woothemes / woocommerce

includes/class-wc-checkout.php

<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly
}

/**
 * Checkout
 *
 * The WooCommerce checkout class handles the checkout process, collecting user data and processing the payment.
 *
 * @class 		WC_Checkout
 * @version		2.1.0
 * @package		WooCommerce/Classes
 * @category		Class
 * @author 		WooThemes
 */
class WC_Checkout {

	/** @var array Array of posted form data. */
	public $posted;

	/** @var array Array of fields to display on the checkout. */
	public $checkout_fields;

	/** @var bool Whether or not the user must create an account to checkout. */
	public $must_create_account;

	/** @var bool Whether or not signups are allowed. */
	public $enable_signup;

	/** @var object The shipping method being used. */
	private $shipping_method;

The property $shipping_method is not used and could be removed.

	/** @var WC_Payment_Gateway|string The payment gateway being used. */
	private $payment_method;

	/** @var int ID of customer. */
	private $customer_id;

	/** @var array Where shipping_methods are stored. */
	public $shipping_methods;

	/**
	 * @var WC_Checkout The single instance of the class
	 * @since 2.1
	 */
	protected static $_instance = null;

	/** @var Bool */
	public $enable_guest_checkout;

	/**
	 * Main WC_Checkout Instance.
	 *
	 * Ensures only one instance of WC_Checkout is loaded or can be loaded.
	 *
	 * @since 2.1
	 * @static
	 * @return WC_Checkout Main instance
	 */
	public static function instance() {
		if ( is_null( self::$_instance ) )
			self::$_instance = new self();
		return self::$_instance;
	}

	/**
	 * Cloning is forbidden.
	 *
	 * @since 2.1
	 */
	public function __clone() {
		_doing_it_wrong( __FUNCTION__, __( 'Cheatin’ huh?', 'woocommerce' ), '2.1' );
	}

	/**
	 * Unserializing instances of this class is forbidden.
	 *
	 * @since 2.1
	 */
	public function __wakeup() {
		_doing_it_wrong( __FUNCTION__, __( 'Cheatin’ huh?', 'woocommerce' ), '2.1' );
	}

	/**
	 * Constructor for the checkout class. Hooks in methods and defines checkout fields.
	 *
	 * @access public
	 */
	public function __construct () {
		add_action( 'woocommerce_checkout_billing', array( $this,'checkout_form_billing' ) );
		add_action( 'woocommerce_checkout_shipping', array( $this,'checkout_form_shipping' ) );

		$this->enable_signup         = get_option( 'woocommerce_enable_signup_and_login_from_checkout' ) == 'yes' ? true : false;
		$this->enable_guest_checkout = get_option( 'woocommerce_enable_guest_checkout' ) == 'yes' ? true : false;
		$this->must_create_account   = $this->enable_guest_checkout || is_user_logged_in() ? false : true;

		// Define all Checkout fields
		$this->checkout_fields['billing'] 	= WC()->countries->get_address_fields( $this->get_value( 'billing_country' ), 'billing_' );
		$this->checkout_fields['shipping'] 	= WC()->countries->get_address_fields( $this->get_value( 'shipping_country' ), 'shipping_' );

		if ( get_option( 'woocommerce_registration_generate_username' ) == 'no' ) {

This code seems to be duplicated across your project.

			$this->checkout_fields['account']['account_username'] = array(
				'type' 			=> 'text',
				'label' 		=> __( 'Account username', 'woocommerce' ),
				'required'      => true,
				'placeholder' 	=> _x( 'Username', 'placeholder', 'woocommerce' )
			);
		}

		if ( get_option( 'woocommerce_registration_generate_password' ) == 'no' ) {

This code seems to be duplicated across your project.

