OnPurchaseDeferred seems to be mandatory and callback is called from a secondary thread

Good day,

I have noticed two weird behaviors on both Unity IAP 2.2.7 and the latest 3.0.2 release:

1) Despite what the comments and the documentation states,
IGooglePlayStoreExtensions.SetDeferredPurchaseListener MUST be set for Android as well. It is NOT an iOS only thing. In fact, the callback gets called on Android when e.g. a Slow response test card is used. If not set, when a deferred purchase is triggered, a Null Reference Exception crashes the app.

2) The deferred purchase callback is called (at least on Android) on a thread that is NOT the main one, thus causing lots of issues if the UI or anything Unity related is called or modified there. Failure and Success callbacks are instead called on the main thread. I have a workaround for this but seems to me that Deferred purchase callback should be called on the main tread as well.

I think those are bugs/issues but let me know otherwise, thanks!

 

Well, you need to trigger a a deferred purchase on an Android device. This means that you must setup a lot of stuff on the Google Play Console side of things (the app, the test users, the IAP items...), but provided that this is ready or that you already have an app setup this way you need to build the app for an Android device, and perform a IAP. Make sure your account is added to the test accounts and you will be given the option to choose between 4 possible credit cards: choose the Slow Card Always Approves and instead of ProcessPurchase or OnPurchaseFailed the Deferred Purchase Listener will be triggered.

1) if it was not set, the app will crash

2) it if was set, such callback is called on a secondary thread, so if I touch anything Unity related from there I will crash the app too

The sample is pretty simple, but as you can see all the effort is in setting up the google play environment to actually test it - unless you already have an app ready to be tested...

I don't think there is another way to actually trigger a deferred purchase - even if it was possible to do it from the Editor I doubt that the thread issue will show up there...

 

Hi,

sorry I probably wasn't clear in explaining how to reproduce.

You just need to run Sample IAP Project v2 on an Android device, initiate a test purchase and make sure the purchase is deferred. How you do that? The only way I know is to use the Slow test card, always approves/denies. If there is any other way please let me know.

(Of course, as you mentioned, you must create your products and application on Google, and this is what I meant in my previous message.)

Now, attach the device and open Android logcat provided with Unity - notice the TID of any Unity script.

I see that the example provided with Unity IAP has a Log in the deferred listener. At least until Unity IAP 3.0.2 that log in the deferred callback was printed by a thread with a different TID than any other unity related logs. If instead of just printing the log I call any method on any Unity related class, the app crashes - I assumed because of the different TID.

Also, if the deferred listener callback was not set, when it gets called, the app crashes and in the logcat I see a null reference exception happening down in the native stack.

If this explanation is clear but you still don't see it happening, I don't really know what to do - this was pretty consistent on both my low end android devices (I am running still Android 8.0 on both).

Just wanted to make sure that my explanation was correct, thanks a lot for your time and help!

 

Not registering the callback seems to be a crashing bug, in the sense that the game freezes and I have to kill it.

The OnDeferred callback bug instead is not a crashing bug but since we block the UI and show a waiting screen when the user initiates a purchase, and we remove it when either the purchase succeeds, fails or gets deferred, this error prevents us from hiding the waiting screen and re-enabling the user input, thus basically forcing the user to restart the app.

Here's a small sample:

Code (CSharp):

1. private void InitializeStuff()
2. {
3.  
4. ...
5.  
6. //
7. // Setup platform specific extensions - NOTE: if i don't set this, the game freezes in case of deferred purchase.
8. //
9. m_GooglePlayStoreExtensions.SetDeferredPurchaseListener(OnPurchaseDeferred);
10.  
11. ...
12.  
13. }
14.  
15. private void InitiatePurchase(string sProductId)
16. {
17.   m_kWaitingOverlay.gameObject.setActive(true);
18.  
19.  Debug.Log("Check the TID of this log!");
20.  
21.   m_kStoreController.InitiatePurchase(m_kStoreController.products.WithID(sProductId));
22. }
23.  
24. private void OnPurchaseDeferred(Product kProduct)
25. {
26. // This gets printed in logcat, on Unity IAP 3.0.2 this callback is called on a secondary thread (different TID). TID is different than the one printed in the InitiatePurchase()
27. Debug.LogFormat("[OnPurchaseDeferred] Purchase deferred : {0}", kProduct.definition.id);
28.  
29. // The following call is what causes the exception, I think
30. m_kWaitingOverlay.gameObject.setActive(false);
31.  
32. // Here is where I assume I see the exception log in logcat
33.  
34. // This DOES NOT get printed in logcat
35. Debug.Log("Test log");
36. }

I hope this is enough to help you figure out what we do in our game, let me know otherwise and thanks!

 

Hi!

So is there no way to disable the deferred purchases?
I saw in Google documentation that this deferred purchases are disabled as default and you have to enable it if you want to use it:
https://developer.android.com/google/play/billing/unity#deferred-purchases

 

Hi!

Please let me know what we should do inside the callback:

void OnPurchaseDeferred(Product product)
{
// Unlock the paid content or not? How we can know is it fail or success?
}

 

Thank you!

 

Hi @JeffDUnity3D,

We are also seeing our Android deferred purchase handler not being called on the main thread.

Code (CSharp):

1. googleConfigure.SetDeferredPurchaseListener(OnDeferredPurchase);

This causes a crash on device when doing anything Unity related in the callback.

This can of course be worked around, but it is messy. It is also not in keeping with the other part of Unity IAP which is all executed on the main thread.

Can this be addressed in a future release, please?

Thank you.

 

You can see an exception in LogCat:

"Unity UnityException: XXX can only be called from the main thread."

In my case XXX was "get_frameCount" caused by usage of "Time.frameCount" in a debug log.

You should be able to repro this simply by accessing Time.frameCount inside the deferred purchase callback (but pretty much any Unity API call would do, GameObejct.SetActive() etc).

 

We're using 4.1.2.

I don't see anything in the changelog of 4.1.3 that would change this behaviour: https://forum.unity.com/threads/uni...asset-store-v2-3-0.415517/page-2#post-7879486

 

Hi @JeffDUnity3D ,

Did you try using Time.frameCount in the OnDeferredPurchase function?

The problem will only surface if you try and use Unity API that can only be used on the main thread.

Thanks.

 

The syntax is correct, I cached the Google extensions to a variable.

I don't have the problem code anymore as I have refactored and added complexity to ensure it runs on the main thread.

Please try accessing Time.frameCount in your callback as I advised in my initial report of the issue.

 

I just hit it again:





Line 317 of IAPManager is:




The Dbg class uses Time.frameCount:

 

It's weird that you weren't able to reproduce... Maybe a Project Setting or device specific issue? I was testing on a OnePlus 6T with the mono backend in Unity 2019.4.31.

 

Hey @JeffDUnity3D ,

We use IL2CPP for all our Production builds, but nothing comes close to the speed of a local Mono Android build for on device iteration and testing

Due to Unity Ads we have been forced to use IL2CPP for a while now for all our iOS builds so nothing will need to change there with iOS 11, thanks for the heads up though!