Collection of updates to SIP-14 (scala.concurrent)

Developed by Viktor Klang and Havoc Pennington

- add Promise.isCompleted

- add Future.successful and Future.failed

- add ExecutionContextExecutor and ExecutionContextExecutorService for Java interop

- remove defaultExecutionContext as default parameter value from promise and future

- add ExecutionContext.Implicits.global which must be explicitly imported, rather
  than the previous always-available value for the implicit EC

- remove currentExecutionContext, since it could create bugs by being
  out of sync with the implicit ExecutionContext

- remove Future task batching (_taskStack) and Future.releaseStack

    This optimization should instead be implemented either in
    a specific thread pool or in a specific ExecutionContext.
    Some pools or ExecutionContexts may not want or need it.
    In this patch, the defaultExecutionContext does not
    keep the batching optimization. Whether it should
    have it should perhaps be determined through benchmarking.

- move internalBlockingCall to BlockContext and remove currentExecutionContext

    In this patch, BlockContext must be implemented by Thread.currentThread,
    so the thread pool is the only place you can add custom hooks
    to be run when blocking.
    We implement BlockContext for the default ForkJoinWorkerThread in terms of
    ForkJoinPool.ManagedBlocker.

- add public BlockContext.current and BlockContext.withBlockContext

    These allow an ExecutionContext or other code to override
    the BlockContext for the current thread. With this
    API, the BlockContext is customizable without
    creating a new pool of threads.

    BlockContext.current is needed to obtain the previous
    BlockContext before you push, so you can "chain up" to
    it if desired.

    BlockContext.withBlockContext is used to override the context
    for a given piece of code.

- move isFutureThrowable into impl.Future

- add implicitNotFound to ExecutionContext

- remove default global EC from future {} and promise {}

- add ExecutionContext.global for explicit use of the global default EC,
  replaces defaultExecutionContext

- add a timeout to scala-concurrent-tck tests that block on SyncVar
  (so tests time out rather than hang)

- insert blocking{} calls into concurrent tck to fix deadlocking

- add NonFatal.apply and tests for NonFatal

- add OnCompleteRunnable marker trait

    This would allow an ExecutionContext to distinguish a Runnable originating
    from Future.onComplete (all callbacks on Future end up going through
    onComplete).

- rename ListenerRunnable to CallbackRunnable and use for KeptPromise too
  Just adds some clarity and consistency.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/library/scala/collection/parallel/TaskSupport.scala b/src/library/scala/collection/parallel/TaskSupport.scala
index 2eaa861429..3d27f619bb 100644
--- a/src/library/scala/collection/parallel/TaskSupport.scala
+++ b/src/library/scala/collection/parallel/TaskSupport.scala
@@ -48,7 +48,7 @@ extends TaskSupport with AdaptiveWorkStealingThreadPoolTasks
  *  By default, parallel collections are parametrized with this task support object, so parallel collections
  *  share the same execution context backend as the rest of the `scala.concurrent` package.
  */
-class ExecutionContextTaskSupport(val environment: ExecutionContext = scala.concurrent.defaultExecutionContext)
+class ExecutionContextTaskSupport(val environment: ExecutionContext = scala.concurrent.ExecutionContext.global)
 extends TaskSupport with ExecutionContextTasks