NullReferenceException in ParsePurchaseResult

[abittman]

We have a null reference thrown by Google Play Billing, with the following stacktrace:

Google.Play.Billing.GooglePlayStoreImpl.ParsePurchaseResult (UnityEngine.AndroidJavaObject billingResult, UnityEngine.AndroidJavaObject javaPurchasesList) (at <00000000000000000000000000000000>:0)
System.Action`2[T1,T2].Invoke (T1 arg1, T2 arg2) (at <00000000000000000000000000000000>:0)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <00000000000000000000000000000000>:0)
UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, System.Object[] args) (at <00000000000000000000000000000000>:0)
UnityEngine._AndroidJNIHelper.InvokeJavaProxyMethod (UnityEngine.AndroidJavaProxy proxy, System.IntPtr jmethodName, System.IntPtr jargs) (at <00000000000000000000000000000000>:0)
Rethrow as TargetInvocationException: Google.Play.Billing.Internal.PurchasesUpdatedListener.onPurchasesUpdated(UnityEngine.AndroidJavaObject,UnityEngine.AndroidJavaObject)
UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, System.Object[] args) (at <00000000000000000000000000000000>:0)
UnityEngine._AndroidJNIHelper.InvokeJavaProxyMethod (UnityEngine.AndroidJavaProxy proxy, System.IntPtr jmethodName, System.IntPtr jargs) (at <00000000000000000000000000000000>:0)

From our own investigation, it appears that the java purchase list is null and the store is commonly trying to reconnect.

Most reports also have the following log associated:
Google Play Store: Purchase failed with error code 'Error' and debug message: ''
And a null debug message isn't too useful to help track this sort of thing, but that might be best as a separate issue?

[HarrisonShort]

Hi @abittman!

Have you managed to figure this out? We are getting a similar NullReferenceException when attempting to use the Deferred proration mode when specifically downgrading subscriptions.

Google.Play.Billing.Internal.JniUtils.ParseJavaPurchaseList(UnityEngine.AndroidJavaObject javaPurchasesList)

Google.Play.Billing.GooglePlayStoreImpl.ParsePurchaseResult(UnityEngine.AndroidJavaObject billingResult, UnityEngine.AndroidJavaObject javaPurchasesList)

System.Action`2[T1,T2].Invoke(T1 arg1, T2 arg2)	

System.Reflection.MonoMethod.Invoke(System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture)
	
UnityEngine.AndroidJavaProxy.Invoke(System.String methodName, System.Object[] args)
	
UnityEngine._AndroidJNIHelper.InvokeJavaProxyMethod(UnityEngine.AndroidJavaProxy proxy, System.IntPtr jmethodName, System.IntPtr jargs)	

Rethrow as TargetInvocationException: Google.Play.Billing.Internal.PurchasesUpdatedListener.onPurchasesUpdated(UnityEngine.AndroidJavaObject,UnityEngine.AndroidJavaObject)	

UnityEngine.AndroidJavaProxy.Invoke(System.String methodName, System.Object[] args)

UnityEngine._AndroidJNIHelper.InvokeJavaProxyMethod(UnityEngine.AndroidJavaProxy proxy, System.IntPtr jmethodName, System.IntPtr jargs)

Currently this causes our app to hang because we have a loading overlay appear while our app is processing a purchase. When hard resetting the app, it appears that UnityIAP processes the Pending transaction and it successfully goes through (the information is sent to our database), however because we haven't been able to check whether or not this subscription purchase is a downgrade/crossgrade as this comes earlier than ProcessPurchase in our purchase flow, we cannot force the proration mode to be deferred.

I have also seen the following response, however it doesn't consistently appear:
Google Play Store: Purchase failed with error code 'DeveloperError' and debug message: ''

@Qing451800 I think this may actually be a separate issue to abittman's, so I can create a new issue for it if necessary. Please let me know!

EDIT: Worth noting is that there are no issues when upgrading a subscription using IMMEDIATE_WITH_TIME_PRORATION.

[abittman]

Hey @HarrisonShort it does look like we have similar, "potentially" related issues.

From what I could tell, it was most likely that the null reference was coming from the javaPurchasesList which it appears is a parameter in both of my ParsePurchaseResult function and your ParseJavaPurchaseList function. So that might be a good lead for google to look into?

I've had no luck with any fixes myself, and best I was ever able to figure out was that it's to do with that purchases list parameter coming in as null. I could do custom checks to fix it, but most likely just passing on the null reference would just cause other errors to appear later on.

We had this error appear after implementing slow purchases (or PENDING) for our game, and our senior programmer had some theories about an out of date google play store version, but we were never able to discover any reproduction steps.

Hopefully your report gives some more information for @Qing451800 to look into?

[Qing451800]

Thanks for the new information. We took a look at the original report but didn't find the root cause. With the new information, we will take another look. Any further clue is appreciated.

We would like to know how do you get this trace. If you get this from console's Vitals dashboard, is there an Android version or device information can be shared?

How often does this happen? Was the device doing the slow purchases at that time?

@HarrisonShort did this happen during upgrade/downgrade for you? What was the proration mode that's being used?

[HarrisonShort]

@HarrisonShort did this happen during upgrade/downgrade for you? What was the proration mode that's being used?

In our app, we have three subscriptions.

• Top tier (all functionality)
• Middle tier (functionality for this tier and lower tier)
• Lower tier (functionality for this tier only)

If the user has a subscription that is higher tier than the subscription they want to change to, we call Google.Play.Billing.IGooglePlayStoreExtensions.UpdateSubscription with the DEFERRED proration mode. If they are changing from a lower tier to a higher tier, we call Google.Play.Billing.IGooglePlayStoreExtensions.UpdateSubscription with IMMEDIATE_WITH_TIME_PRORATION. This occurs specifically when using the DEFERRED proration mode.

The native Google Play UI appears signalling that a subscription change is going to take place. After the purchase processes, the native UI disappears. Viewing the logs in logcat indicates that it is after this that the NullReferenceException in my other comment appears. I can tell that IStoreListener.ProcessPurchase is never called because no logs appear from this method.

EDIT: Additionally, we have yearly options for each of these subscription tiers. When changing from (for example) a middle tier monthly subscription to a middle tier yearly subscription, we also use the DEFERRED proration mode. This issue also occurs in this process.

Worth noting is that after getting this NullReferenceException, the subscription within Google Play does not actually update. If you hard reset the app, when UnityIAP initializes, it processes the purchase without a proration mode, and the Google Play subscription status updates. So the NullReferenceException appears to prevent the purchase from completing in the first place.

[HarrisonShort]

I've also created an issue on the Google Issue Tracker here.
@abittman Might be worth adding yours for potentially more eyes on it? Template for the Play Billing Library for Unity is here.