FATAL EXCEPTION: RxCachedThreadScheduler-4 or -1 or -2 or -3 ...

[yubaokang]

E/AndroidRuntime: FATAL EXCEPTION: RxCachedThreadScheduler-1
Process: goujiawang.gjstore, PID: 5960
java.io.InterruptedIOException: thread interrupted
at okio.Timeout.throwIfReached(Timeout.java:146)
at okio.Okio$2.read(Okio.java:135)
at okio.Buffer.writeAll(Buffer.java:993)
at okhttp3.RequestBody$3.writeTo(RequestBody.java:118)
at okhttp3.MultipartBody.writeOrCountBytes(MultipartBody.java:171)
at okhttp3.MultipartBody.writeTo(MultipartBody.java:113)
at okhttp3.logging.HttpLoggingInterceptor.intercept(HttpLoggingInterceptor.java:189)
at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:170)
at okhttp3.RealCall.execute(RealCall.java:60)
at retrofit2.OkHttpCall.execute(OkHttpCall.java:174)
at com.jakewharton.retrofit2.adapter.rxjava2.CallObservable.subscribeActual(CallObservable.java:41)
at io.reactivex.Observable.subscribe(Observable.java:10151)
at com.jakewharton.retrofit2.adapter.rxjava2.BodyObservable.subscribeActual(BodyObservable.java:34)
at io.reactivex.Observable.subscribe(Observable.java:10151)
at io.reactivex.internal.operators.flowable.FlowableFromObservable.subscribeActual(FlowableFromObservable.java:31)
at io.reactivex.Flowable.subscribe(Flowable.java:12172)
at io.reactivex.internal.operators.flowable.FlowableOnBackpressureLatest.subscribeActual(FlowableOnBackpressureLatest.java:31)
at io.reactivex.Flowable.subscribe(Flowable.java:12172)
at io.reactivex.internal.operators.flowable.FlowableFlatMap$MergeSubscriber.onNext(FlowableFlatMap.java:156)
at io.reactivex.internal.operators.flowable.FlowableFilter$FilterSubscriber.tryOnNext(FlowableFilter.java:72)
at io.reactivex.internal.operators.flowable.FlowableFromIterable$IteratorConditionalSubscription.slowPath(FlowableFromIterable.java:376)
at io.reactivex.internal.operators.flowable.FlowableFromIterable$BaseRangeSubscription.request(FlowableFromIterable.java:123)
at io.reactivex.internal.subscribers.BasicFuseableSubscriber.request(BasicFuseableSubscriber.java:152)
at io.reactivex.internal.operators.flowable.FlowableFlatMap$MergeSubscriber.onSubscribe(FlowableFlatMap.java:110)
at io.reactivex.internal.subscribers.BasicFuseableSubscriber.onSubscribe(BasicFuseableSubscriber.java:66)
at io.reactivex.internal.operators.flowable.FlowableFromIterable.subscribe(FlowableFromIterable.java:65)
at io.reactivex.internal.operators.flowable.FlowableFromIterable.subscribeActual(FlowableFromIterable.java:46)
at io.reactivex.Flowable.subscribe(Flowable.java:12172)
at io.reactivex.internal.operators.flowable.FlowableFilter.subscribeActual(FlowableFilter.java:35)
at io.reactivex.Flowable.subscribe(Flowable.java:12172)
at io.reactivex.internal.operators.flowable.FlowableFlatMap.subscribeActual(FlowableFlatMap.java:52)
at io.reactivex.Flowable.subscribe(Flowable.java:12172)
at io.reactivex.internal.operators.flowable.FlowableFlatMap.subscribeActual(FlowableFlatMap.java:52)
at io.reactivex.Flowable.subscribe(Flowable.java:12172)
at io.reactivex.internal.operators.flowable.FlowableSubscribeOn$SubscribeOnSubscriber.run(FlowableSubscribeOn.java:82)
at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:59)
at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:51)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:154)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:269)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)

  upload = Flowable.fromIterable(view.getUploadFiles())
                .filter(new Predicate<String>() {
                    @Override
                    public boolean test(String s) throws Exception {
                        return !TextUtils.isEmpty(s);
                    }
                })
                .flatMap(new Function<String, Publisher<BaseRes<UploadImagData>>>() {
                    @Override
                    public Publisher<BaseRes<UploadImagData>> apply(String s) throws Exception {
                        return RServices.get().uploadImg(view.getJSessionId(), UpLoadUtils.getRequestBody(s));
                    }
                })
                .compose(Transformer.<UploadImagData>retrofit())
                .subscribeWith(new RSubscriber<UploadImagData>(context) {
                    @Override
                    public void _onNext(UploadImagData uploadImagData) {
                        picPaths.add(uploadImagData.getId());
                    }

