Add -Dsbt.cli.nodelegation option to experiment with no delegation for running/showing tasks/settings from the command line.

With this set to true, the following is no longer allowed for example:

> compile:update

main/src/main/scala/sbt/Act.scala

@@ -263,10 +263,10 @@ object Act
 	def keyValues[T](extracted: Extracted)(keys: Seq[ScopedKey[T]]): Values[T] = keyValues(extracted.structure)(keys)
 	def keyValues[T](structure: BuildStructure)(keys: Seq[ScopedKey[T]]): Values[T] =
 		keys.flatMap { key =>
-			structure.data.get(key.scope, key.key) map { value =>
+			getValue(structure.data, key.scope, key.key) map { value => KeyValue(key, value) }
-				KeyValue(key, value)
-			}
 		}
+	private[this] def getValue[T](data: Settings[Scope], scope: Scope, key: AttributeKey[T]): Option[T] =
+		if(java.lang.Boolean.getBoolean("sbt.cli.nodelegation")) data.getDirect(scope, key) else data.get(scope, key)
 
 	def requireSession[T](s: State, p: => Parser[T]): Parser[T] =
 		if(s get sessionSettings isEmpty) failure("No project loaded") else p

util/collection/src/main/scala/sbt/Settings.scala

@@ -13,6 +13,7 @@ sealed trait Settings[Scope]
 	def definingScope(scope: Scope, key: AttributeKey[_]): Option[Scope]
 	def allKeys[T](f: (Scope, AttributeKey[_]) => T): Seq[T]
 	def get[T](scope: Scope, key: AttributeKey[T]): Option[T]
+	def getDirect[T](scope: Scope, key: AttributeKey[T]): Option[T]
 	def set[T](scope: Scope, key: AttributeKey[T], value: T): Settings[Scope]
 }
 
@@ -23,11 +24,11 @@ private final class Settings0[Scope](val data: Map[Scope, AttributeMap], val del
 	def allKeys[T](f: (Scope, AttributeKey[_]) => T): Seq[T] = data.flatMap { case (scope, map) => map.keys.map(k => f(scope, k)) } toSeq;
 
 	def get[T](scope: Scope, key: AttributeKey[T]): Option[T] =
-		delegates(scope).toStream.flatMap(sc => scopeLocal(sc, key) ).headOption
+		delegates(scope).toStream.flatMap(sc => getDirect(sc, key) ).headOption
 	def definingScope(scope: Scope, key: AttributeKey[_]): Option[Scope] =
-		delegates(scope).toStream.filter(sc => scopeLocal(sc, key).isDefined ).headOption
+		delegates(scope).toStream.filter(sc => getDirect(sc, key).isDefined ).headOption
 
-	private def scopeLocal[T](scope: Scope, key: AttributeKey[T]): Option[T] =
+	def getDirect[T](scope: Scope, key: AttributeKey[T]): Option[T] =
 		(data get scope).flatMap(_ get key)
 
 	def set[T](scope: Scope, key: AttributeKey[T], value: T): Settings[Scope] =
@@ -74,7 +75,7 @@ trait Init[Scope]
 		new Apply[({ type l[L[x]] = List[L[S]] })#l, T](f, inputs.toList, AList.seq[S])
 
 	/** Constructs a derived setting that will be automatically defined in every scope where one of its dependencies
-   * is explicitly defined and the where the scope matches `filter`.
+	* is explicitly defined and the where the scope matches `filter`.
 	* A setting initialized with dynamic dependencies is only allowed if `allowDynamic` is true.
 	* Only the static dependencies are tracked, however. */
 	final def derive[T](s: Setting[T], allowDynamic: Boolean = false, filter: Scope => Boolean = const(true), trigger: AttributeKey[_] => Boolean = const(true)): Setting[T] = {