			$this->checkout_fields['account']['account_password'] = array(
				'type' 				=> 'password',
				'label' 			=> __( 'Account password', 'woocommerce' ),
				'required'          => true,
				'placeholder' 		=> _x( 'Password', 'placeholder', 'woocommerce' )
			);
		}

		$this->checkout_fields['order']	= array(
			'order_comments' => array(
				'type' => 'textarea',
				'class' => array('notes'),
				'label' => __( 'Order Notes', 'woocommerce' ),
				'placeholder' => _x('Notes about your order, e.g. special notes for delivery.', 'placeholder', 'woocommerce')
			)
		);

		$this->checkout_fields = apply_filters( 'woocommerce_checkout_fields', $this->checkout_fields );

		do_action( 'woocommerce_checkout_init', $this );
	}

	/**
	 * Checkout process.
	 */
	public function check_cart_items() {
		// When we process the checkout, lets ensure cart items are rechecked to prevent checkout
		do_action('woocommerce_check_cart_items');
	}

	/**
	 * Output the billing information form.
	 */
	public function checkout_form_billing() {
		wc_get_template( 'checkout/form-billing.php', array( 'checkout' => $this ) );
	}

	/**
	 * Output the shipping information form.
	 */
	public function checkout_form_shipping() {
		wc_get_template( 'checkout/form-shipping.php', array( 'checkout' => $this ) );
	}

	/**
	 * Create an order. Error codes:
	 * 		520 - Cannot insert order into the database.
	 * 		521 - Cannot get order after creation.
	 * 		522 - Cannot update order.
	 * 		525 - Cannot create line item.
	 * 		526 - Cannot create fee item.
	 * 		527 - Cannot create shipping item.
	 * 		528 - Cannot create tax item.
	 * 		529 - Cannot create coupon item.
	 * @access public
	 * @throws Exception
	 * @return int|WP_ERROR
	 */
	public function create_order() {
		global $wpdb;

		// Give plugins the opportunity to create an order themselves
		if ( $order_id = apply_filters( 'woocommerce_create_order', null, $this ) ) {
			return $order_id;
		}

		try {
			// Start transaction if available
			wc_transaction_query( 'start' );

			$order_data = array(
				'status'        => apply_filters( 'woocommerce_default_order_status', 'pending' ),
				'customer_id'   => $this->customer_id,
				'customer_note' => isset( $this->posted['order_comments'] ) ? $this->posted['order_comments'] : '',
				'cart_hash'     => md5( json_encode( wc_clean( WC()->cart->get_cart_for_session() ) ) . WC()->cart->total ),
				'created_via'   => 'checkout',
			);

			// Insert or update the post data
			$order_id = absint( WC()->session->order_awaiting_payment );

			/**
			 * If there is an order pending payment, we can resume it here so
			 * long as it has not changed. If the order has changed, i.e.
			 * different items or cost, create a new order. We use a hash to
			 * detect changes which is based on cart items + order total.
			 */
			if ( $order_id && $order_data['cart_hash'] === get_post_meta( $order_id, '_cart_hash', true ) && ( $order = wc_get_order( $order_id ) ) && $order->has_status( array( 'pending', 'failed' ) ) ) {

				$order_data['order_id'] = $order_id;
				$order                  = wc_update_order( $order_data );

				if ( is_wp_error( $order ) ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 522 ) );
				} else {
					$order->remove_order_items();
					do_action( 'woocommerce_resume_order', $order_id );
				}

			} else {

				$order = wc_create_order( $order_data );

				if ( is_wp_error( $order ) ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 520 ) );
				} elseif ( false === $order ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 521 ) );
				} else {
					$order_id = $order->id;
					do_action( 'woocommerce_new_order', $order_id );
				}
			}

			// Store the line items to the new/resumed order
			foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) {
				$item_id = $order->add_product(
					$values['data'],
					$values['quantity'],
					array(
						'variation' => $values['variation'],
						'totals'    => array(
							'subtotal'     => $values['line_subtotal'],
							'subtotal_tax' => $values['line_subtotal_tax'],
							'total'        => $values['line_total'],
							'tax'          => $values['line_tax'],
							'tax_data'     => $values['line_tax_data'] // Since 2.2
						)
					)
				);

				if ( ! $item_id ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 525 ) );
				}

				// Allow plugins to add order item meta
				do_action( 'woocommerce_add_order_item_meta', $item_id, $values, $cart_item_key );
			}

			// Store fees
			foreach ( WC()->cart->get_fees() as $fee_key => $fee ) {
				$item_id = $order->add_fee( $fee );

				if ( ! $item_id ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 526 ) );
				}

