The WordPress Categories to Tags Converter.

The "Categories to Tags Converter Importer" seems to work like a charm in WordPress 6.1 and lower. I've only added a couple of fixes for PHP >7, and missing history. See also: https://github.com/WordPress/wpcat2tag-importer/pull/1

1. Tested with WordPress 6.1
2. Tested with PHP 7.4.33

How to test:

1. Clone the plugin
2. Spin a new docker image[^1]
3. Substitute YOUR_FOLDER with the path of the cloned plugin
4. Go to http://localhost/wp-admin/plugins.php and activate Categories to Tags Converter Importer
5. Activate a theme that supports post format: http://localhost/wp-admin/theme-install.php (filter with: Features -> "Post Formats")
6. Create some tags, some categories, and some posts tagged with that
7. Open http://localhost/wp-admin/admin.php?import=wpcat2tag
8. Try to convert tags to categories, categories to tags and etc. The plugin must load correctly and no errors displayed

[^1]: docker-compose.yml file

services:
  db:
    image: mariadb:latest
    command: '--default-authentication-plugin=mysql_native_password'
    volumes:
      - db_data:/var/lib/mysql
    restart: always
    environment:
      - MYSQL_ROOT_PASSWORD=somewordpress
      - MYSQL_DATABASE=wordpress
      - MYSQL_USER=wordpress
      - MYSQL_PASSWORD=wordpress
    expose:
      - 3306
      - 33060
  wordpress:
    image: wordpress:latest
    volumes:
      - wp_data:/var/www/html
      - YOUR_FOLDER:/var/www/html/wp-content/plugins/wpcat2tag-importer
    ports:
      - 80:80
    restart: always
    environment:
      - WORDPRESS_DB_HOST=db
      - WORDPRESS_DB_USER=wordpress
      - WORDPRESS_DB_PASSWORD=wordpress
      - WORDPRESS_DB_NAME=wordpress
      - WORDPRESS_DEBUG=1
volumes:
  db_data:
  wp_data:

PHP 4-style constructors where the constructor function name mirrors the class name have been deprecated since PHP 7.0 and support has been removed since PHP 8.0, which means they are now silently ignored.

Considering the constructor is empty and is overloading an equally empty constructor in the WP_Importer class, I'm fixing this by removing the method.

This should not be considered a BC-break as calling the constructor directly on an instantiated object was never the intention of the code anyway and instantiating the object via new WP_Categories_to_Tags() will now fall through to the parent constructor, which equally does nothing anyway.

Refs:

• https://wiki.php.net/rfc/remove_php4_constructors