Keep project selection upon reload.

main/Load.scala

@@ -533,13 +533,18 @@ object Load
 		}
 	}
 
+	def initialSession(structure: BuildStructure, rootEval: () => Eval, s: State): SessionSettings = {
+		val current = s get Keys.sessionSettings map (_.currentProject)
+		new SessionSettings(structure.root, projectMap(structure.units, current), structure.settings, Map.empty, Nil, rootEval)
+	}
+
 	def initialSession(structure: BuildStructure, rootEval: () => Eval): SessionSettings =
-		new SessionSettings(structure.root, rootProjectMap(structure.units), structure.settings, Map.empty, Nil, rootEval)
+		new SessionSettings(structure.root, projectMap(structure.units, None), structure.settings, Map.empty, Nil, rootEval)
 		
-	def rootProjectMap(units: Map[URI, LoadedBuildUnit]): Map[URI, String] =
+	def projectMap(units: Map[URI, LoadedBuildUnit], current: Option[Map[URI, String]]): Map[URI, String] =
 	{
 		val getRoot = getRootProject(units)
-		units.keys.map(uri => (uri, getRoot(uri))).toMap
+		units.keys.map(uri => (uri, current.flatMap(_ get uri) getOrElse getRoot(uri))).toMap
 	}
 
 	def defaultEvalOptions: Seq[String] = Nil

main/Main.scala

@@ -335,8 +335,8 @@ object BuiltinCommands
 		val (s, base) = Project.loadAction(SessionVar.clear(s0), action)
 		IO.createDirectory(base)
 		val (eval, structure) = Load.defaultLoad(s, base, logger(s))
-		val session = Load.initialSession(structure, eval)
+		val session = Load.initialSession(structure, eval, s0)
 		SessionSettings.checkSession(session, s)
 		Project.setProject(session, structure, s)
 	}
-}
+}

sbt/src/sbt-test/actions/reload/project/TestProject.scala

@@ -0,0 +1,11 @@
+import sbt._
+
+object TestBuild extends Build
+{
+	lazy val root = Project("root", file("."), aggregate = Seq(sub)) settings(
+		TaskKey[Unit]("f") := error("f")
+	)
+	lazy val sub = Project("sub", file("sub")) settings(
+		TaskKey[Unit]("f") := {}
+	)
+}

sbt/src/sbt-test/actions/reload/test

@@ -0,0 +1,5 @@
+-> f
+> project sub
+> f
+> reload
+> f