Fix potential crash in Rx2 and Rx3 asFlow extension (#2333)

Fixes #2104
Fixes #2299

Co-authored-by: Louis CAD <[email protected]>

Author: qwwdfsad

reactive/kotlinx-coroutines-rx2/src/RxConvert.kt

@@ -81,7 +81,13 @@ public fun <T: Any> ObservableSource<T>.asFlow(): Flow<T> = callbackFlow {
     val observer = object : Observer<T> {
         override fun onComplete() { close() }
         override fun onSubscribe(d: Disposable) { if (!disposableRef.compareAndSet(null, d)) d.dispose() }
-        override fun onNext(t: T) { sendBlocking(t) }
+        override fun onNext(t: T) {
+            try {
+                sendBlocking(t)
+            } catch (ignored: Throwable) { // TODO: Replace when this issue is fixed: https://github.com/Kotlin/kotlinx.coroutines/issues/974
+                // Is handled by the downstream flow
+            }
+        }
         override fun onError(e: Throwable) { close(e) }
     }
 

reactive/kotlinx-coroutines-rx2/test/ObservableSourceAsFlowStressTest.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.rx2
+
+import io.reactivex.*
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.*
+import kotlinx.coroutines.flow.*
+import org.junit.*
+import java.util.concurrent.*
+
+class ObservableSourceAsFlowStressTest : TestBase() {
+
+    private val iterations = 100 * stressTestMultiplierSqrt
+
+    @Before
+    fun setup() {
+        ignoreLostThreads("RxComputationThreadPool-", "RxCachedWorkerPoolEvictor-", "RxSchedulerPurge-")
+    }
+
+    @Test
+    fun testAsFlowCancellation() = runTest {
+        repeat(iterations) {
+            val latch = Channel<Unit>(1)
+            var i = 0
+            val observable = Observable.interval(100L, TimeUnit.MICROSECONDS)
+                .doOnNext {  if (++i > 100) latch.offer(Unit) }
+            val job = observable.asFlow().launchIn(CoroutineScope(Dispatchers.Default))
+            latch.receive()
+            job.cancelAndJoin()
+        }
+    }
+}

reactive/kotlinx-coroutines-rx3/src/RxConvert.kt

@@ -81,7 +81,13 @@ public fun <T: Any> ObservableSource<T>.asFlow(): Flow<T> = callbackFlow {
     val observer = object : Observer<T> {
         override fun onComplete() { close() }
         override fun onSubscribe(d: Disposable) { if (!disposableRef.compareAndSet(null, d)) d.dispose() }
-        override fun onNext(t: T) { sendBlocking(t) }
+        override fun onNext(t: T) {
+            try {
+                sendBlocking(t)
+            } catch (ignored: Throwable) { // TODO: Replace when this issue is fixed: https://github.com/Kotlin/kotlinx.coroutines/issues/974
+                // Is handled by the downstream flow
+            }
+        }
         override fun onError(e: Throwable) { close(e) }
     }
 

reactive/kotlinx-coroutines-rx3/test/ObservableSourceAsFlowStressTest.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.rx3
+
+import io.reactivex.rxjava3.core.*
+import io.reactivex.rxjava3.exceptions.*
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.*
+import kotlinx.coroutines.flow.*
+import org.junit.*
+import java.util.concurrent.*
+
+class ObservableSourceAsFlowStressTest : TestBase() {
+
+    private val iterations = 100 * stressTestMultiplierSqrt
+
+    @Before
+    fun setup() {
+        ignoreLostThreads("RxComputationThreadPool-", "RxCachedWorkerPoolEvictor-", "RxSchedulerPurge-")
+    }
+
+    @Test
+    fun testAsFlowCancellation() = runTest {
+        repeat(iterations) {
+            val latch = Channel<Unit>(1)
+            var i = 0
+            val observable = Observable.interval(100L, TimeUnit.MICROSECONDS)
+                .doOnNext {  if (++i > 100) latch.offer(Unit) }
+            val job = observable.asFlow().launchIn(CoroutineScope(Dispatchers.Default))
+            latch.receive()
+            job.cancelAndJoin()
+        }
+    }
+}