WP_REST_Comments_Controller::check_is_comment_content_allowed( array $prepared_comment )

	protected function check_is_comment_content_allowed( $prepared_comment ) {
		$check = wp_parse_args(
			$prepared_comment,
			array(
				'comment_post_ID'      => 0,
				'comment_author'       => null,
				'comment_author_email' => null,
				'comment_author_url'   => null,
				'comment_parent'       => 0,
				'user_id'              => 0,
			)
		);

		/** This filter is documented in wp-includes/comment.php */
		$allow_empty = apply_filters( 'allow_empty_comment', false, $check );

		if ( $allow_empty ) {
			return true;
		}

		/*
		 * Do not allow a comment to be created with missing or empty
		 * comment_content. See wp_handle_comment_submission().
		 */
		return '' !== $check['comment_content'];
	}