				// Allow plugins to add order item meta to fees
				do_action( 'woocommerce_add_order_fee_meta', $order_id, $item_id, $fee, $fee_key );
			}

			// Store shipping for all packages
			foreach ( WC()->shipping->get_packages() as $package_key => $package ) {
				if ( isset( $package['rates'][ $this->shipping_methods[ $package_key ] ] ) ) {
					$item_id = $order->add_shipping( $package['rates'][ $this->shipping_methods[ $package_key ] ] );

					if ( ! $item_id ) {
						throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 527 ) );
					}

					// Allows plugins to add order item meta to shipping
					do_action( 'woocommerce_add_shipping_order_item', $order_id, $item_id, $package_key );
				}
			}

			// Store tax rows
			foreach ( array_keys( WC()->cart->taxes + WC()->cart->shipping_taxes ) as $tax_rate_id ) {
				if ( $tax_rate_id && ! $order->add_tax( $tax_rate_id, WC()->cart->get_tax_amount( $tax_rate_id ), WC()->cart->get_shipping_tax_amount( $tax_rate_id ) ) && apply_filters( 'woocommerce_cart_remove_taxes_zero_rate_id', 'zero-rated' ) !== $tax_rate_id ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 528 ) );
				}
			}

			// Store coupons
			foreach ( WC()->cart->get_coupons() as $code => $coupon ) {
				if ( ! $order->add_coupon( $code, WC()->cart->get_coupon_discount_amount( $code ), WC()->cart->get_coupon_discount_tax_amount( $code ) ) ) {
					throw new Exception( sprintf( __( 'Error %d: Unable to create order. Please try again.', 'woocommerce' ), 529 ) );
				}
			}

			// Billing address
			$billing_address = array();
			if ( $this->checkout_fields['billing'] ) {

This code seems to be duplicated across your project.

				foreach ( array_keys( $this->checkout_fields['billing'] ) as $field ) {
					$field_name = str_replace( 'billing_', '', $field );
					$billing_address[ $field_name ] = $this->get_posted_address_data( $field_name );
				}
			}

			// Shipping address.
			$shipping_address = array();
			if ( $this->checkout_fields['shipping'] ) {

This code seems to be duplicated across your project.

				foreach ( array_keys( $this->checkout_fields['shipping'] ) as $field ) {
					$field_name = str_replace( 'shipping_', '', $field );
					$shipping_address[ $field_name ] = $this->get_posted_address_data( $field_name, 'shipping' );
				}
			}

			$order->set_address( $billing_address, 'billing' );
			$order->set_address( $shipping_address, 'shipping' );
			$order->set_payment_method( $this->payment_method );

It seems like $this->payment_method can also be of type string; however, WC_Abstract_Order::set_payment_method() does only seem to accept object<WC_Payment_Gateway>, maybe add an additional type check?

			$order->set_total( WC()->cart->shipping_total, 'shipping' );
			$order->set_total( WC()->cart->get_cart_discount_total(), 'cart_discount' );
			$order->set_total( WC()->cart->get_cart_discount_tax_total(), 'cart_discount_tax' );
			$order->set_total( WC()->cart->tax_total, 'tax' );
			$order->set_total( WC()->cart->shipping_tax_total, 'shipping_tax' );
			$order->set_total( WC()->cart->total );

			// Update user meta
			if ( $this->customer_id ) {
				if ( apply_filters( 'woocommerce_checkout_update_customer_data', true, $this ) ) {
					foreach ( $billing_address as $key => $value ) {
						update_user_meta( $this->customer_id, 'billing_' . $key, $value );
					}
					if ( WC()->cart->needs_shipping() ) {
						foreach ( $shipping_address as $key => $value ) {
							update_user_meta( $this->customer_id, 'shipping_' . $key, $value );
						}
					}
				}
				do_action( 'woocommerce_checkout_update_user_meta', $this->customer_id, $this->posted );
			}

			// Let plugins add meta
			do_action( 'woocommerce_checkout_update_order_meta', $order_id, $this->posted );

			// If we got here, the order was created without problems!
			wc_transaction_query( 'commit' );

