Apple Pay no longer works with confirmPayment()

[luanalbineli]

Describe the bug
After we upgraded the lib's version from 11.3.0 to 12.0.2 we're no longer able to use confirmPayment() to complete the purchase using Apple Pay. It now throws a PlatformException with the Invalid Params message.

To Reproduce
Steps to reproduce the behavior:

1. Launches the Apple Pay wallsheet to create the payment intent:

final paymentMethod = await Stripe.instance
    .createPlatformPayPaymentMethod(
      params: PlatformPayPaymentMethodParams.applePay(
        applePayParams: ApplePayParams(
          cartItems: [
            ApplePayCartSummaryItem.immediate(
              label: 'Label',
              amount: '10.90',
            ),
          ],
          merchantCountryCode: 'IT',
          currencyCode: 'EUR',
        ),
      ),
    );

2. Create the payment intent to get the secret.
3. Confirm the payment:

await Stripe.instance.confirmPayment(
  paymentIntentClientSecret: 'secret_from_previous_step',
)

3. Observe a failure with exception:

PlatformException(Invalid Params, , , null) - #0      JSONMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:168:7)
#1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:367:18)
<asynchronous suspension>
#2      MethodChannel.invokeMapMethod (package:flutter/src/services/platform_channel.dart:567:43)
<asynchronous suspension>
#3      MethodChannelStripe.confirmPayment (package:stripe_platform_interface/src/method_channel_stripe.dart:132:20)
<asynchronous suspension>
#4      Stripe.confirmPayment (package:flutter_stripe/src/stripe.dart:374:29)

Expected behavior
The payment to be successfully processed using Apple Pay.

Smartphone / tablet

• Device: iPhone 9 (it should happen with any device)
• OS: iOS 16 (same from device)
• Package version: 12.0.2
• Flutter version 3.35.3

Additional context
The confirmPayment() method on Swift seems to be validating if the method channel is sending the params argument on the most recent versions:

func confirmPayment(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    guard let arguments = call.arguments as? FlutterMap,
          let paymentIntentClientSecret = arguments["paymentIntentClientSecret"] as? String,
          let options = arguments["options"] as? NSDictionary,
          let params = arguments["params"] as? NSDictionary else {
        result(FlutterError.invalidParams)
        return
    }
    
    confirmPayment(
        paymentIntentClientSecret: paymentIntentClientSecret,
        params: params,
        options: options,
        resolver: resolver(for: result),
        rejecter: rejecter(for: result)
    )
}

On version 11.3.0 the property could be nullable:

func confirmPayment(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    guard let arguments = call.arguments as? FlutterMap,
          let paymentIntentClientSecret = arguments["paymentIntentClientSecret"] as? String,
          let options = arguments["options"] as? NSDictionary else {
        result(FlutterError.invalidParams)
        return
    }
    let params = arguments["params"] as? NSDictionary
    confirmPayment(
        paymentIntentClientSecret: paymentIntentClientSecret,
        params: params,
        options: options,
        resolver: resolver(for: result),
        rejecter: rejecter(for: result)
    )
}

On the method channel implementation, this property can be nullable as well:

  @override
  Future<PaymentIntent> confirmPayment(
    String paymentIntentClientSecret,
    PaymentMethodParams? params,
    PaymentMethodOptions? options,
  ) async {
    final result = await _methodChannel
        .invokeMapMethod<String, dynamic>('confirmPayment', {
          'paymentIntentClientSecret': paymentIntentClientSecret,
          'params': params?.toJson(),
          'options': options?.toJson() ?? {},
        });

    return ResultParser<PaymentIntent>(
      parseJson: (json) => PaymentIntent.fromJson(json),
    ).parse(result: result!, successResultKey: 'paymentIntent');
  }

[pgiacomo69]

Same happens with iPhone 14 Pro Max, iOS 26.2, flutter_stripe 12.1.1. No problems with 11.3.0

[pgiacomo69]

The bug could be solved by #2287. But this solution would be brittle, since regression is granted when inporting a new version of React Native Stripe SDK.
The bug originates from ta change to

flutter_stripe/packages/stripe_ios/ios/stripe_ios/Sources/stripe_ios/Stripe Sdk/StripeSdkImpl.swift

Line 822 in 903f367

params: NSDictionary,

that made params non-nullable, this forced the change to

flutter_stripe/packages/stripe_ios/ios/stripe_ios/Sources/stripe_ios/StripePlugin.swift

Line 548 in 903f367

let params = arguments["params"] as? NSDictionary else {

to made params guarded.
Let's wait to see what @jonasbark and @remonh87 think about this.

[remonh87]

Thanks for the investigation. Can you check if the following helps:

await Stripe.instance.confirmPayment(
  paymentIntentClientSecret: 'secret_from_previous_step',
options: PaymentMethodOptions()  // just provide an empty payment method options object
)

I will take a longer look to it after the holidays but hopefully this work around wokrs

[pgiacomo69]

The problem is about ‘params’, not optionaI

[luanalbineli]

Thanks for the investigation. Can you check if the following helps:

await Stripe.instance.confirmPayment(
paymentIntentClientSecret: 'secret_from_previous_step',
options: PaymentMethodOptions() // just provide an empty payment method options object
)
I will take a longer look to it after the holidays but hopefully this work around wokrs

The problem is the data param (which is passed as params to the native code). The PaymentMethodParams class doesn't have an empty constructor

[remonh87]

I did some investigation and you should use confirmPlatformPayPaymentIntent instead. See https://github.com/flutter-stripe/flutter_stripe/blob/main/example/lib/screens/wallets/apple_pay_screen.dart

[luanalbineli]

Thanks for your reply @remonh87, but we would like to keep this process in separated calls (createPlatformPayPaymentMethod () and confirmPayment()), because we need to make a Back End call (with the PlatformPayPaymentMethod.paymentMethod.id to create the payment intent and perform some credit card checks) between each step. The method you're proposing does both things in one call, which is not suitable for us.

For now we've downgraded to 11.3.0 and payments started working again. I see this as a breaking change that at least needs to be documented if you're not intending to make changes to the code

[remonh87]

@luanalbineli got it the problem is you want to do some additional checks server side before confirming. I proposed an alternative fix in the pr and else I will create a ticket for the stripe team to fix it.