diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-includes/widgets/class-wp-widget-categories.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/widgets/class-wp-widget-categories.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,182 @@
+<?php
+/**
+ * Widget API: WP_Widget_Categories class
+ *
+ * @package WordPress
+ * @subpackage Widgets
+ * @since 4.4.0
+ */
+
+/**
+ * Core class used to implement a Categories widget.
+ *
+ * @since 2.8.0
+ *
+ * @see WP_Widget
+ */
+class WP_Widget_Categories extends WP_Widget {
+
+	/**
+	 * Sets up a new Categories widget instance.
+	 *
+	 * @since 2.8.0
+	 */
+	public function __construct() {
+		$widget_ops = array(
+			'classname' => 'widget_categories',
+			'description' => __( 'A list or dropdown of categories.' ),
+			'customize_selective_refresh' => true,
+		);
+		parent::__construct( 'categories', __( 'Categories' ), $widget_ops );
+	}
+
+	/**
+	 * Outputs the content for the current Categories widget instance.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @staticvar bool $first_dropdown
+	 *
+	 * @param array $args     Display arguments including 'before_title', 'after_title',
+	 *                        'before_widget', and 'after_widget'.
+	 * @param array $instance Settings for the current Categories widget instance.
+	 */
+	public function widget( $args, $instance ) {
+		static $first_dropdown = true;
+
+		$title = ! empty( $instance['title'] ) ? $instance['title'] : __( 'Categories' );
+
+		/** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */
+		$title = apply_filters( 'widget_title', $title, $instance, $this->id_base );
+
+		$c = ! empty( $instance['count'] ) ? '1' : '0';
+		$h = ! empty( $instance['hierarchical'] ) ? '1' : '0';
+		$d = ! empty( $instance['dropdown'] ) ? '1' : '0';
+
+		echo $args['before_widget'];
+
+		if ( $title ) {
+			echo $args['before_title'] . $title . $args['after_title'];
+		}
+
+		$cat_args = array(
+			'orderby'      => 'name',
+			'show_count'   => $c,
+			'hierarchical' => $h,
+		);
+
+		if ( $d ) {
+			echo sprintf( '<form action="%s" method="get">', esc_url( home_url() ) );
+			$dropdown_id = ( $first_dropdown ) ? 'cat' : "{$this->id_base}-dropdown-{$this->number}";
+			$first_dropdown = false;
+
+			echo '<label class="screen-reader-text" for="' . esc_attr( $dropdown_id ) . '">' . $title . '</label>';
+
+			$cat_args['show_option_none'] = __( 'Select Category' );
+			$cat_args['id'] = $dropdown_id;
+
+			/**
+			 * Filters the arguments for the Categories widget drop-down.
+			 *
+			 * @since 2.8.0
+			 * @since 4.9.0 Added the `$instance` parameter.
+			 *
+			 * @see wp_dropdown_categories()
+			 *
+			 * @param array $cat_args An array of Categories widget drop-down arguments.
+			 * @param array $instance Array of settings for the current widget.
+			 */
+			wp_dropdown_categories( apply_filters( 'widget_categories_dropdown_args', $cat_args, $instance ) );
+
+			echo '</form>';
+			?>
+
+<script type='text/javascript'>
+/* <![CDATA[ */
+(function() {
+	var dropdown = document.getElementById( "<?php echo esc_js( $dropdown_id ); ?>" );
+	function onCatChange() {
+		if ( dropdown.options[ dropdown.selectedIndex ].value > 0 ) {
+			dropdown.parentNode.submit();
+		}
+	}
+	dropdown.onchange = onCatChange;
+})();
+/* ]]> */
+</script>
+
+<?php
+		} else {
+?>
+		<ul>
+<?php
+		$cat_args['title_li'] = '';
+
+		/**
+		 * Filters the arguments for the Categories widget.
+		 *
+		 * @since 2.8.0
+		 * @since 4.9.0 Added the `$instance` parameter.
+		 *
+		 * @param array $cat_args An array of Categories widget options.
+		 * @param array $instance Array of settings for the current widget.
+		 */
+		wp_list_categories( apply_filters( 'widget_categories_args', $cat_args, $instance ) );
+?>
+		</ul>
+<?php
+		}
+
+		echo $args['after_widget'];
+	}
+
+	/**
+	 * Handles updating settings for the current Categories widget instance.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param array $new_instance New settings for this instance as input by the user via
+	 *                            WP_Widget::form().
+	 * @param array $old_instance Old settings for this instance.
+	 * @return array Updated settings to save.
+	 */
+	public function update( $new_instance, $old_instance ) {
+		$instance = $old_instance;
+		$instance['title'] = sanitize_text_field( $new_instance['title'] );
+		$instance['count'] = !empty($new_instance['count']) ? 1 : 0;
+		$instance['hierarchical'] = !empty($new_instance['hierarchical']) ? 1 : 0;
+		$instance['dropdown'] = !empty($new_instance['dropdown']) ? 1 : 0;
+
+		return $instance;
+	}
+
+	/**
+	 * Outputs the settings form for the Categories widget.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param array $instance Current settings.
+	 */
+	public function form( $instance ) {
+		//Defaults
+		$instance = wp_parse_args( (array) $instance, array( 'title' => '') );
+		$title = sanitize_text_field( $instance['title'] );
+		$count = isset($instance['count']) ? (bool) $instance['count'] :false;
+		$hierarchical = isset( $instance['hierarchical'] ) ? (bool) $instance['hierarchical'] : false;
+		$dropdown = isset( $instance['dropdown'] ) ? (bool) $instance['dropdown'] : false;
+		?>
+		<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>
+
+		<p><input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('dropdown'); ?>" name="<?php echo $this->get_field_name('dropdown'); ?>"<?php checked( $dropdown ); ?> />
+		<label for="<?php echo $this->get_field_id('dropdown'); ?>"><?php _e( 'Display as dropdown' ); ?></label><br />
+
+		<input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('count'); ?>" name="<?php echo $this->get_field_name('count'); ?>"<?php checked( $count ); ?> />
+		<label for="<?php echo $this->get_field_id('count'); ?>"><?php _e( 'Show post counts' ); ?></label><br />
+
+		<input type="checkbox" class="checkbox" id="<?php echo $this->get_field_id('hierarchical'); ?>" name="<?php echo $this->get_field_name('hierarchical'); ?>"<?php checked( $hierarchical ); ?> />
+		<label for="<?php echo $this->get_field_id('hierarchical'); ?>"><?php _e( 'Show hierarchy' ); ?></label></p>
+		<?php
+	}
+
+}