		} catch ( Exception $e ) {
			// There was an error adding order data!
			wc_transaction_query( 'rollback' );
			return new WP_Error( 'checkout-error', $e->getMessage() );
		}

		return $order_id;
	}

	/**
	 * Process the checkout after the confirm order button is pressed.
	 */
	public function process_checkout() {
		try {
			if ( empty( $_POST['_wpnonce'] ) || ! wp_verify_nonce( $_POST['_wpnonce'], 'woocommerce-process_checkout' ) ) {
				WC()->session->set( 'refresh_totals', true );
				throw new Exception( __( 'We were unable to process your order, please try again.', 'woocommerce' ) );
			}

			if ( ! defined( 'WOOCOMMERCE_CHECKOUT' ) ) {
				define( 'WOOCOMMERCE_CHECKOUT', true );
			}

			// Prevent timeout
			@set_time_limit(0);

			do_action( 'woocommerce_before_checkout_process' );

			if ( WC()->cart->is_empty() ) {
				throw new Exception( sprintf( __( 'Sorry, your session has expired. <a href="%s" class="wc-backward">Return to shop</a>', 'woocommerce' ), esc_url( wc_get_page_permalink( 'shop' ) ) ) );
			}

			do_action( 'woocommerce_checkout_process' );

			// Checkout fields (not defined in checkout_fields)
			$this->posted['terms']                     = isset( $_POST['terms'] ) ? 1 : 0;
			$this->posted['createaccount']             = isset( $_POST['createaccount'] ) && ! empty( $_POST['createaccount'] ) ? 1 : 0;
			$this->posted['payment_method']            = isset( $_POST['payment_method'] ) ? stripslashes( $_POST['payment_method'] ) : '';
			$this->posted['shipping_method']           = isset( $_POST['shipping_method'] ) ? $_POST['shipping_method'] : '';
			$this->posted['ship_to_different_address'] = isset( $_POST['ship_to_different_address'] ) ? true : false;

			if ( isset( $_POST['shiptobilling'] ) ) {
				_deprecated_argument( 'WC_Checkout::process_checkout()', '2.1', 'The "shiptobilling" field is deprecated. The template files are out of date' );

				$this->posted['ship_to_different_address'] = $_POST['shiptobilling'] ? false : true;
			}

			// Ship to billing only option
			if ( wc_ship_to_billing_address_only() ) {
				$this->posted['ship_to_different_address']  = false;
			}

			// Update customer shipping and payment method to posted method
			$chosen_shipping_methods = WC()->session->get( 'chosen_shipping_methods' );

			if ( isset( $this->posted['shipping_method'] ) && is_array( $this->posted['shipping_method'] ) ) {
				foreach ( $this->posted['shipping_method'] as $i => $value ) {
					$chosen_shipping_methods[ $i ] = wc_clean( $value );
				}
			}

			WC()->session->set( 'chosen_shipping_methods', $chosen_shipping_methods );
			WC()->session->set( 'chosen_payment_method', $this->posted['payment_method'] );

			// Note if we skip shipping
			$skipped_shipping = false;

			// Get posted checkout_fields and do validation
			foreach ( $this->checkout_fields as $fieldset_key => $fieldset ) {

				// Skip shipping if not needed
				if ( $fieldset_key == 'shipping' && ( $this->posted['ship_to_different_address'] == false || ! WC()->cart->needs_shipping_address() ) ) {
					$skipped_shipping = true;
					continue;
				}

				// Skip account if not needed
				if ( $fieldset_key == 'account' && ( is_user_logged_in() || ( $this->must_create_account == false && empty( $this->posted['createaccount'] ) ) ) ) {

It seems like you are loosely comparing two booleans. Considering using the strict comparison === instead.

