1.8.0-RC

• Implement the library for the Web Assembly (Wasm) for JavaScript (#3713). Thanks @igoriakovlev!
• On Android, ensure that Dispatchers.Main != Dispatchers.Main.immediate (#3545, #3963).
• kotlinx-coroutines-debug is published with the incorrect Java 9 module info (#3944).
• Major Kotlin version update: was 1.8.20, became 1.9.21.
• kotlinx-coroutines-test: set the default timeout of runTest to 60 seconds, added the ability to configure it on the JVM with the kotlinx.coroutines.test.default_timeout=10s (#3800).
• kotlinx-coroutines-test: fixed a bug that could lead to not all uncaught exceptions being reported after some tests failed (#3800).
• delay(Duration) rounds nanoseconds up to whole milliseconds and not down (#3920). Thanks @kevincianfarini!
• Dispatchers.Default and the default thread for background work are guaranteed to use the same context classloader as the object containing it them (#3832).
• It is guaranteed that by the time SharedFlow.collect suspends for the first time, it's registered as a subscriber for that SharedFlow (#3885). Before, it was also true, but not documented.
• Atomicfu version is updated to 0.23.1, and Kotlin/Native atomic transformations are enabled, reducing the footprint of coroutine-heavy code (#3954).
• Added a workaround for miscompilation of withLock on JS (#3881). Thanks @CLOVIS-AI!
• Small tweaks and documentation fixes.

1.7.3

• Disabled the publication of the multiplatform library metadata for the old (1.6 and earlier) KMP Gradle plugin (#3809).
• Fixed a bug introduced in 1.7.2 that disabled the coroutine debugger in IDEA (#3822).

1.7.2

Bug fixes and improvements

• Coroutines debugger no longer keeps track of coroutines with empty coroutine context (#3782).
• CopyableThreadContextElement now properly copies an element when crossing the coroutine boundary in flowOn (#3787). Thanks @wanyingd1996!
• Coroutine timeouts no longer prevent K/N newSingleThreadContext from closing (#3768).
• A non-linearizability in Mutex during tryLock/unlock sequence with owners is fixed (#3745).
• Atomicfu version is updated to 0.21.0.

1.7.1

Bug fixes and improvements

• Special characters in coroutine names in JSON dumps are supported (#3747)
• The binary compatibility of the experimental overload of runTest is restored (#3673)
• Channels that don't use onUndeliveredElement now allocate less memory (#3646)

1.7.0

Core API significant improvements

• New Channel implementation with significant performance improvements across the API (#3621).
• New select operator implementation: faster, more lightweight, and more robust (#3020).
• Mutex and Semaphore now share the same underlying data structure (#3020).
• Dispatchers.IO is added to K/N (#3205)
  • newFixedThreadPool and Dispatchers.Default implementations on K/N were wholly rewritten to support graceful growth under load (#3595).
• kotlinx-coroutines-test rework:
  • Add the timeout parameter to runTest for the whole-test timeout, 10 seconds by default (#3270). This replaces the configuration of quiescence timeouts, which is now deprecated (#3603).
  • The withTimeout exception messages indicate if the timeout used the virtual time (#3588).
  • TestCoroutineScheduler, runTest, and TestScope API are promoted to stable (#3622).
  • runTest now also fails if there were uncaught exceptions in coroutines not inherited from the test coroutine (#1205).

Breaking changes

• Old K/N memory model is no longer supported (#3375).
• New generic upper bounds were added to reactive integration API where the language since 1.8.0 dictates (#3393).
• kotlinx-coroutines-core and kotlinx-coroutines-jdk8 artifacts were merged into a single artifact (#3268).
• Artificial stackframes in stacktrace recovery no longer contain the \b symbol and are now navigable in IDE and supplied with proper documentation (#2291).
• CoroutineContext.isActive returns true for contexts without any job in them (#3300).

