Commit 8177a0a

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Disallow reconfiguring the executor in newFixedThreadPoolContext (#4364)

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+34

-4

lines changed

+34

-4

lines changed

Lines changed: 1 addition & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -14,5 +14,5 @@ public actual fun newFixedThreadPoolContext(nThreads: Int, name: String): Execut`
`14`	`14`	`t.isDaemon = true`
`15`	`15`	`t`
`16`	`16`	`}`
`17`		`- return executor.asCoroutineDispatcher()`
	`17`	`+ return Executors.unconfigurableExecutorService(executor).asCoroutineDispatcher()`
`18`	`18`	`}`

Lines changed: 30 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,30 @@`
	`1`	`+package kotlinx.coroutines`
	`2`	`+`
	`3`	`+import kotlinx.coroutines.internal.LocalAtomicInt`
	`4`	`+import kotlinx.coroutines.testing.*`
	`5`	`+import java.util.concurrent.ScheduledThreadPoolExecutor`
	`6`	`+import kotlin.coroutines.EmptyCoroutineContext`
	`7`	`+import kotlin.test.*`
	`8`	`+`
	`9`	`+class MultithreadedDispatchersJvmTest: TestBase() {`
	`10`	`+ /** Tests that the executor created in [newFixedThreadPoolContext] can not leak and be reconfigured. */`
	`11`	`+ @Test`
	`12`	`+ fun testExecutorReconfiguration() {`
	`13`	`+ newFixedThreadPoolContext(1, "test").apply {`
	`14`	`+ (executor as? ScheduledThreadPoolExecutor)?.corePoolSize = 2`
	`15`	`+ }.use { ctx ->`
	`16`	`+ val atomicInt = LocalAtomicInt(0)`
	`17`	`+ repeat(100) {`
	`18`	`+ ctx.dispatch(EmptyCoroutineContext, Runnable {`
	`19`	`+ val entered = atomicInt.incrementAndGet()`
	`20`	`+ Thread.yield() // allow other tasks to run`
	`21`	`+ try {`
	`22`	`+ check(entered == 1) { "Expected only one thread to be used, observed $entered" }`
	`23`	`+ } finally {`
	`24`	`+ atomicInt.decrementAndGet()`
	`25`	`+ }`
	`26`	`+ })`
	`27`	`+ }`
	`28`	`+ }`
	`29`	`+ }`
	`30`	`+}`

Lines changed: 0 additions & 3 deletions

Original file line number	Diff line number	Diff line change
`@@ -7,9 +7,6 @@ import kotlin.coroutines.*`
`7`	`7`
`8`	`8`	`internal fun newSingleThreadContext(name: String): ExecutorCoroutineDispatcher = ClosedAfterGuideTestDispatcher(1, name)`
`9`	`9`
`10`		`-internal fun newFixedThreadPoolContext(nThreads: Int, name: String): ExecutorCoroutineDispatcher =`
`11`		`- ClosedAfterGuideTestDispatcher(nThreads, name)`
`12`		`-`
`13`	`10`	`private class ClosedAfterGuideTestDispatcher(`
`14`	`11`	`private val nThreads: Int,`
`15`	`12`	`private val name: String`

Lines changed: 3 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -127,6 +127,9 @@ object FieldWalker {`
`127`	`127`	`element is AtomicLongFieldUpdater<*> -> {`
`128`	`128`	`/* filter it out here to suppress its subclasses too */`
`129`	`129`	`}`
	`130`	`+ element is ExecutorService && type.name == "java.util.concurrent.Executors\$DelegatedExecutorService" -> {`
	`131`	`+ /* can't access anything in the executor */`
	`132`	`+ }`
`130`	`133`	`// All the other classes are reflectively scanned`
`131`	`134`	`else -> fields(type, statics).forEach { field ->`
`132`	`135`	`push(field.get(element), visited, stack) { Ref.FieldRef(element, field.name) }`

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