $object_id, wp_list_pluck( $object_terms, 'term_id' ), "{$taxonomy}_relationships" );
	}

	if ( is_wp_error( $object_terms ) ) {
		return $object_terms;
	}
	if ( empty( $object_terms ) ) {
		return false;
	}
	if ( empty( $terms ) ) {
		return ( ! empty( $object_terms ) );
	}

	$terms = (array) $terms;

	$ints = array_filter( $terms, 'is_int' );
	if ( $ints ) {
		$strs = array_diff( $terms, $ints );
	} else {
		$strs =& $terms;
	}

	foreach ( $object_terms as $object_term ) {
		// If term is an int, check against term_ids only.
		if ( $ints && in_array( $object_term->term_id, $ints, true ) ) {
			return true;
		}

		if ( $strs ) {
			// Only check numeric strings against term_id, to avoid false matches due to type juggling.
			$numeric_strs = array_map( 'intval', array_filter( $strs, 'is_numeric' ) );
			if ( in_array( $object_term->term_id, $numeric_strs, true ) ) {
				return true;
			}

			if ( in_array( $object_term->name, $strs, true ) ) {
				return true;
			}
			if ( in_array( $object_term->slug, $strs, true ) ) {
				return true;
			}
		}
	}

	return false;
}

/**
 * Determine if the given object type is associated with the given taxonomy.
 *
 * @since 3.0.0
 *
 * @param string $object_type Object type string.
 * @param string $taxonomy    Single taxonomy name.
 * @return bool True if object is associated with the taxonomy, otherwise false.
 */
function is_object_in_taxonomy( $object_type, $taxonomy ) {
	$taxonomies = get_object_taxonomies( $object_type );
	if ( empty( $taxonomies ) ) {
		return false;
	}
	return in_array( $taxonomy, $taxonomies, true );
}

/**
 * Get an array of ancestor IDs for a given object.
 *
 * @since 3.1.0
 * @since 4.1.0 Introduced the `$resource_type` argument.
 *
 * @param int    $object_id     Optional. The ID of the object. Default 0.
 * @param string $object_type   Optional. The type of object for which we'll be retrieving
 *                              ancestors. Accepts a post type or a taxonomy name. Default empty.
 * @param string $resource_type Optional. Type of resource $object_type is. Accepts 'post_type'
 *                              or 'taxonomy'. Default empty.
 * @return int[] An array of IDs of ancestors from lowest to highest in the hierarchy.
 */
function get_ancestors( $object_id = 0, $object_type = '', $resource_type = '' ) {
	$object_id = (int) $object_id;

	$ancestors = array();

	if ( empty( $object_id ) ) {

		/** This filter is documented in wp-includes/taxonomy.php */
		return apply_filters( 'get_ancestors', $ancestors, $object_id, $object_type, $resource_type );
	}

	if ( ! $resource_type ) {
		if ( is_taxonomy_hierarchical( $object_type ) ) {
			$resource_type = 'taxonomy';
		} elseif ( post_type_exists( $object_type ) ) {
			$resource_type = 'post_type';
		}
	}

	if ( 'taxonomy' === $resource_type ) {
		$term = get_term( $object_id, $object_type );
		while ( ! is_wp_error( $term ) && ! empty( $term->parent ) && ! in_array( $term->parent, $ancestors, true ) ) {
			$ancestors[] = (int) $term->parent;
			$term        = get_term( $term->parent, $object_type );
		}
	} elseif ( 'post_type' === $resource_type ) {
		$ancestors = get_post_ancestors( $object_id );
	}

	/**
	 * Filters a given object's ancestors.
	 *
	 * @since 3.1.0
	 * @since 4.1.1 Introduced the `$resource_type` parameter.
	 *
	 * @param int[]  $ancestors     An array of IDs of object ancestors.
	 * @param int    $object_id     Object ID.
	 * @param string $object_type   Type of object.
	 * @param string $resource_type Type of resource $object_type is.
	 */
	return apply_filters( 'get_ancestors', $ancestors, $object_id, $object_type, $resource_type );
}

/**
 * Returns the term's parent's term_ID.
 *
 * @since 3.1.0
 *
 * @param int    $term_id  Term ID.
 * @param string $taxonomy Taxonomy name.
 * @return int|false Parent term ID on success, false on failure.
 */
function wp_get_term_taxonomy_parent_id( $term_id, $taxonomy ) {
	$term = get_term( $term_id, $taxonomy );
	if ( ! $term || is_wp_error( $term ) ) {
		return false;
	}
	return (int) $term->parent;
}

/**
 * Checks the given subset of the term hierarchy for hierarchy loops.
 * Prevents loops from forming and breaks those that it finds.
 *
 * Attached to the {@see 'wp_update_term_parent'} filter.
 *
 * @since 3.1.0
 *
 * @param int    $parent   `term_id` of the parent for the term we're checking.
 * @param int    $term_id  The term we're checking.
 * @param string $taxonomy The taxonomy of the term we're checking.
 * @return int The new parent for the term.
 */
function wp_check_term_hierarchy_for_loops( $parent, $term_id, $taxonomy ) {
	// Nothing fancy here - bail.
	if ( ! $parent ) {
		return 0;
	}

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

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

	// Setting $parent 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;
}

/**
 * Determines whether a taxonomy is considered "viewable".
 *
 * @since 5.1.0
 *
 * @param string|WP_Taxonomy $taxonomy Taxonomy name or object.
 * @return bool Whether the taxonomy should be considered viewable.
 */
function is_taxonomy_viewable( $taxonomy ) {
	if ( is_scalar( $taxonomy ) ) {
		$taxonomy = get_taxonomy( $taxonomy );
		if ( ! $taxonomy ) {
			return false;
		}
	}

	return $taxonomy->publicly_queryable;
}

/**
 * Sets the last changed time for the 'terms' cache group.
 *
 * @since 5.0.0
 */
function wp_cache_set_terms_last_changed() {
	wp_cache_set( 'last_changed', microtime(), 'terms' );
}

/**
 * Aborts calls to term meta if it is not supported.
 *
 * @since 5.0.0
 *
 * @param mixed $check Skip-value for whether to proceed term meta function execution.
 * @return mixed Original value of $check, or false if term meta is not supported.
 */
function wp_check_term_meta_support_prefilter( $check ) {
	if ( get_option( 'db_version' ) < 34370 ) {
		return false;
	}

	return $check;
}