Bug fixes and improvements

• Kotlin version is updated to 1.8.20
• Atomicfu version is updated to 0.20.2.
• JavaFx version is updated to 17.0.2 in kotlinx-coroutines-javafx (#3671)..
• JPMS is supported (#2237). Thanks @lion7!
• BroadcastChannel and all the corresponding API are deprecated (#2680).
• Added all supported K/N targets (#3601, #812, #855).
• K/N Dispatchers.Default is backed by the number of threads equal to the number of available cores (#3366).
• Fixed an issue where some coroutines' internal exceptions were not properly serializable (#3328).
• Introduced Job.parent API (#3201).
• Fixed a bug when TestScheduler leaked cancelled jobs (#3398).
• TestScope.timeSource now provides comparable time marks (#3617). Thanks @hfhbd!
• Fixed an issue when cancelled withTimeout handles were preserved in JS runtime (#3440).
• Ensure awaitFrame only awaits a single frame when used from the main looper (#3432). Thanks @pablobaxter!
• Obsolete Class-Path attribute was removed from kotlinx-coroutines-debug.jar manifest (#3361).
• Fixed a bug when updateThreadContext operated on the parent context (#3411).
• Added new Flow.filterIsInstance extension (#3240).
• Dispatchers.Default thread name prefixes are now configurable with system property (#3231).
• Added Flow.timeout operator as @FlowPreview (#2624). Thanks @pablobaxter!
• Improved the performance of the future builder in case of exceptions (#3475). Thanks @He-Pin!
• Mono.awaitSingleOrNull now waits for the onComplete signal (#3487).
• Channel.isClosedForSend and Channel.isClosedForReceive are promoted from experimental to delicate (#3448).
• Fixed a data race in native EventLoop (#3547).
• Dispatchers.IO.limitedParallelism(valueLargerThanIOSize) no longer creates an additional wrapper (#3442). Thanks @dovchinnikov!
• Various @FlowPreview and @ExperimentalCoroutinesApi are promoted to experimental and stable respectively (#3542, #3097, #3548).
• Performance improvements in Dispatchers.Default and Dispatchers.IO (#3416, #3418).
• Fixed a bug when internal suspendCancellableCoroutineReusable might have hanged (#3613).
• Introduced internal API to process events in the current system dispatcher (#3439).
• Global CoroutineExceptionHandler is no longer invoked in case of unprocessed future failure (#3452).
• Performance improvements and reduced thread-local pressure for the withContext operator (#3592).
• Improved performance of DebugProbes (#3527).
• Fixed a bug when the coroutine debugger might have detected the state of a coroutine incorrectly (#3193).
• CoroutineDispatcher.asExecutor() runs tasks without dispatching if the dispatcher is unconfined (#3683). Thanks @odedniv!
• SharedFlow.toMutableList and SharedFlow.toSet lints are introduced (#3706).
• Channel.invokeOnClose is promoted to stable API (#3358).
• Improved lock contention in Dispatchers.Default and Dispatchers.IO during the startup phase (#3652).
• Fixed a bug that led to threads oversubscription in Dispatchers.Default (#3642).
• Fixed a bug that allowed limitedParallelism to perform dispatches even after the underlying dispatcher was closed (#3672).
• Fixed a bug that prevented stacktrace recovery when the exception's constructor from cause was selected (#3714).
• Improved sanitizing of stracktrace-recovered traces (#3714).
• Introduced an internal flag to disable uncaught exceptions reporting in tests as a temporary migration mechanism (#3736).
• Various documentation improvements and fixes.

1.7.0-RC

• Kotlin version is updated to 1.8.20.
• Atomicfu version is updated to 0.20.2.
• JavaFx version is updated to 17.0.2 in kotlinx-coroutines-javafx (#3671).
• previous-compilation-data.bin file is removed from JAR resources (#3668).
• CoroutineDispatcher.asExecutor() runs tasks without dispatching if the dispatcher is unconfined (#3683). Thanks @odedniv!
• SharedFlow.toMutableList lint overload is undeprecated (#3706).
• Channel.invokeOnClose is promoted to stable API (#3358).
• Improved lock contention in Dispatchers.Default and Dispatchers.IO during the startup phase (#3652).
• Fixed a bug that led to threads oversubscription in Dispatchers.Default (#3642).
• Fixed a bug that allowed limitedParallelism to perform dispatches even after the underlying dispatcher was closed (#3672).
• Restored binary compatibility of previously experimental TestScope.runTest(Long) (#3673).

1.7.0-Beta

Core API significant improvements

• New Channel implementation with significant performance improvements across the API (#3621).
• New select operator implementation: faster, more lightweight, and more robust (#3020).
• Mutex and Semaphore now share the same underlying data structure (#3020).
• Dispatchers.IO is added to K/N (#3205)
  • newFixedThreadPool and Dispatchers.Default implementations on K/N were wholly rewritten to support graceful growth under load (#3595).
• kotlinx-coroutines-test rework:
  • Add the timeout parameter to runTest for the whole-test timeout, 10 seconds by default (#3270). This replaces the configuration of quiescence timeouts, which is now deprecated (#3603).
  • The withTimeout exception messages indicate if the timeout used the virtual time (#3588).
  • TestCoroutineScheduler, runTest, and TestScope API are promoted to stable (#3622).
  • runTest now also fails if there were uncaught exceptions in coroutines not inherited from the test coroutine (#1205).