					continue;
				}

				foreach ( $fieldset as $key => $field ) {

					if ( ! isset( $field['type'] ) ) {
						$field['type'] = 'text';
					}

					// Get Value
					switch ( $field['type'] ) {
						case "checkbox" :
							$this->posted[ $key ] = isset( $_POST[ $key ] ) ? 1 : 0;
						break;
						case "multiselect" :
							$this->posted[ $key ] = isset( $_POST[ $key ] ) ? implode( ', ', array_map( 'wc_clean', $_POST[ $key ] ) ) : '';
						break;
						case "textarea" :
							$this->posted[ $key ] = isset( $_POST[ $key ] ) ? wp_strip_all_tags( wp_check_invalid_utf8( stripslashes( $_POST[ $key ] ) ) ) : '';
						break;
						default :
							$this->posted[ $key ] = isset( $_POST[ $key ] ) ? ( is_array( $_POST[ $key ] ) ? array_map( 'wc_clean', $_POST[ $key ] ) : wc_clean( $_POST[ $key ] ) ) : '';
						break;
					}

					// Hooks to allow modification of value
					$this->posted[ $key ] = apply_filters( 'woocommerce_process_checkout_' . sanitize_title( $field['type'] ) . '_field', $this->posted[ $key ] );
					$this->posted[ $key ] = apply_filters( 'woocommerce_process_checkout_field_' . $key, $this->posted[ $key ] );

					// Validation: Required fields
					if ( isset( $field['required'] ) && $field['required'] && ( ! isset( $this->posted[ $key ] ) || "" === $this->posted[ $key ] ) ) {
						switch ( $fieldset_key ) {
							case 'shipping' :
								$field_label = sprintf( _x( 'Shipping %s', 'Shipping FIELDNAME', 'woocommerce' ), $field['label'] );
							break;
							case 'billing' :
								$field_label = sprintf( _x( 'Billing %s', 'Billing FIELDNAME', 'woocommerce' ), $field['label'] );
							break;
							default :
								$field_label = $field['label'];
							break;
						}
						wc_add_notice( apply_filters( 'woocommerce_checkout_required_field_notice', sprintf( _x( '%s is a required field.', 'FIELDNAME is a required field.', 'woocommerce' ), '<strong>' . $field_label . '</strong>' ), $field_label ), 'error' );
					}

					if ( ! empty( $this->posted[ $key ] ) ) {

						// Validation rules
						if ( ! empty( $field['validate'] ) && is_array( $field['validate'] ) ) {
							foreach ( $field['validate'] as $rule ) {
								switch ( $rule ) {
									case 'postcode' :
										$this->posted[ $key ] = strtoupper( str_replace( ' ', '', $this->posted[ $key ] ) );

										if ( ! WC_Validation::is_postcode( $this->posted[ $key ], $_POST[ $fieldset_key . '_country' ] ) ) :
											wc_add_notice( __( 'Please enter a valid postcode/ZIP.', 'woocommerce' ), 'error' );
										else :
											$this->posted[ $key ] = wc_format_postcode( $this->posted[ $key ], $_POST[ $fieldset_key . '_country' ] );
										endif;
									break;
									case 'phone' :

This code seems to be duplicated across your project.

										$this->posted[ $key ] = wc_format_phone_number( $this->posted[ $key ] );

										if ( ! WC_Validation::is_phone( $this->posted[ $key ] ) )
											wc_add_notice( '<strong>' . $field['label'] . '</strong> ' . __( 'is not a valid phone number.', 'woocommerce' ), 'error' );
									break;
									case 'email' :

This code seems to be duplicated across your project.

										$this->posted[ $key ] = strtolower( $this->posted[ $key ] );

										if ( ! is_email( $this->posted[ $key ] ) )
											wc_add_notice( '<strong>' . $field['label'] . '</strong> ' . __( 'is not a valid email address.', 'woocommerce' ), 'error' );
									break;
									case 'state' :
										// Get valid states
										$valid_states = WC()->countries->get_states( isset( $_POST[ $fieldset_key . '_country' ] ) ? $_POST[ $fieldset_key . '_country' ] : ( 'billing' === $fieldset_key ? WC()->customer->get_country() : WC()->customer->get_shipping_country() ) );

										if ( ! empty( $valid_states ) && is_array( $valid_states ) ) {
											$valid_state_values = array_flip( array_map( 'strtolower', $valid_states ) );

											// Convert value to key if set
											if ( isset( $valid_state_values[ strtolower( $this->posted[ $key ] ) ] ) ) {
												 $this->posted[ $key ] = $valid_state_values[ strtolower( $this->posted[ $key ] ) ];
											}
										}

