Retrieves the author of the current comment.

If the comment has an empty comment_author field, then ‘Anonymous’ person is
assumed.

function get_comment_author( $comment_ID = 0 ) {
	$comment    = get_comment( $comment_ID );
	$comment_ID = ! empty( $comment->comment_ID ) ? $comment->comment_ID : $comment_ID;

	if ( empty( $comment->comment_author ) ) {
		$user = ! empty( $comment->user_id ) ? get_userdata( $comment->user_id ) : false;
		if ( $user ) {
			$author = $user->display_name;
		} else {
			$author = __( 'Anonymous' );
		}
	} else {
		$author = $comment->comment_author;
	}

	/**
	 * Filters the returned comment author name.
	 *
	 * @since 1.5.0
	 * @since 4.1.0 The `$comment_ID` and `$comment` parameters were added.
	 *
	 * @param string     $author     The comment author's username.
	 * @param string     $comment_ID The comment ID as a numeric string.
	 * @param WP_Comment $comment    The comment object.
	 */
	return apply_filters( 'get_comment_author', $author, $comment_ID, $comment );
}