Breaking changes

• Old K/N memory model is no longer supported (#3375).
• New generic upper bounds were added to reactive integration API where the language since 1.8.0 dictates (#3393).
• kotlinx-coroutines-core and kotlinx-coroutines-jdk8 artifacts were merged into a single artifact (#3268).
• Artificial stackframes in stacktrace recovery no longer contain the \b symbol and are now navigable in IDE and supplied with proper documentation (#2291).
• CoroutineContext.isActive returns true for contexts without any job in them (#3300).

Bug fixes and improvements

• Kotlin version is updated to 1.8.10.
• JPMS is supported (#2237). Thanks @lion7!
• BroadcastChannel and all the corresponding API are deprecated (#2680).
• Added all supported K/N targets (#3601, #812, #855).
• K/N Dispatchers.Default is backed by the number of threads equal to the number of available cores (#3366).
• Fixed an issue where some coroutines' internal exceptions were not properly serializable (#3328).
• Introduced Job.parent API (#3201).
• Fixed a bug when TestScheduler leaked cancelled jobs (#3398).
• TestScope.timeSource now provides comparable time marks (#3617). Thanks @hfhbd!
• Fixed an issue when cancelled withTimeout handles were preserved in JS runtime (#3440).
• Ensure awaitFrame only awaits a single frame when used from the main looper (#3432). Thanks @pablobaxter!
• Obsolete Class-Path attribute was removed from kotlinx-coroutines-debug.jar manifest (#3361).
• Fixed a bug when updateThreadContext operated on the parent context (#3411).
• Added new Flow.filterIsInstance extension (#3240).
• Dispatchers.Default thread name prefixes are now configurable with system property (#3231).
• Added Flow.timeout operator as @FlowPreview (#2624). Thanks @pablobaxter!
• Improved the performance of the future builder in case of exceptions (#3475). Thanks @He-Pin!
• Mono.awaitSingleOrNull now waits for the onComplete signal (#3487).
• Channel.isClosedForSend and Channel.isClosedForReceive are promoted from experimental to delicate (#3448).
• Fixed a data race in native EventLoop (#3547).
• Dispatchers.IO.limitedParallelism(valueLargerThanIOSize) no longer creates an additional wrapper (#3442). Thanks @dovchinnikov!
• Various @FlowPreview and @ExperimentalCoroutinesApi are promoted to experimental and stable respectively (#3542, #3097, #3548).
• Performance improvements in Dispatchers.Default and Dispatchers.IO (#3416, #3418).
• Fixed a bug when internal suspendCancellableCoroutineReusable might have hanged (#3613).
• Introduced internal API to process events in the current system dispatcher (#3439).
• Global CoroutineExceptionHandler is no longer invoked in case of unprocessed future failure (#3452).
• Performance improvements and reduced thread-local pressure for the withContext operator (#3592).
• Improved performance of DebugProbes (#3527).
• Fixed a bug when the coroutine debugger might have detected the state of a coroutine incorrectly (#3193).
• Various documentation improvements and fixes.

1.6.4

• Added TestScope.backgroundScope for launching coroutines that perform work in the background and need to be cancelled at the end of the test (#3287).
• Fixed the POM of kotlinx-coroutines-debug having an incorrect reference to kotlinx-coroutines-bom, which cause the builds of Maven projects using the debug module to break (#3334).
• Fixed the Publisher.await functions in kotlinx-coroutines-reactive not ensuring that the Subscriber methods are invoked serially (#3360). Thank you, @EgorKulbachka!
• Fixed a memory leak in withTimeout on K/N with the new memory model (#3351).
• Added the guarantee that all Throwable implementations in the core library are serializable (#3328).
• Moved the documentation to https://kotlinlang.org/api/kotlinx.coroutines/ (#3342).
• Various documentation improvements.

1.6.3

• Updated atomicfu version to 0.17.3 (#3321), fixing the projects using this library with JS IR failing to build (#3305).

1.6.2

• Fixed a bug with ThreadLocalElement not being correctly updated when the most outer suspend function was called directly without kotlinx.coroutines (#2930).
• Fixed multiple data races: one that might have been affecting runBlocking event loop, and a benign data race in Mutex (#3250, #3251).
• Obsolete TestCoroutineContext is removed, which fixes the kotlinx-coroutines-test JPMS package being split between kotlinx-coroutines-core and kotlinx-coroutines-test (#3218).
• Updated the ProGuard rules to further shrink the size of the resulting DEX file with coroutines (#3111, #3263). Thanks, @agrieve!
• Atomicfu is updated to 0.17.2, which includes a more efficient and robust JS IR transformer (#3255).
• Kotlin is updated to 1.6.21, Gradle version is updated to 7.4.2 (#3281). Thanks, @wojtek-kalicinski!
• Various documentation improvements.