Make trySendBlocking available on K/N (Kotlin#3064)

Move trySendBlocking from the JVM to the concurrent source-set
to make it available on K/N.

Fixes Kotlin#2983

kotlinx-coroutines-core/jvm/src/channels/Channels.kt → kotlinx-coroutines-core/concurrent/src/channels/Channels.kt

@@ -1,65 +1,13 @@
-/*
- * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
- */
-
 @file:JvmMultifileClass
 @file:JvmName("ChannelsKt")
 
 package kotlinx.coroutines.channels
 
 import kotlinx.coroutines.*
+import kotlin.jvm.*
 
 /**
- * **Deprecated** blocking variant of send.
- * This method is deprecated in the favour of [trySendBlocking].
- *
- * `sendBlocking` is a dangerous primitive — it throws an exception
- * if the channel was closed or, more commonly, cancelled.
- * Cancellation exceptions in non-blocking code are unexpected and frequently
- * trigger internal failures.
- *
- * These bugs are hard-to-spot during code review and they forced users to write
- * their own wrappers around `sendBlocking`.
- * So this function is deprecated and replaced with a more explicit primitive.
- *
- * The real-world example of broken usage with Firebase:
- *
- * ```kotlin
- * callbackFlow {
- *     val listener = object : ValueEventListener {
- *         override fun onDataChange(snapshot: DataSnapshot) {
- *             // This line may fail and crash the app when the downstream flow is cancelled
- *             sendBlocking(DataSnapshot(snapshot))
- *         }
- *
- *         override fun onCancelled(error: DatabaseError) {
- *             close(error.toException())
- *         }
- *     }
- *
- *     firebaseQuery.addValueEventListener(listener)
- *     awaitClose { firebaseQuery.removeEventListener(listener) }
- * }
- * ```
- */
-@Deprecated(
-    level = DeprecationLevel.ERROR,
-    message = "Deprecated in the favour of 'trySendBlocking'. " +
-        "Consider handling the result of 'trySendBlocking' explicitly and rethrow exception if necessary",
-    replaceWith = ReplaceWith("trySendBlocking(element)")
-) // WARNING in 1.5.0, ERROR in 1.6.0, HIDDEN in 1.7.0
-public fun <E> SendChannel<E>.sendBlocking(element: E) {
-    // fast path
-    if (trySend(element).isSuccess)
-        return
-    // slow path
-    runBlocking {
-        send(element)
-    }
-}
-
-/**
- * Adds [element] into to this channel, **blocking** the caller while this channel is full,
+ * Adds [element] to this channel, **blocking** the caller while this channel is full,
  * and returning either [successful][ChannelResult.isSuccess] result when the element was added, or
  * failed result representing closed channel with a corresponding exception.
  *
@@ -77,9 +25,8 @@ public fun <E> SendChannel<E>.sendBlocking(element: E) {
  *
  * For this operation it is guaranteed that [failure][ChannelResult.failed] always contains an exception in it.
  *
- * @throws [InterruptedException] if the current thread is interrupted during the blocking send operation.
+ * @throws `InterruptedException` on JVM if the current thread is interrupted during the blocking send operation.
  */
-@Throws(InterruptedException::class)
 public fun <E> SendChannel<E>.trySendBlocking(element: E): ChannelResult<Unit> {
     /*
      * Sent successfully -- bail out.
@@ -94,3 +41,20 @@ public fun <E> SendChannel<E>.trySendBlocking(element: E): ChannelResult<Unit> {
         else ChannelResult.closed(r.exceptionOrNull())
     }
 }
+
+/** @suppress */
+@Deprecated(
+    level = DeprecationLevel.ERROR,
+    message = "Deprecated in the favour of 'trySendBlocking'. " +
+        "Consider handling the result of 'trySendBlocking' explicitly and rethrow exception if necessary",
+    replaceWith = ReplaceWith("trySendBlocking(element)")
+) // WARNING in 1.5.0, ERROR in 1.6.0, HIDDEN in 1.7.0
+public fun <E> SendChannel<E>.sendBlocking(element: E) {
+    // fast path
+    if (trySend(element).isSuccess)
+        return
+    // slow path
+    runBlocking {
+        send(element)
+    }
+}

kotlinx-coroutines-core/jvm/test/channels/ChannelsJvmTest.kt → kotlinx-coroutines-core/concurrent/test/channels/TrySendBlockingTest.kt

@@ -1,17 +1,16 @@
 /*
- * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
 package kotlinx.coroutines.channels
 
 import kotlinx.coroutines.*
-import org.junit.Test
 import kotlin.test.*
 
-class ChannelsJvmTest : TestBase() {
+class TrySendBlockingTest : TestBase() {
 
     @Test
-    fun testTrySendBlocking() {
+    fun testTrySendBlocking() = runBlocking<Unit> { // For old MM
         val ch = Channel<Int>()
         val sum = GlobalScope.async {
             var sum = 0