Undeprecate ReceiveChannel.isEmpty

Author: qwwdfsad

kotlinx-coroutines-core/common/src/channels/AbstractChannel.kt

@@ -562,8 +562,7 @@ internal abstract class AbstractChannel<E> : AbstractSendChannel<E>(), Channel<E
     // ------ ReceiveChannel ------
 
     public final override val isClosedForReceive: Boolean get() = closedForReceive != null && isBufferEmpty
-    public final override val isEmpty: Boolean get() = empty
-    private val empty: Boolean get() = queue.nextNode !is Send && isBufferEmpty // TODO rename to `isEmpty`
+    public final override val isEmpty: Boolean get() = queue.nextNode !is Send && isBufferEmpty
 
     @Suppress("UNCHECKED_CAST")
     public final override suspend fun receive(): E {
@@ -750,7 +749,7 @@ internal abstract class AbstractChannel<E> : AbstractSendChannel<E>(), Channel<E
     private fun <R> registerSelectReceive(select: SelectInstance<R>, block: suspend (E) -> R) {
         while (true) {
             if (select.isSelected) return
-            if (empty) {
+            if (isEmpty) {
                 val enqueueOp = TryEnqueueReceiveDesc(select, block as (suspend (E?) -> R), nullOnClose = false)
                 val enqueueResult = select.performAtomicIfNotSelected(enqueueOp) ?: return
                 when {
@@ -784,7 +783,7 @@ internal abstract class AbstractChannel<E> : AbstractSendChannel<E>(), Channel<E
     private fun <R> registerSelectReceiveOrNull(select: SelectInstance<R>, block: suspend (E?) -> R) {
         while (true) {
             if (select.isSelected) return
-            if (empty) {
+            if (isEmpty) {
                 val enqueueOp = TryEnqueueReceiveDesc(select, block, nullOnClose = true)
                 val enqueueResult = select.performAtomicIfNotSelected(enqueueOp) ?: return
                 when {

kotlinx-coroutines-core/common/src/channels/Channel.kt

@@ -151,11 +151,8 @@ public interface ReceiveChannel<out E> {
     /**
      * Returns `true` if the channel is empty (contains no elements) and the [receive] attempt will suspend.
      * This function returns `false` for [isClosedForReceive] channel.
-     *
-     * @suppress **Will be removed in next releases, no replacement.**
      */
     @ExperimentalCoroutinesApi
-    @Deprecated(level = DeprecationLevel.ERROR, message = "Will be removed in next releases without replacement")
     public val isEmpty: Boolean
 
     /**

kotlinx-coroutines-core/common/test/channels/ArrayChannelTest.kt

@@ -11,10 +11,12 @@ class ArrayChannelTest : TestBase() {
     @Test
     fun testSimple() = runTest {
         val q = Channel<Int>(1)
+        check(q.isEmpty)
         expect(1)
         val sender = launch {
             expect(4)
             q.send(1) // success -- buffered
+            check(!q.isEmpty)
             expect(5)
             q.send(2) // suspends (buffer full)
             expect(9)
@@ -23,27 +25,29 @@ class ArrayChannelTest : TestBase() {
         val receiver = launch {
             expect(6)
             check(q.receive() == 1) // does not suspend -- took from buffer
+            check(!q.isEmpty) // waiting sender's element moved to buffer
             expect(7)
             check(q.receive() == 2) // does not suspend (takes from sender)
             expect(8)
         }
         expect(3)
         sender.join()
         receiver.join()
+        check(q.isEmpty)
         finish(10)
     }
 
     @Test
     fun testClosedBufferedReceiveOrNull() = runTest {
         val q = Channel<Int>(1)
-        check(!q.isClosedForSend && !q.isClosedForReceive)
+        check(q.isEmpty && !q.isClosedForSend && !q.isClosedForReceive)
         expect(1)
         launch {
             expect(5)
-            check(q.isClosedForSend && !q.isClosedForReceive)
+            check(!q.isEmpty && q.isClosedForSend && !q.isClosedForReceive)
             assertEquals(42, q.receiveOrNull())
             expect(6)
-            check(q.isClosedForSend && q.isClosedForReceive)
+            check(!q.isEmpty && q.isClosedForSend && q.isClosedForReceive)
             assertEquals(null, q.receiveOrNull())
             expect(7)
         }
@@ -52,9 +56,9 @@ class ArrayChannelTest : TestBase() {
         expect(3)
         q.close() // goes on
         expect(4)
-        check(q.isClosedForSend && !q.isClosedForReceive)
+        check(!q.isEmpty && q.isClosedForSend && !q.isClosedForReceive)
         yield()
-        check(q.isClosedForSend && q.isClosedForReceive)
+        check(!q.isEmpty && q.isClosedForSend && q.isClosedForReceive)
         finish(8)
     }
 

kotlinx-coroutines-core/common/test/channels/RendezvousChannelTest.kt

@@ -11,6 +11,7 @@ class RendezvousChannelTest : TestBase() {
     @Test
     fun testSimple() = runTest {
         val q = Channel<Int>(Channel.RENDEZVOUS)
+        check(q.isEmpty)
         expect(1)
         val sender = launch {
             expect(4)
@@ -30,13 +31,14 @@ class RendezvousChannelTest : TestBase() {
         expect(3)
         sender.join()
         receiver.join()
+        check(q.isEmpty)
         finish(10)
     }
 
     @Test
     fun testClosedReceiveOrNull() = runTest {
         val q = Channel<Int>(Channel.RENDEZVOUS)
-        check(!q.isClosedForSend && !q.isClosedForReceive)
+        check(q.isEmpty && !q.isClosedForSend && !q.isClosedForReceive)
         expect(1)
         launch {
             expect(3)
@@ -49,9 +51,9 @@ class RendezvousChannelTest : TestBase() {
         q.send(42)
         expect(5)
         q.close()
-        check(q.isClosedForSend && q.isClosedForReceive)
+        check(!q.isEmpty && q.isClosedForSend && q.isClosedForReceive)
         yield()
-        check(q.isClosedForSend && q.isClosedForReceive)
+        check(!q.isEmpty && q.isClosedForSend && q.isClosedForReceive)
         finish(7)
     }
 
@@ -252,7 +254,7 @@ class RendezvousChannelTest : TestBase() {
             expect(1)
             send(bad)
         }
-        assertTrue(c.receive() === bad)
+        assertSame(c.receive(), bad)
         finish(2)
     }
 

kotlinx-coroutines-core/common/test/channels/TestChannelKind.kt

@@ -54,7 +54,6 @@ private class ChannelViaBroadcast<E>(
     val sub = broadcast.openSubscription()
 
     override val isClosedForReceive: Boolean get() = sub.isClosedForReceive
-    @Suppress("DEPRECATION_ERROR")
     override val isEmpty: Boolean get() = sub.isEmpty
 
     override suspend fun receive(): E = sub.receive()