										// Only validate if the country has specific state options
										if ( ! empty( $valid_states ) && is_array( $valid_states ) && sizeof( $valid_states ) > 0 ) {
											if ( ! in_array( $this->posted[ $key ], array_keys( $valid_states ) ) ) {
												wc_add_notice( '<strong>' . $field['label'] . '</strong> ' . __( 'is not valid. Please enter one of the following:', 'woocommerce' ) . ' ' . implode( ', ', $valid_states ), 'error' );
											}
										}
									break;
								}
							}
						}
					}
				}
			}

			// Update customer location to posted location so we can correctly check available shipping methods
			if ( isset( $this->posted['billing_country'] ) ) {
				WC()->customer->set_country( $this->posted['billing_country'] );
			}
			if ( isset( $this->posted['billing_state'] ) ) {
				WC()->customer->set_state( $this->posted['billing_state'] );
			}
			if ( isset( $this->posted['billing_postcode'] ) ) {
				WC()->customer->set_postcode( $this->posted['billing_postcode'] );
			}

			// Shipping Information
			if ( ! $skipped_shipping ) {

				// Update customer location to posted location so we can correctly check available shipping methods
				if ( isset( $this->posted['shipping_country'] ) ) {
					WC()->customer->set_shipping_country( $this->posted['shipping_country'] );
				}
				if ( isset( $this->posted['shipping_state'] ) ) {
					WC()->customer->set_shipping_state( $this->posted['shipping_state'] );
				}
				if ( isset( $this->posted['shipping_postcode'] ) ) {
					WC()->customer->set_shipping_postcode( $this->posted['shipping_postcode'] );
				}

			} else {

				// Update customer location to posted location so we can correctly check available shipping methods
				if ( isset( $this->posted['billing_country'] ) ) {
					WC()->customer->set_shipping_country( $this->posted['billing_country'] );
				}
				if ( isset( $this->posted['billing_state'] ) ) {
					WC()->customer->set_shipping_state( $this->posted['billing_state'] );
				}
				if ( isset( $this->posted['billing_postcode'] ) ) {
					WC()->customer->set_shipping_postcode( $this->posted['billing_postcode'] );
				}

			}

			// Update cart totals now we have customer address
			WC()->cart->calculate_totals();

			// Terms
			if ( ! isset( $_POST['woocommerce_checkout_update_totals'] ) && empty( $this->posted['terms'] ) && wc_get_page_id( 'terms' ) > 0 && apply_filters( 'woocommerce_checkout_show_terms', true ) ) {
				wc_add_notice( __( 'You must accept our Terms &amp; Conditions.', 'woocommerce' ), 'error' );
			}

			if ( WC()->cart->needs_shipping() ) {
				$shipping_country = WC()->customer->get_shipping_country();

				if ( empty( $shipping_country ) ) {
					wc_add_notice( __( 'Please enter an address to continue.', 'woocommerce' ), 'error' );
				} elseif ( ! in_array( WC()->customer->get_shipping_country(), array_keys( WC()->countries->get_shipping_countries() ) ) ) {
					wc_add_notice( sprintf( __( 'Unfortunately <strong>we do not ship %s</strong>. Please enter an alternative shipping address.', 'woocommerce' ), WC()->countries->shipping_to_prefix() . ' ' . WC()->customer->get_shipping_country() ), 'error' );
				}

				// Validate Shipping Methods
				$packages               = WC()->shipping->get_packages();
				$this->shipping_methods = WC()->session->get( 'chosen_shipping_methods' );

It seems like WC()->session->get('chosen_shipping_methods') can also be of type string. However, the property $shipping_methods is declared as type array. Maybe add an additional type check?

				foreach ( $packages as $i => $package ) {
					if ( ! isset( $package['rates'][ $this->shipping_methods[ $i ] ] ) ) {
						wc_add_notice( __( 'No shipping method has been selected. Please double check your address, or contact us if you need any help.', 'woocommerce' ), 'error' );
						$this->shipping_methods[ $i ] = '';
					}
				}
			}

			if ( WC()->cart->needs_payment() ) {
				// Payment Method
				$available_gateways = WC()->payment_gateways->get_available_payment_gateways();

				if ( ! isset( $available_gateways[ $this->posted['payment_method'] ] ) ) {
					$this->payment_method = '';
					wc_add_notice( __( 'Invalid payment method.', 'woocommerce' ), 'error' );
				} else {
					$this->payment_method = $available_gateways[ $this->posted['payment_method'] ];
					$this->payment_method->validate_fields();
				}
			} else {
				$available_gateways = array();
			}

