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Fix a racing condition when subscribing to a completed ScopeProvider. #135

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duanbo1983 wants to merge 2 commits into from
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Fix a racing condition when subscribing to a completed ScopeProvider. #135

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eae39d0
Fix a racing condition when subscribing a completed ScopeProvider.
duanbouber Nov 15, 2017
b08ea84
Address comments.
duanbouber Nov 16, 2017
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5 changes: 5 additions & 0 deletions autodispose/src/main/java/com/uber/autodispose/AutoDisposingObserverImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -46,15 +46,20 @@ final class AutoDisposingObserverImpl<T> implements AutoDisposingObserver<T> {
@Override public void onSuccess(Object o) {
callMainSubscribeIfNecessary(d);
AutoDisposingObserverImpl.this.dispose();
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@ZacSweers ZacSweers Nov 16, 2017

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This should be changed to AutoDisposableHelper.dispose(mainDisposable)

lifecycleDisposable.lazySet(AutoDisposableHelper.DISPOSED);
}

@Override public void onError(Throwable e) {
callMainSubscribeIfNecessary(d);
AutoDisposingObserverImpl.this.onError(e);
lifecycleDisposable.lazySet(AutoDisposableHelper.DISPOSED);
mainDisposable.lazySet(AutoDisposableHelper.DISPOSED);
}

@Override public void onComplete() {
callMainSubscribeIfNecessary(d);
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@duanbo1983 duanbo1983 Nov 16, 2017 •
edited by ZacSweers
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When subscribing to a completed ScopeProvider, callMainSubscribeIfNecessary() might be called here before the main source is subscribed, which triggers the DoubleSubscriptionsException.

lifecycleDisposable.lazySet(AutoDisposableHelper.DISPOSED);
mainDisposable.lazySet(AutoDisposableHelper.DISPOSED);
// Noop - we're unbound now
}
}),
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32 changes: 28 additions & 4 deletions autodispose/src/test/java/com/uber/autodispose/AutoDisposeObserverTest.java
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Expand Up @@ -16,13 +16,22 @@

package com.uber.autodispose;

import com.google.common.truth.BooleanSubject;
import com.uber.autodispose.observers.AutoDisposingObserver;
import com.uber.autodispose.test.RecordingObserver;

import org.junit.After;
import org.junit.Test;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

import io.reactivex.Observable;
import io.reactivex.ObservableEmitter;
import io.reactivex.ObservableOnSubscribe;
import io.reactivex.Observer;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.ProtocolViolationException;
import io.reactivex.functions.BiFunction;
import io.reactivex.functions.Cancellable;
import io.reactivex.functions.Consumer;
Expand All @@ -32,10 +41,6 @@
import io.reactivex.subjects.BehaviorSubject;
import io.reactivex.subjects.MaybeSubject;
import io.reactivex.subjects.PublishSubject;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import org.junit.After;
import org.junit.Test;

import static com.google.common.truth.Truth.assertThat;

Expand All @@ -49,6 +54,7 @@ public class AutoDisposeObserverTest {

@After public void resetPlugins() {
AutoDisposePlugins.reset();
RxJavaPlugins.reset();
}

@Test public void autoDispose_withMaybe_normal() {
Expand Down Expand Up @@ -171,6 +177,24 @@ public class AutoDisposeObserverTest {
assertThat(lifecycle.hasObservers()).isFalse();
}

@Test public void autoDispose_withScopeProviderCompleted_shouldNotReportDoubleSubscriptions() {
RxJavaPlugins.setErrorHandler(new Consumer<Throwable>() {
@Override
public void accept(Throwable throwable) throws Exception {
assertThat(throwable instanceof ProtocolViolationException).isFalse();
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@duanbo1983 duanbo1983 Nov 16, 2017 •
edited by ZacSweers
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This test case fails in master as:

Exception in thread "main" io.reactivex.exceptions.ProtocolViolationException: It is not allowed to subscribe with a(n) com.uber.autodispose.AutoDisposingObserverImpl multiple times. Please create a fresh instance of com.uber.autodispose.AutoDisposingObserverImpl and subscribe that to the target source instead.
	at com.uber.autodispose.AutoDisposeEndConsumerHelper.reportDoubleSubscription(AutoDisposeEndConsumerHelper.java:110)
	at com.uber.autodispose.AutoDisposeEndConsumerHelper.setOnce(AutoDisposeEndConsumerHelper.java:56)
	at com.uber.autodispose.AutoDisposingObserverImpl.onSubscribe(AutoDisposingObserverImpl.java:67)
	at io.reactivex.subjects.PublishSubject.subscribeActual(PublishSubject.java:85)
	at io.reactivex.Observable.subscribe(Observable.java:10842)
	at com.uber.autodispose.ObservableScoper$AutoDisposeObservable.subscribeActual(ObservableScoper.java:113)
	at io.reactivex.Observable.subscribe(Observable.java:10842)
	at com.uber.autodispose.ObservableScoper$1.subscribe(ObservableScoper.java:94)
	at com.uber.autodispose.AutoDisposeObserverTest.autoDispose_withScopeProviderCompleted_shouldNotReportDoubleSubscriptions(AutoDisposeObserverTest.java:192)

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@ZacSweers ZacSweers Nov 16, 2017

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I don't quite understand this test, as the ProtocolViolationException isn't obvious. Some sort of comment and asserting what you do expect should happen here

It also won't fail if this callback isn't hit, let's make it explicit somehow that we expect this callback to be hit

}
});
TestObserver<Integer> o = new TestObserver<>();
PublishSubject<Integer> source = PublishSubject.create();
MaybeSubject<Integer> scope = MaybeSubject.create();
scope.onComplete();
ScopeProvider scopeProvider = TestUtil.makeProvider(scope);
source.to(AutoDispose.with(scopeProvider).<Integer>forObservable())
.subscribe(o);
o.assertNoValues();
o.assertNoErrors();
}

@Test public void autoDispose_withProvider_withoutStartingLifecycle_shouldFail() {
BehaviorSubject<Integer> lifecycle = BehaviorSubject.create();
RecordingObserver<Integer> o = new RecordingObserver<>(LOGGER);
Expand Down