IAP内购问题

// 用户信息与订单号保存到支付对象
SKMutablePayment * payment = [SKMutablePayment paymentWithProduct:product];
payment对象会保存一些参数。

#pragma mark - 苹果支付事务回调（SKPaymentTransactionObserver）
- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions {
    
    for (SKPaymentTransaction *transaction in transactions)
    {
        switch (transaction.transactionState)
        {
            case SKPaymentTransactionStateFailed:           //交易失败
            {
                [[SKPaymentQueue defaultQueue] finishTransaction: transaction];
            }
                break;
            case SKPaymentTransactionStatePurchased:        //交易完成
            {
                
            }
                break;
            case SKPaymentTransactionStatePurchasing:      //商品添加进列表
            {
                
            }
                break;
            case SKPaymentTransactionStateRestored:  // 恢复购买
            {
                
            }
        break;
            default:
                break;
        }
    }
} 

有些购买行为会在接收到SKPaymentTransactionStateFailed状态后，紧接着收到SKPaymentTransactionStatePurchased状态。
由于在接收到失败状态执行了[[SKPaymentQueue defaultQueue] finishTransaction: transaction]，接收到SKPaymentTransactionStatePurchased回调时，transaction是一个新的对象，transaction.payment对象存储的值已经不存在。