UndeliverableException in ScanOperationApi21

[filippodelfra]

Hi,
I'm submitting this pull request because I'm receiving too many crashes from my application.

Fatal Exception: io.reactivex.exceptions.UndeliverableException: The exception could not be delivered to the consumer because it has already canceled/disposed the flow or the exception has nowhere to go to begin with. Further reading: https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#error-handling | com.polidea.rxandroidble2.exceptions.BleScanException: Scan failed because application registration failed (code 6)
at io.reactivex.plugins.RxJavaPlugins.onError + 367(RxJavaPlugins.java:367)
at io.reactivex.internal.operators.observable.ObservableCreate$CreateEmitter.onError + 73(ObservableCreate.java:73)
at com.polidea.rxandroidble2.internal.operations.ScanOperationApi21$1.onScanFailed + 79(ScanOperationApi21.java:79)
at android.bluetooth.le.BluetoothLeScanner$1.run + 556(BluetoothLeScanner.java:556)
at android.os.Handler.handleCallback + 873(Handler.java:873)
at android.os.Handler.dispatchMessage + 99(Handler.java:99)
at android.os.Looper.loop + 193(Looper.java:193)
at android.app.ActivityThread.main + 6718(ActivityThread.java:6718)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run + 493(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main + 858(ZygoteInit.java:858)`

The crash can be reproduced by starting a scan and immediately disposing the observable.

To fix it, I've done a small change in order to have the tryOnError() function inside the ScanOperationApi21 class.

Thanks!

[CLAassistant]

All committers have signed the CLA.

[dariuszseweryn]

Hello,
Thanks for the contribution. Unfortunately until you accept our Contributor Licence Agreement mentioned in the post above I cannot merge your changes.
Thank you!

[filippodelfra]

Hi,
Actually I have accepted it multiple times, but here is not updating for some reason.

[dariuszseweryn]

Perhaps you have signed it using a different email than account that has made the commit?

[filippodelfra]

Yes that was it. Thanks

[dariuszseweryn]

Would you mind to create a test suite for this case in OperationScanApi21Test.groovy? It seems to be perfectly testable

[dariuszseweryn]

Correct me if I am wrong but the test you have added does pass even before your changes to .tryOnError()?

I was thinking that the test case should add an RxJavaPlugins.setErrorHandler() which would capture all UndeliverableExceptions and it should be queried in then: if it did?

[filippodelfra]

You are right.
I've updated the test, let me know if it's working for you now.
Thanks

[dariuszseweryn]

I have looked once more and I think we're almost there. There are three inconsistent things in regards of the test — after that we can merge 👍

[dariuszseweryn]

Perfect! Thank you! 🚀

[dariuszseweryn]

And it should be available as version 1.10.2 shortly