Altaf Hussain Patel on "[Plugin: Taxonomy Metadata] PHP fatal error on WP update to 4.4"

<?php
/*
Plugin Name: Taxonomy Metadata
Description: Infrastructure plugin which implements metadata functionality for taxonomy terms, including for tags and categories.
Version: 0.4
Author: mitcho (Michael Yoshitaka Erlewine), sirzooro
Author URI: http://mitcho.com/
*/

class Taxonomy_Metadata {
function __construct() {
add_action( 'init', array($this, 'wpdbfix') );
add_action( 'switch_blog', array($this, 'wpdbfix') );
add_action('wpmu_new_blog', array($this, 'new_blog'), 10, 6);
}

/*
* Quick touchup to wpdb
*/
function wpdbfix() {
global $wpdb;
$wpdb->taxonomymeta = "{$wpdb->prefix}taxonomymeta";
}

/*
* TABLE MANAGEMENT
*/

function activate( $network_wide = false ) {
global $wpdb;

// if activated on a particular blog, just set it up there.
if ( !$network_wide ) {
$this->setup_blog();
return;
}

$blogs = $wpdb->get_col( "SELECT blog_id FROM {$wpdb->blogs} WHERE site_id = '{$wpdb->siteid}'" );
foreach ( $blogs as $blog_id ) {
$this->setup_blog( $blog_id );
}
// I feel dirty... this line smells like perl.
do {} while ( restore_current_blog() );
}

function setup_blog( $id = false ) {
global $wpdb;

if ( $id !== false)
switch_to_blog( $id );

$charset_collate = '';
if ( ! empty($wpdb->charset) )
$charset_collate = "DEFAULT CHARACTER SET $wpdb->charset";
if ( ! empty($wpdb->collate) )
$charset_collate .= " COLLATE $wpdb->collate";
$tables = $wpdb->get_results("show tables like '{$wpdb->prefix}taxonomymeta'");
if (!count($tables)) {
$wpdb->query("CREATE TABLE {$wpdb->prefix}taxonomymeta (
meta_id bigint(20) unsigned NOT NULL auto_increment,
taxonomy_id bigint(20) unsigned NOT NULL default '0',
meta_key varchar(255) default NULL,
meta_value longtext,
PRIMARY KEY (meta_id),
KEY taxonomy_id (taxonomy_id),
KEY meta_key (meta_key)
) $charset_collate;");
}
}

function new_blog( $blog_id, $user_id, $domain, $path, $site_id, $meta ) {
if ( is_plugin_active_for_network(plugin_basename(__FILE__)) )
$this->setup_blog($blog_id);
}
}
$taxonomy_metadata = new Taxonomy_Metadata;
//register_activation_hook( __FILE__, array($taxonomy_metadata, 'activate') );

add_action('init', array($taxonomy_metadata, 'activate'));

// THE REST OF THIS CODE IS FROM http://core.trac.wordpress.org/ticket/10142
// BY sirzooro

//
// Taxonomy meta functions
//

/**
* Add meta data field to a term.
*
* @param int $term_id Post ID.
* @param string $key Metadata name.
* @param mixed $value Metadata value.
* @param bool $unique Optional, default is false. Whether the same key should not be added.
* @return bool False for failure. True for success.
*/

function add_term_meta($term_id, $meta_key, $meta_value, $unique = false) {
return add_metadata('taxonomy', $term_id, $meta_key, $meta_value, $unique);
}

/**
* Remove metadata matching criteria from a term.
*
* You can match based on the key, or key and value. Removing based on key and
* value, will keep from removing duplicate metadata with the same key. It also
* allows removing all metadata matching key, if needed.
*
* @param int $term_id term ID
* @param string $meta_key Metadata name.
* @param mixed $meta_value Optional. Metadata value.
* @return bool False for failure. True for success.
*/

function delete_term_meta($term_id, $meta_key, $meta_value = '') {
return delete_metadata('taxonomy', $term_id, $meta_key, $meta_value);
}

/**
* Retrieve term meta field for a term.
*
* @param int $term_id Term ID.
* @param string $key The meta key to retrieve.
* @param bool $single Whether to return a single value.
* @return mixed Will be an array if $single is false. Will be value of meta data field if $single
* is true.
*/
//modified by twoclock.com
if(!function_exists('get_term_meta')){
// my_function is defined
function get_term_meta($term_id, $key, $single = false) {
return get_metadata('taxonomy', $term_id, $key, $single);
}
}
//modified by twoclock.com

/**
* Update term meta field based on term ID.
*
* Use the $prev_value parameter to differentiate between meta fields with the
* same key and term ID.
*
* If the meta field for the term does not exist, it will be added.
*
* @param int $term_id Term ID.
* @param string $key Metadata key.
* @param mixed $value Metadata value.
* @param mixed $prev_value Optional. Previous value to check before removing.
* @return bool False on failure, true if success.
*/
function update_term_meta($term_id, $meta_key, $meta_value, $prev_value = '') {
return update_metadata('taxonomy', $term_id, $meta_key, $meta_value, $prev_value);
}