Remove WordPress class to method filter from third party plugin `remove_class_filter`

remove_class_filter.php

<?php
// Found on https://wpforthewin.com/remove-hook-from-class-based-wp-plugin/

/**
 * Make sure the function does not exist before defining it
 */
if (!function_exists('remove_class_filter')) {
    /**
     * Remove Class Filter Without Access to Class Object
     *
     * In order to use the core WordPress remove_filter() on a filter added with the callback
     * to a class, you either have to have access to that class object, or it has to be a call
     * to a static method.  This method allows you to remove filters with a callback to a class
     * you don't have access to.
     *
     * Works with WordPress 1.2+ (4.7+ support added 9-19-2016)
     * Updated 2-27-2017 to use internal WordPress removal for 4.7+ (to prevent PHP warnings output)
     *
     * @param string $tag Filter to remove
     * @param string $class_name Class name for the filter's callback
     * @param string $method_name Method name for the filter's callback
     * @param int $priority Priority of the filter (default 10)
     *
     * @return bool Whether the function is removed.
     */
    function remove_class_filter($tag, $class_name = '', $method_name = '', $priority = 10) {
        global $wp_filter;
        // Check that filter actually exists first
        if (!isset($wp_filter[$tag])) {
            return false;
        }
        /**
         * If filter config is an object, means we're using WordPress 4.7+ and the config is no longer
         * a simple array, rather it is an object that implements the ArrayAccess interface.
         *
         * To be backwards compatible, we set $callbacks equal to the correct array as a reference (so $wp_filter is updated)
         *
         * @see https://make.wordpress.org/core/2016/09/08/wp_hook-next-generation-actions-and-filters/
         */
        if (is_object($wp_filter[$tag]) && isset($wp_filter[$tag]->callbacks)) {
            // Create $fob object from filter tag, to use below
            $fob = $wp_filter[$tag];
            $callbacks = &$wp_filter[$tag]->callbacks;
        }
        else {
            $callbacks = &$wp_filter[$tag];
        }
        // Exit if there aren't any callbacks for specified priority
        if (!isset($callbacks[$priority]) || empty($callbacks[$priority])) {
            return false;
        }
        // Loop through each filter for the specified priority, looking for our class & method
        foreach ((array)$callbacks[$priority] as $filter_id => $filter) {
            // Filter should always be an array - array( $this, 'method' ), if not goto next
            if (!isset($filter['function']) || !is_array($filter['function'])) {
                continue;
            }
            // If first value in array is not an object, it can't be a class
            if (!is_object($filter['function'][0])) {
                continue;
            }
            // Method doesn't match the one we're looking for, goto next
            if ($filter['function'][1] !== $method_name) {
                continue;
            }
            // Method matched, now let's check the Class
            if (get_class($filter['function'][0]) === $class_name) {
                // WordPress 4.7+ use core remove_filter() since we found the class object
                if (isset($fob)) {
                    // Handles removing filter, reseting callback priority keys mid-iteration, etc.
                    $fob->remove_filter($tag, $filter['function'], $priority);
                }
                else {
                    // Use legacy removal process (pre 4.7)
                    unset($callbacks[$priority][$filter_id]);
                    // and if it was the only filter in that priority, unset that priority
                    if (empty($callbacks[$priority])) {
                        unset($callbacks[$priority]);
                    }
                    // and if the only filter for that tag, set the tag to an empty array
                    if (empty($callbacks)) {
                        $callbacks = array();
                    }
                    // Remove this filter from merged_filters, which specifies if filters have been sorted
                    unset($GLOBALS['merged_filters'][$tag]);
                }

                return true;
            }
        }

        return false;
    }
}