			// Action after validation
			do_action( 'woocommerce_after_checkout_validation', $this->posted );

			if ( ! isset( $_POST['woocommerce_checkout_update_totals'] ) && wc_notice_count( 'error' ) == 0 ) {

				// Customer accounts
				$this->customer_id = apply_filters( 'woocommerce_checkout_customer_id', get_current_user_id() );

				if ( ! is_user_logged_in() && ( $this->must_create_account || ! empty( $this->posted['createaccount'] ) ) ) {

					$username     = ! empty( $this->posted['account_username'] ) ? $this->posted['account_username'] : '';
					$password     = ! empty( $this->posted['account_password'] ) ? $this->posted['account_password'] : '';
					$new_customer = wc_create_new_customer( $this->posted['billing_email'], $username, $password );

					if ( is_wp_error( $new_customer ) ) {
						throw new Exception( $new_customer->get_error_message() );
					}

					$this->customer_id = $new_customer;

It seems like $new_customer can also be of type object<WP_Error>. However, the property $customer_id is declared as type integer. Maybe add an additional type check?

					wc_set_customer_auth_cookie( $this->customer_id );

					// As we are now logged in, checkout will need to refresh to show logged in data
					WC()->session->set( 'reload_checkout', true );

					// Also, recalculate cart totals to reveal any role-based discounts that were unavailable before registering
					WC()->cart->calculate_totals();

					// Add customer info from other billing fields
					if ( $this->posted['billing_first_name'] && apply_filters( 'woocommerce_checkout_update_customer_data', true, $this ) ) {
						$userdata = array(
							'ID'           => $this->customer_id,
							'first_name'   => $this->posted['billing_first_name'] ? $this->posted['billing_first_name'] : '',
							'last_name'    => $this->posted['billing_last_name'] ? $this->posted['billing_last_name'] : '',
							'display_name' => $this->posted['billing_first_name'] ? $this->posted['billing_first_name'] : ''
						);
						wp_update_user( apply_filters( 'woocommerce_checkout_customer_userdata', $userdata, $this ) );
					}
				}

				// Do a final stock check at this point
				$this->check_cart_items();

				// Abort if errors are present
				if ( wc_notice_count( 'error' ) > 0 )
					throw new Exception();

				$order_id = $this->create_order();

				if ( is_wp_error( $order_id ) ) {
					throw new Exception( $order_id->get_error_message() );
				}

				do_action( 'woocommerce_checkout_order_processed', $order_id, $this->posted );

				// Process payment
				if ( WC()->cart->needs_payment() ) {

					// Store Order ID in session so it can be re-used after payment failure
					WC()->session->order_awaiting_payment = $order_id;

					// Process Payment
					$result = $available_gateways[ $this->posted['payment_method'] ]->process_payment( $order_id );

					// Redirect to success/confirmation/payment page
					if ( isset( $result['result'] ) && 'success' === $result['result'] ) {

						$result = apply_filters( 'woocommerce_payment_successful_result', $result, $order_id );

						if ( is_ajax() ) {
							wp_send_json( $result );
						} else {
							wp_redirect( $result['redirect'] );
							exit;
						}

					}

				} else {

					if ( empty( $order ) ) {
						$order = wc_get_order( $order_id );
					}

					// No payment was required for order
					$order->payment_complete();

					// Empty the Cart
					WC()->cart->empty_cart();

					// Get redirect
					$return_url = $order->get_checkout_order_received_url();

					// Redirect to success/confirmation/payment page
					if ( is_ajax() ) {
						wp_send_json( array(
							'result' 	=> 'success',
							'redirect'  => apply_filters( 'woocommerce_checkout_no_payment_needed_redirect', $return_url, $order )
						) );
					} else {
						wp_safe_redirect(
							apply_filters( 'woocommerce_checkout_no_payment_needed_redirect', $return_url, $order )
						);
						exit;
					}

