Don't attempt to prevent certain watch loops

If the managedSources task writes into an unmanaged source directory,
that would cause an infinite loop. I don't think it's worth doing out of
band task execution to try and prevent this.

main/src/main/scala/sbt/Defaults.scala

@@ -379,23 +379,7 @@ object Defaults extends BuildCommon {
       val baseDir = baseDirectory.value
       val bases = unmanagedSourceDirectories.value
       val include = (includeFilter in unmanagedSources).value
-      val exclude = (excludeFilter in unmanagedSources).value match {
-        case e =>
-          val s = state.value
-          try {
-            Project.extract(s).runTask(managedSources in Compile in ThisScope, s) match {
-              case (_, l) if l.nonEmpty =>
-                e || new FileFilter {
-                  private val files = l.toSet
-                  override def accept(pathname: File): Boolean = files.contains(pathname)
-                  override def toString = s"ManagedSourcesFilter($files)"
-                }
-              case _ => e
-            }
-          } catch {
-            case NonFatal(_) => e
-          }
-      }
+      val exclude = (excludeFilter in unmanagedSources).value
       val baseSources =
         if (sourcesInBase.value) Seq(new Source(baseDir, include, exclude, recursive = false))
         else Nil

sbt/src/sbt-test/tests/watch-loop/build.sbt

@@ -1,17 +0,0 @@
-import java.nio.file.Files
-
-lazy val watchLoopTest = taskKey[Unit]("Check that managed sources are filtered")
-
-sourceGenerators in Compile += Def.task {
-  val path = baseDirectory.value.toPath.resolve("src/main/scala/Foo.scala")
-  Files.write(path, "object Foo".getBytes).toFile :: Nil
-}
-
-watchLoopTest := {
-  val watched = watchSources.value
-  val managedSource = (managedSources in Compile).value.head
-  assert(!SourceWrapper.accept(watched, managedSource))
-  assert((sources in Compile).value.foldLeft((true, Set.empty[File])) {
-    case ((res, set), f) => (res && !set.contains(f), set + f)
-  }._1)
-}

sbt/src/sbt-test/tests/watch-loop/project/SourceWrapper.scala

@@ -1,6 +0,0 @@
-package sbt
-
-object SourceWrapper {
-  def accept(sources: Seq[sbt.internal.io.Source], file: File): Boolean =
-    sources.exists(_.accept(file.toPath))
-}

sbt/src/sbt-test/tests/watch-loop/src/main/scala/Bar.scala

@@ -1 +0,0 @@
-object Bar

sbt/src/sbt-test/tests/watch-loop/src/main/scala/Foo.scala

@@ -1 +0,0 @@
-object Foo

sbt/src/sbt-test/tests/watch-loop/test

@@ -1 +0,0 @@
-> watchLoopTest