ArrayIndexOutOfBoundsException crash from SDK when DP3T.sendIAmInfected() is called

[harri35]

ArrayIndexOutOfBoundsException crash from SDK when DP3T.sendIAmInfected() is called.
SDK: DP-3T SDK 1.0.0
GAEN: v1.3.1

I have an Android DP-3T related crash I am getting intermittently.

I do a clean install of our app. It uses the 1.0.0 DP-3T SDK and play-services-nearby-18.0.2-eap-v1.3.1.aar
I give all the permissions and GAEN works on this device. After our onboarding flow GAEN activates (Settings -> Google -> COVID-19 submenu also confirms this)

Immediately after install, I start our infection confirmation flow. In the flow as a user, I enter the onsetDate as today's date.
After our app has confirmed with our backend that I am allowed to confirm my infection then our app calls the DP-3T SDK:

DP3T.sendIAmInfected(activity, onsetDate, ...

DP-3T SDK crashes with

java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at com.google.gson.internal.$Gson$Types.getGenericSupertype($Gson$Types.java:248)
at com.google.gson.internal.$Gson$Types.getSupertype($Gson$Types.java:284)
at com.google.gson.internal.$Gson$Types.getCollectionElementType($Gson$Types.java:302)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory.create(CollectionTypeAdapterFactory.java:52)
at com.google.gson.Gson.getAdapter(Gson.java:458)
at com.google.gson.Gson.fromJson(Gson.java:926)
at com.google.gson.Gson.fromJson(Gson.java:892)
at com.google.gson.Gson.fromJson(Gson.java:841)
at com.google.gson.Gson.fromJson(Gson.java:813)
at org.dpppt.android.sdk.internal.util.Json.fromJson(Json.java:34)
at org.dpppt.android.sdk.internal.PendingKeyUploadStorage.getPendingKeys(PendingKeyUploadStorage.java:53)
at org.dpppt.android.sdk.internal.PendingKeyUploadStorage.addPendingKey(PendingKeyUploadStorage.java:85)
at org.dpppt.android.sdk.DP3T$1.onSuccess(DP3T.java:277)
at org.dpppt.android.sdk.DP3T$1.onSuccess(DP3T.java:269)
at org.dpppt.android.sdk.internal.backend.BackendReportRepository$1.onResponse(BackendReportRepository.java:54)
at retrofit2.DefaultCallAdapterFactory$ExecutorCallbackCall$1.lambda$onResponse$0$DefaultCallAdapterFactory$ExecutorCallbackCall$1(DefaultCallAdapterFactory.java:89)
at retrofit2.-$$Lambda$DefaultCallAdapterFactory$ExecutorCallbackCall$1$3wC8FyV4pyjrzrYL5U0mlYiviZw.run(Unknown Source:6)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

from the line PendingKeyUploadStorage.getInstance(activity).addPendingKey(delayedKey); inside the public void onSuccess(String authToken) callback.
As nobody will catch the Exception then our whole app also crashes.

So IMHO two issues here:

1. The crash itself
2. That the code running in the callback should also handle unexpected errors better and not crash the app, but just give a failure callback to the app.

[fbzli]

Any chance you have Proguard enabled? I can only reproduce this with obfuscation enabled specifically.

The PendingKey model appears to be in the wrong package/class, thus is not protected by the proguard exemption rules. We're going to fix that.

[harri35]

Hei!
The SDK we use is built by us, but it has
minifyEnabled false
for now

Same with our application. We are planning to use Proguard or R8 for our release, but this has not been correctly configured yet.

I am trying to reproduce this today myself, and have no luck thus far.

[fbzli]

Correction: I can also reproduce this with a release (not debug) build using coreLibraryDesugaringEnabled true , and Proguard disabled.

[harri35]

1. I tested with a release build with Proguard enabled - I can reproduce it this way easily, you are correct.

2. We do have "coreLibraryDesugaringEnabled true" on both debug and release.
   When I turn off Proguard / R8 by
   shrinkResources false setMinifyEnabled false
   then I can reproduce it also. But only on release.

Btw, we are using com.android.tools:desugar_jdk_libs:1.0.9

3. Debug still fine, like you said, can't reproduce it there.

I am starting to doubt myself now. Maybe I was on release then. Sorry about that.

[fbzli]

I pushed a fix. That should work with any Proguard configuration and/or core library desugaring enabled.