Following in app purchase, app crashing on startup. productIdentifier=nil?

Question

I have a few users who have reported that after attempting an in app purchase the app is now crashing on startup. I have asked them to delete and reinstall the app which has

Answer 1

Elaborating on Shawn's answer, in - (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions you probably have some code like this:

- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions
{
    for (SKPaymentTransaction *transaction in transactions)
    {
        switch (transaction.transactionState)
        {
            case SKPaymentTransactionStatePurchased:

                                [self completeTransaction:transaction];

                                break;

                        case SKPaymentTransactionStateFailed:

                                [self failedTransaction:transaction];

                                break;

                        case SKPaymentTransactionStateRestored:

                                [self restoreTransaction:transaction];

                        default:

                                break;
        }     
    }
}

- (void) restoreTransaction: (SKPaymentTransaction *)transaction
{   
    /* Handle restore here */
    [[SKPaymentQueue defaultQueue] finishTransaction: transaction]; 
}

You can handle nil productIdentifiers in restoreTransaction: by adding a check to see if the productIdentifier is nil, like this:

- (void) restoreTransaction: (SKPaymentTransaction *)transaction
{   
    if (!transaction.originalTransaction.payment.productIdentifier) {
        NSLog(@"productIdentifier is nil; Apple bug?");
        [[SKPaymentQueue defaultQueue] finishTransaction: transaction];
        return;
    }

    /* Handle restore here */
    [[SKPaymentQueue defaultQueue] finishTransaction: transaction];
}

This technique fixed the problem for me in my app. The app started, logged "productIdentifier is nil; Apple bug?" and didn't crash. When I then manually re-restored transactions, Apple sent a valid transaction, and the app worked as designed.