                    @Override
                    public void _onTEmpty() {
                        T.show(context, context.getString(R.string.submit_failed));
                    }

                    @Override
                    public void _onNetWorkError() {
                        T.show(context, context.getString(R.string.network_not_well));
                    }

                    @Override
                    public void _onReturnCodeError(String returnCode, String msg) {
                        T.show(context, msg);
                    }

                    @Override
                    public void _onComplete() {
                        submitMaterialQuality(picPaths);
                    }
                });

and when activity destroyed, I dispose it

 upload .dispose();

[akarnokd]

Did you hook RxJavaPlugins.onError by any chance?

[yubaokang]

@akarnokd no.

[yubaokang]

I had used retrofit2 to upload several image file. get the error ,how to deal with this problem?
thanks.

[JakeWharton]

This is a timeout from the HTTP client. Set larger timeouts if your uploads
will be taking longer. This exception is otherwise a completely normal
behavior of a network: it's a transient thing that became flaky and stopped
responding. Your application should be resilient to network failures and do
automatic retrying or prompt the user to retry.

On Fri, Nov 4, 2016 at 11:35 AM yubaokang notifications@github.com wrote:

I had used retrofit2 to upload several image file. get the error ,how to
deal with this problem?
thanks.

—
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[yubaokang]

oh,thanks. I will try it tomorrow at company.

[yubaokang]

This may be the exception to the server, but this should not cause the app to run, this exception RxJava can not be caught? Should not call the onError method?

[michaldrabik]

I'm having exactly the same issue. When online everything is good but crashes in airplane mode. Getting 'unknownHost' warnings etc. and then FATAL EXCEPTION: RxCachedThreadScheduler-1

Could we get an explanation why this exception crashes instead of going down to onError()?

Regards

[ssseasonnn]

I also met the same problem, what should I do?

[ssseasonnn]

Ok,I found the solution.

[radzio]

@ssseasonnn what solution have you found?

[VincentMasselis]

@radzio I've faced the problem, my mistake was to trying to emit a onError after the dispose.
For now, I surround any of my emitter.onError(), onNext(), onComplete() like that

if (!emitter.isDisposed())
    emitter.onNext(value)

Note : RxJava2 only, that doesn't crash on RxJava1

[dimsuz]

Hmm I have this crash when I use retrofit's RxJava2 adapter to send 2 or more requests at once like this:

Observable
  .fromIterable(listOf(params1, params2, params3))
  // every api call below will throw a `ConnectException`
  .flatMapSingle { params -> myApi.getApiCallSingle(params) }
  .toList()
  .subscribe({ }, { e -> println("error is ${e}") })

In this case the first error gets delivered successfully to the onError while all others seem to result in an app crash with similar message as OPs from AndroidRuntime:

         AndroidRuntime  E  FATAL EXCEPTION: RxCachedThreadScheduler-3
                         E  Process: com.example.dev, PID: 2686

I found that if I use concatMap instead of flatMap above - the crash goes away.

I am not sure what could be the source of this bug - rxjava2 itself or rxjava2 retrofit's call adapter...

Any help/hint would be appreciated.

[akarnokd]

@dimsuz It might be a problem in the dispose order inside RxJava - shutting down the scheduler before the fact of cancellation reaches the code that gets woken up by an interrupted blocking.

I'll try to hunt down the locations but I'm not yet sure if switching the dispose order has further implications or not.

[dimsuz]

Thank you! I might try to help you check, because for me it's rather easy: I can flip concatMap to flatMapSingle to reproduce it. Ping if this will be needed. By the way I forgot to mention that this happens on Android 6.0, but not on earlier version, but I am not sure why, because these are the core Java APIs, seemingly not touching Android SDK...

…

On Tue, Jan 31, 2017, 17:44 David Karnok ***@***.***> wrote: @dimsuz <https://github.com/dimsuz> It might be a problem in the dispose order inside RxJava - shutting down the scheduler before the fact of cancellation reaches the code that gets woken up by an interrupted blocking. I'll try to hunt down the locations but I'm not yet sure if switching the dispose order has further implications or not. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#4807 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AACnqM89urjhQEjK3wprqdaReJV2CL-Jks5rX1bFgaJpZM4Kpgwk> .

[akarnokd]

@dimsuz If you could write an unit test that reproduces the crash on desktop without the need for going online, that would be helpful.

