Drop-In UI crashes on iOS 9.x

[fraggjkee]

Hello everyone,

I've successfully integrated Braintree SDK in our Android project but currently struggling with Braintree SDK v4.2.1 for iOS. I'm using the Drop-In UI, here's my code (copy-pasted from the official documentation):

Controller:

#import "BraintreeCore.h"
#import "BraintreeUI.h"

@interface ECCheckoutViewController () <BTDropInViewControllerDelegate>

@property (nonatomic, strong) ClientToken *clientToken;
@property (nonatomic, strong) BTAPIClient *braintreeClient;

@end

@implementation ECCheckoutViewController

- (void)showDropInUI {
    // Init BraintreeClient with a client token
    NSString *clientTokenValue = [_clientToken clientToken];
    _braintreeClient = [[BTAPIClient alloc] initWithAuthorization:clientTokenValue];

    BTDropInViewController *dropInViewController = [[BTDropInViewController alloc]
                                                    initWithAPIClient:self.braintreeClient];
    dropInViewController.delegate = self;

    UIBarButtonItem *item = [[UIBarButtonItem alloc]
                             initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
                             target:self
                             action:@selector(userDidCancelPayment)];
    dropInViewController.navigationItem.leftBarButtonItem = item;
    UINavigationController *navigationController = [[UINavigationController alloc]
                                                    initWithRootViewController:dropInViewController];
    [self presentViewController:navigationController animated:YES completion:nil];
}

#pragma mark - Braintree

- (void)dropInViewController:(BTDropInViewController*)viewController
  didSucceedWithTokenization:(BTPaymentMethodNonce*)paymentMethodNonce {

    // Send payment method nonce to your server for processing
    [self postOrderWithNonce:paymentMethodNonce.nonce];
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)dropInViewControllerDidCancel:(__unused BTDropInViewController *)viewController {
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)userDidCancelPayment {
    [self dismissViewControllerAnimated:YES completion:nil];
}

@end

AppDelegate:

#import "BraintreeCore.h"

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Braintree
    [BTAppSwitch setReturnURLScheme:@"<bundle_id>.payments"];
}

- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
            options:(NSDictionary *)options {

    if ([url.scheme localizedCaseInsensitiveCompare:@"<bundle_id>.payments"] == NSOrderedSame) {
        NSString *sourceApplication = [options objectForKey:UIApplicationOpenURLOptionsSourceApplicationKey];
        return [BTAppSwitch handleOpenURL:url sourceApplication:sourceApplication];
    }

    return YES;
}

- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation {

    NSDictionary *options = @{UIApplicationOpenURLOptionsSourceApplicationKey: sourceApplication,
                              UIApplicationOpenURLOptionsAnnotationKey: annotation};

    return [self application:application openURL:url options:options];
}

LSApplicationQueriesSchemes:

URL types:

The Drop-In controller appears on the screen correctly, then I press the PayPal button and the app crashes almost immediately with the following error:

2016-02-10 22:15:01.663 Some Project[9573:4321387] *** Assertion failure in +[PPOTSimpleKeychain setData:forKey:], /Users/fraggjkee/Dropbox/Work/_iOS/SomeProject-ios/Pods/Braintree/BraintreePayPal/PayPalUtils/PPOTSimpleKeychain.m:81
2016-02-10 22:15:01.668 Some Project[9573:4321387] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Received -34018 from SecItemCopyMatching!'

ApplicationDelegate's methods aren't get called, the Drop-UI stays on the screen in a moment of crash. Any ideas what I am doing wrong guys? PayPall works quite well on iOS 8.4, by the way. Thanks in advance.

[skunkworks]

Hi @fraggjkee, I'll take a look right now.

[skunkworks]

Your implementation looks good.

The crash is caused by PayPal One Touch interacting with the iOS Keychain and getting back an error. I'm a bit concerned that you may be running into a bug with iOS itself:

SecItemAdd and SecItemCopyMatching returns error code -34018

It might be worthwhile to try out a few of the solutions posted there.

Are there certain scenarios where this crash occurs, or does it occur 100% of the time? Simulator or device?

[fraggjkee]

@skunkworks thank you for the quick response. I've enabled "KeyChain Sharing" as some people suggest at SO but unfortunately it didn't help. Will try other solutions tomorrow.

The crash always occurs on my physical device (iPhone 6 with the latest iOS version) but simulators work stable so far (both 8.x and 9.x).

[ryanphillipthomas]

Hi @skunkworks wanted to chime in and report I'm hitting the same issue here. Instead it's occurring in the app delegate and occurs during app startup. It's not 100% of the time and occurs on a physical device. I'm looking into the solutions you posted above.

[ryanphillipthomas]

@skunkworks Can you confirm that removing the paypal payment integration, but still having the drop in ui function with the normal payment options would avoid the crash all together?

[skunkworks]

@ryanphillipthomas You are correct that removing the PayPal subspec will work around this crash. We are actively investigating this issue and will report back with findings.

[skunkworks]

@ryanphillipthomas Are you able to duplicate this crash when the device is not connected to the Xcode debugger?

[ryanphillipthomas]

Hey @skunkworks thanks for getting back to me. I haven't hit it yet without being attached to debugger, in all of my runs I do recall being attached. That said the crash is so random.. I haven't been able to identify steps to repro. It's hard to tell if the issue would present itself when its not connected. Some research into soffes/SAMKeychain#52 shows most people are hitting it when debugging, but some are also reporting it on production as well.

[skunkworks]

Thanks for the quick response. Our tentative plan is to remove the assertion and find a way to recover gracefully if the keychain error occurs.

[skunkworks]

Hi, version 4.2.3 should prevent Keychain errors from asserting and crashing. Thanks for your guys' help!

[ryanphillipthomas]

Thanks @skunkworks!