Custom Widget Creating PHP Exception When Placed In Its Own PHP File

Question

I have a custom plugin created and i have created a widget. At the moment this code is included in the base php file for the plugin and its working fine. I want to move the widget and all future ones into a widgets.php file and include them into the main plugin file. When i do this i get the following php error.

PHP Fatal error: Call to undefined function wp_get_current_user() in /var/www/wordpresstest/wp-includes/capabilities.php on line 1387

This is the code for the widget. This code works perfectly when i place it in the main plugin php file, but when i use require "widgets.php" i get the error.

<?php 
class nb_game_info_widget extends WP_Widget 
{
    function __construct() 
    {
        parent::__construct('nb_game_info_widget', __('Test Widget', 'nb_game_info_widget_domain'), array( 'description' => __( 'Game IDS Widget', 'nb_game_info_widget_domain' )));
    }

    public function widget( $args, $instance ) 
    {
        if(is_single())
        {
            $title = apply_filters( 'widget_title', $instance['title'] );
            echo $args['before_widget'];
            if ( ! empty( $title ) )
            echo $args['before_title'] . $title . $args['after_title'];

            global $post;
            $postid = $post->ID;

            $gameids = get_post_meta( $postid, 'nb_gameids_key', true );
            $platformids = get_post_meta( $postid, 'nb_platformids_key', true );
            echo "GAME IDS ! = ". $gameids;

            //required for the theme to do whatever it does
            echo $args['after_widget'];
        }
    }

    // Widget Backend 
    public function form( $instance ) {
        if ( isset( $instance[ 'title' ] ) ) 
        {
            $title = $instance[ 'title' ];
        }
        else {
            $title = __( 'New title', 'nb_game_info_widget_domain' );
        }
        // Widget admin form
        ?>
        <p>
        <label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label> 
        <input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>" />
        </p>
        <?php 
    }

    // Updating widget replacing old instances with new
    public function update( $new_instance, $old_instance ) 
    {
        $instance = array();
        $instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';
        return $instance;
    }
} // Class nb_game_info_widget ends here

// Register and load the widget
function nb_loag_gameinfo_widget() {
    register_widget( 'nb_game_info_widget' );
}
add_action( 'widgets_init', 'nb_loag_gameinfo_widget' );

Answer 1

I have no idea why this should solve the issue but I can solve it. Use a different file name. For example: include('my_widgets.php');

I get the error you describe with include('widgets.php'); but not with a different file name. I don't know why. I do know that WordPress has a Core file named widgets.php but I can't work out why there should be a conflict. It must have to do with the way that include crawls for files but I'd have to do some research-- get under the hood, so to speak. Moral of the story: Don't use generic file names :)