				}

			}

		} catch ( Exception $e ) {
			if ( ! empty( $e ) ) {
				wc_add_notice( $e->getMessage(), 'error' );
			}
		}

		// If we reached this point then there were errors
		if ( is_ajax() ) {

			// only print notices if not reloading the checkout, otherwise they're lost in the page reload
			if ( ! isset( WC()->session->reload_checkout ) ) {
				ob_start();
				wc_print_notices();
				$messages = ob_get_clean();
			}

			$response = array(
				'result'	=> 'failure',
				'messages' 	=> isset( $messages ) ? $messages : '',
				'refresh' 	=> isset( WC()->session->refresh_totals ) ? 'true' : 'false',
				'reload'    => isset( WC()->session->reload_checkout ) ? 'true' : 'false'
			);

			unset( WC()->session->refresh_totals, WC()->session->reload_checkout );

			wp_send_json( $response );
		}
	}

	/**
	 * Get a posted address field after sanitization and validation.
	 * @param string $key
	 * @param string $type billing for shipping
	 * @return string
	 */
	public function get_posted_address_data( $key, $type = 'billing' ) {
		if ( 'billing' === $type || false === $this->posted['ship_to_different_address'] ) {
			$return = isset( $this->posted[ 'billing_' . $key ] ) ? $this->posted[ 'billing_' . $key ] : '';
		} else {
			$return = isset( $this->posted[ 'shipping_' . $key ] ) ? $this->posted[ 'shipping_' . $key ] : '';
		}

		// Use logged in user's billing email if neccessary
		if ( 'email' === $key && empty( $return ) && is_user_logged_in() ) {
			$current_user = wp_get_current_user();
			$return       = $current_user->user_email;
		}
		return $return;
	}

	/**
	 * Gets the value either from the posted data, or from the users meta data.
	 *
	 * @access public
	 * @param string $input
	 * @return string|null
	 */
	public function get_value( $input ) {
		if ( ! empty( $_POST[ $input ] ) ) {

			return wc_clean( $_POST[ $input ] );

		} else {

			$value = apply_filters( 'woocommerce_checkout_get_value', null, $input );

			if ( $value !== null ) {
				return $value;
			}

			// Get the billing_ and shipping_ address fields
			if ( isset( $this->checkout_fields['shipping'] ) && isset( $this->checkout_fields['billing'] ) ) {

				$address_fields = array_merge( $this->checkout_fields['billing'], $this->checkout_fields['shipping'] );

				if ( is_user_logged_in() && is_array( $address_fields ) && array_key_exists( $input, $address_fields ) ) {
					$current_user = wp_get_current_user();

					if ( $meta = get_user_meta( $current_user->ID, $input, true ) ) {
						return $meta;
					}

					if ( $input == 'billing_email' ) {
						return $current_user->user_email;
					}
				}

			}

			switch ( $input ) {
				case 'billing_country' :
					return apply_filters( 'default_checkout_country', WC()->customer->get_country() ? WC()->customer->get_country() : '', 'billing' );
				case 'billing_state' :
					return apply_filters( 'default_checkout_state', WC()->customer->get_state() ? WC()->customer->get_state() : '', 'billing' );
				case 'billing_postcode' :
					return apply_filters( 'default_checkout_postcode', WC()->customer->get_postcode() ? WC()->customer->get_postcode() : '', 'billing' );
				case 'shipping_country' :
					return apply_filters( 'default_checkout_country', WC()->customer->get_shipping_country() ? WC()->customer->get_shipping_country() : '', 'shipping' );
				case 'shipping_state' :
					return apply_filters( 'default_checkout_state', WC()->customer->get_shipping_state() ? WC()->customer->get_shipping_state() : '', 'shipping' );
				case 'shipping_postcode' :
					return apply_filters( 'default_checkout_postcode', WC()->customer->get_shipping_postcode() ? WC()->customer->get_shipping_postcode() : '', 'shipping' );
				default :
					return apply_filters( 'default_checkout_' . $input, null, $input );
			}
		}
	}
}