Add callsInPlace to ReceiveChannel.consume (#2496)
Fixes #941
diff --git a/kotlinx-coroutines-core/common/src/channels/Channels.common.kt b/kotlinx-coroutines-core/common/src/channels/Channels.common.kt
index 60948f6..e3567e3 100644
--- a/kotlinx-coroutines-core/common/src/channels/Channels.common.kt
+++ b/kotlinx-coroutines-core/common/src/channels/Channels.common.kt
@@ -1,14 +1,16 @@
/*
- * Copyright 2016-2020 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.
*/
@file:JvmMultifileClass
@file:JvmName("ChannelsKt")
@file:Suppress("DEPRECATION_ERROR")
+@file:OptIn(ExperimentalContracts::class)
package kotlinx.coroutines.channels
import kotlinx.coroutines.*
import kotlinx.coroutines.selects.*
+import kotlin.contracts.*
import kotlin.coroutines.*
import kotlin.jvm.*
@@ -164,6 +166,9 @@
* The operation is _terminal_.
*/
public inline fun <E, R> ReceiveChannel<E>.consume(block: ReceiveChannel<E>.() -> R): R {
+ contract {
+ callsInPlace(block, InvocationKind.EXACTLY_ONCE)
+ }
var cause: Throwable? = null
try {
return block()
diff --git a/kotlinx-coroutines-core/common/test/BuilderContractsTest.kt b/kotlinx-coroutines-core/common/test/BuilderContractsTest.kt
index b20dd6b..5a96c54 100644
--- a/kotlinx-coroutines-core/common/test/BuilderContractsTest.kt
+++ b/kotlinx-coroutines-core/common/test/BuilderContractsTest.kt
@@ -1,9 +1,10 @@
/*
- * Copyright 2016-2020 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
+import kotlinx.coroutines.channels.*
import kotlinx.coroutines.selects.*
import kotlin.test.*
@@ -44,9 +45,22 @@
Job().apply { complete() }.onJoin {}
}
consume(s)
+
+
+ val ch: Int
+ val i = Channel<Int>()
+ i.consume {
+ ch = 321
+ }
+ consume(ch)
}
private fun consume(a: Int) {
- a.hashCode() // BE codegen verification
+ /*
+ * Verify the value is actually set correctly
+ * (non-zero, VerificationError is not triggered, can be read)
+ */
+ assertNotEquals(0, a)
+ assertEquals(a.hashCode(), a)
}
-}
\ No newline at end of file
+}