perf: avoid double checking value0 Future.

He-Pin · He-Pin · commit d8eb98dfcbc8 · 2025-01-04T00:00:21.000+08:00
diff --git a/project/MimaFilters.scala b/project/MimaFilters.scala
@@ -10,6 +10,7 @@ object MimaFilters extends AutoPlugin {
   object autoImport {
     val mimaReferenceVersion = settingKey[Option[String]]("Scala version number to run MiMa against")
   }
+
   import autoImport._
 
   override val globalSettings = Seq(
@@ -41,17 +42,20 @@ object MimaFilters extends AutoPlugin {
 
     // KEEP: the CommonErrors object is not a public API
     ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors"),
-    ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors$")
+    ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors$"),
+
+    //ADD: Await#CompletedFuture is not a public API
+    ProblemFilters.exclude[MissingClassProblem]("scala.concurrent.Await$CompletedFuture$")
   )
 
   override val buildSettings = Seq(
     mimaFailOnNoPrevious := false, // we opt everything out, knowing we only check library/reflect
   )
 
   val mimaSettings: Seq[Setting[_]] = Def.settings(
-    mimaPreviousArtifacts       := mimaReferenceVersion.value.map(organization.value % name.value % _).toSet,
-    mimaCheckDirection          := "both",
-    mimaBinaryIssueFilters     ++= mimaFilters,
-//  mimaReportSignatureProblems := true, // TODO: enable
+    mimaPreviousArtifacts := mimaReferenceVersion.value.map(organization.value % name.value % _).toSet,
+    mimaCheckDirection := "both",
+    mimaBinaryIssueFilters ++= mimaFilters,
+    //  mimaReportSignatureProblems := true, // TODO: enable
   )
 }
diff --git a/src/library/scala/concurrent/package.scala b/src/library/scala/concurrent/package.scala
@@ -125,6 +125,9 @@ package object concurrent {
 }
 
 package concurrent {
+
+  import scala.util.Try
+
   /**
    * This marker trait is used by [[Await]] to ensure that [[Awaitable.ready]] and [[Awaitable.result]]
    * are not directly called by user code. An implicit instance of this trait is only available when
@@ -170,7 +173,7 @@ package concurrent {
     @throws(classOf[TimeoutException])
     @throws(classOf[InterruptedException])
     final def ready[T](awaitable: Awaitable[T], atMost: Duration): awaitable.type = awaitable match {
-      case f: Future[T] if f.isCompleted => awaitable.ready(atMost)(AwaitPermission)
+      case f: Future[T] if f.isCompleted => awaitable
       case _ => blocking(awaitable.ready(atMost)(AwaitPermission))
     }
 
@@ -197,8 +200,12 @@ package concurrent {
     @throws(classOf[TimeoutException])
     @throws(classOf[InterruptedException])
     final def result[T](awaitable: Awaitable[T], atMost: Duration): T = awaitable match {
-      case f: Future[T] if f.isCompleted => f.result(atMost)(AwaitPermission)
+      case CompletedFuture(result: Try[T] @unchecked) => result.get
       case _ => blocking(awaitable.result(atMost)(AwaitPermission))
     }
+
+    private final object CompletedFuture {
+      def unapply[T](f: Future[T]): Option[Try[T]] = f.value
+    }
   }
 }

Original file line number	Diff line number	Diff line change
`@@ -10,6 +10,7 @@ object MimaFilters extends AutoPlugin {`
`10`	`10`	`object autoImport {`
`11`	`11`	`val mimaReferenceVersion = settingKey[Option[String]]("Scala version number to run MiMa against")`
`12`	`12`	`}`
	`13`	`+`
`13`	`14`	`import autoImport._`
`14`	`15`
`15`	`16`	`override val globalSettings = Seq(`
`@@ -41,17 +42,20 @@ object MimaFilters extends AutoPlugin {`
`41`	`42`
`42`	`43`	`// KEEP: the CommonErrors object is not a public API`
`43`	`44`	`ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors"),`
`44`		`- ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors$")`
	`45`	`+ ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors$"),`
	`46`	`+`
	`47`	`+ //ADD: Await#CompletedFuture is not a public API`
	`48`	`+ ProblemFilters.exclude[MissingClassProblem]("scala.concurrent.Await$CompletedFuture$")`
`45`	`49`	`)`
`46`	`50`
`47`	`51`	`override val buildSettings = Seq(`
`48`	`52`	`mimaFailOnNoPrevious := false, // we opt everything out, knowing we only check library/reflect`
`49`	`53`	`)`
`50`	`54`
`51`	`55`	`val mimaSettings: Seq[Setting[_]] = Def.settings(`
`52`		`- mimaPreviousArtifacts := mimaReferenceVersion.value.map(organization.value % name.value % _).toSet,`
`53`		`- mimaCheckDirection := "both",`
`54`		`- mimaBinaryIssueFilters ++= mimaFilters,`
`55`		`-// mimaReportSignatureProblems := true, // TODO: enable`
	`56`	`+ mimaPreviousArtifacts := mimaReferenceVersion.value.map(organization.value % name.value % _).toSet,`
	`57`	`+ mimaCheckDirection := "both",`
	`58`	`+ mimaBinaryIssueFilters ++= mimaFilters,`
	`59`	`+ // mimaReportSignatureProblems := true, // TODO: enable`
`56`	`60`	`)`
`57`	`61`	`}`
Original file line number	Diff line number	Diff line change
`@@ -125,6 +125,9 @@ package object concurrent {`
`125`	`125`	`}`
`126`	`126`
`127`	`127`	`package concurrent {`
	`128`	`+`
	`129`	`+ import scala.util.Try`
	`130`	`+`
`128`	`131`	`/**`
`129`	`132`	`* This marker trait is used by [[Await]] to ensure that [[Awaitable.ready]] and [[Awaitable.result]]`
`130`	`133`	`* are not directly called by user code. An implicit instance of this trait is only available when`
`@@ -170,7 +173,7 @@ package concurrent {`
`170`	`173`	`@throws(classOf[TimeoutException])`
`171`	`174`	`@throws(classOf[InterruptedException])`
`172`	`175`	`final def ready[T](awaitable: Awaitable[T], atMost: Duration): awaitable.type = awaitable match {`
`173`		`- case f: Future[T] if f.isCompleted => awaitable.ready(atMost)(AwaitPermission)`
	`176`	`+ case f: Future[T] if f.isCompleted => awaitable`
`174`	`177`	`case _ => blocking(awaitable.ready(atMost)(AwaitPermission))`
`175`	`178`	`}`
`176`	`179`
`@@ -197,8 +200,12 @@ package concurrent {`
`197`	`200`	`@throws(classOf[TimeoutException])`
`198`	`201`	`@throws(classOf[InterruptedException])`
`199`	`202`	`final def result[T](awaitable: Awaitable[T], atMost: Duration): T = awaitable match {`
`200`		`- case f: Future[T] if f.isCompleted => f.result(atMost)(AwaitPermission)`
	`203`	`+ case CompletedFuture(result: Try[T] @unchecked) => result.get`
`201`	`204`	`case _ => blocking(awaitable.result(atMost)(AwaitPermission))`
`202`	`205`	`}`
	`206`	`+`
	`207`	`+ private final object CompletedFuture {`
	`208`	`+ def unapply[T](f: Future[T]): Option[Try[T]] = f.value`
	`209`	`+ }`
`203`	`210`	`}`
`204`	`211`	`}`