[dimsuz]

@akarnokd I will try. I have tried to write a naive piece of code without using any retrofit stuff, synchonously and that wouldn't reproduce the issue, seems like concurrency/scheduling stuff is what triggers this :)

[akarnokd]

Okay. For diagnosing the problem, I can work with a retrofit-based code in my own repo. Once the issue is located, I'll likely be able to write an offline unit test for it.

[dimsuz]

Jake Wharton replied to my description of this issue which I posted earlier in kotlin's Slack channel:

That's how Rx works
The first error terminates the stream and the second undeliverable one goes to the plugins which goes to the thread uncaught handler.

After this explanation it seems like behavior I am getting is the correct one according to rx contract.

[dimsuz]

But in this case, this code should crash too, while it doesn't and prints "error!"...

Observable.fromIterable(listOf(1,2,3))
  .flatMapSingle { Single.fromCallable { throw RuntimeException() } }
  .toList()
  .subscribe({}, { println("error!") })

[akarnokd]

The problem is that we have to use thread interrupt to unblock blocking APIs. So when a blocking retrofit call is interrupted, it throws an InterruptedException but generally you can't know why and have to check some cancellation indication flag.

In RxJava, the interruption happens first and the set of the cancellation flag happens after. If the blocked thread is slow to wake up, it will see the cancellation flag and not emit the interrupt error. If the blocked thread wakes up fast or the cancel thread pauses between the interrupt and setting the flag, the woken up thread may find the flag not set and think it was a spurious interrupt and complain.

If the flag would be set before the interrupt is sent, a cancellation would never trigger the signal of the interrupted error.

[ssseasonnn]

@radzio Sorry to see it now, I used the following code to solve this problem.

static {
        RxJavaPlugins.setErrorHandler(new Consumer<Throwable>() {
            @Override
            public void accept(Throwable throwable) throws Exception {
                if (throwable instanceof InterruptedException) {
                    log("Thread interrupted");
                } else if (throwable instanceof InterruptedIOException) {
                    log("Io interrupted");
                } else if (throwable instanceof SocketException) {
                    log("Socket error");
                }
            }
        });
    }

[DavidMihola]

I seem to have a related error and am still confused about how to handle it...

When I disconnect the network, this code first correctly reports SocketTimeoutException in onError, but then immediately crashes with a ConnectException from somewhere within OkHttp.

compositeDisposable.add(
    Flowable.interval(10, TimeUnit.SECONDS)
        .subscribeOn(Schedulers.io())
        .flatMap(__ -> channelInfoManager.sendKeepAlive().toFlowable())
        .subscribe(
            Log::onNextWithTimber,
            Log::onErrorWithTimber
        )
);

If I replace the flatMap with either concatMap or switchMap it does not crash. Also, it didn't crash with RxJava 1.

Is this now the expected behavior and if so what exactly is the explanation and how should we deal with it?

[akarnokd]

@DavidMihola RxJava 1 by default dropped all excess exceptions and you didn't know about it. RxJava 2 doesn't lose them anymore. Could you try with the current RxJava 2 snapshot?

repositories {
    maven { url 'https://oss.jfrog.org/libs-snapshot' }
}

dependencies {
    compile 'io.reactivex.rxjava2:rxjava:2.0.0-DP0-SNAPSHOT'
}

[DavidMihola]

@akarnokd: Thanks for the reply!

OK, that required some fiddling - some other libraries kept "upgrading" RxJava from 2.0.0-DP0-SNAPSHOT to 2.0.1. But I added excludes everywhere and I am now reasonably certain that I am actually using the snapshot but that didn't solve the crashes...

[akarnokd]

You may suppress the extra exceptions by overriding the handler, similar to ssseasonnn's example.

[DavidMihola]

Yes, I saw that - but is it safe? That is, will I only "lose" any Exceptions that I wouldn't want to know about anyway (because they happened after a previous onError or after onCompleted) or is there any danger of missing valuable error information?

[akarnokd]

It depends on what you app does; RxJava can't do much to help you other than the hook itself. If it was me I'd let any RuntimeException crash the app as those are very likely due to programming errors and log/drop any checked exceptions because those are usually IO crashes in response to cancellations.

[DavidMihola]

OK, thanks again - we'll need to think that through some more!

FWIW, just "swallowing" the Exceptions with onErrorResumeNext also prevents the crashes, and may actually be closer to what we actually mean:

.flatMap(__ -> channelInfoManager.sendKeepAlive().toFlowable()
    .onErrorResumeNext(Flowable.empty())
)