STPPaymentHandler.shared().handleNextAction can return status == .failed but no handleActionError

[mvarie]

Summary

Sometimes, when using STPPaymentHandler.shared().handleNextAction with test card 4000 0000 0000 3063 which requires 3DS, the completion block is called with a seemingly inconsistent set of parameters:

• status == .failed
• paymentIntent == populated and seemingly normal
• handleActionError == nil

It is unclear at this stage why the status is .failed, as no error object is offered.

Code to reproduce

I have been unable to identify a situation where this can be consistently reproduced.

My best guess is that cases that return an empty error handleActionError == nil, but a seemingly valid and populated paymentIntent, and a .failurestatus, pass by this line:

stripe-ios/Stripe/STPPaymentHandler.swift

Line 555 in 73306f3

completion(status, resultPaymentIntent, error)

.. but it's kind of a wild guess.

iOS version

14.4 , on physical device (iPhone 8)

Installation method

Swift Package Manager

SDK version

21.3.1

Other information

I wish I had more information to offer - I'll keep on monitoring these calls and see if I can find out more.

[csabol-stripe]

@mvarie thanks for the report, I'll see if I can find anything that looks suspicious here. If you manage to reproduce, could you look at the status of the returned PaymentIntent?

[mvarie]

@csabol-stripe the issue originates where your code checks if authenticationPresentingViewController can be presented on – in the two cases where it can't, you set canPresent = false, and then set an error message string, errorMessage = "error message...".

However, you then check if !canPresent && error != nil { .. and unfortunately error is nil; the errorMessage string never makes it to the caller and it's lost.

I was sometimes asking your sdk to present on a controller that was already presenting (my bad) but I never got the error message - that's why I was confused and trying to find a problem with the payment flow.

stripe-ios/Stripe/STPPaymentHandler.swift

Lines 1158 to 1195 in 73306f3

	/// Checks if authenticationContext.authenticationPresentingViewController can be presented on.
	/// @note Call this method after `prepareAuthenticationContextForPresentation:`
	func _canPresent(with authenticationContext: STPAuthenticationContext, error: inout NSError?)
	-> Bool
	{
	// Always allow in tests:
	if NSClassFromString("XCTest") != nil {
	return true
	}
	let presentingViewController = authenticationContext.authenticationPresentingViewController()
	var canPresent = true
	var errorMessage: String?
	// Is it in the window hierarchy?
	if presentingViewController.viewIfLoaded?.window == nil {
	canPresent = false
	errorMessage =
	"authenticationPresentingViewController is not in the window hierarchy. You should probably return the top-most view controller instead."
	}
	// Is it already presenting something?
	if presentingViewController.presentedViewController != nil {
	canPresent = false
	errorMessage =
	"authenticationPresentingViewController is already presenting. You should probably dismiss the presented view controller in `prepareAuthenticationContextForPresentation`."
	}
	if !canPresent && error != nil {
	error = _error(
	for: .requiresAuthenticationContextErrorCode,
	userInfo: errorMessage != nil
	? [
	STPError.errorMessageKey: errorMessage ?? ""
	] : nil)
	}
	return canPresent
	}

Thanks!

[csabol-stripe]

Thanks for the followup @mvarie! I've got a fix that we'll include in the next release so these errors are reported

[davidme-stripe]

This should be fixed in 21.4.0.