Better handling of invalid Scala versions

project/build.properties

@@ -1,5 +1,7 @@
+#Project properties
+#Sun Dec 06 21:31:48 EST 2009
 project.organization=org.scala-tools.sbt
 project.name=Simple Build Tool
 sbt.version=0.5.6
-project.version=0.6.5
-scala.version=2.7.5
+project.version=0.6.6
+scala.version=2.7.7

project/plugins/Plugins.scala

@@ -4,6 +4,6 @@ import java.net.URL
 
 class Plugins(info: ProjectInfo) extends PluginDefinition(info)
 {
-	val scripted = "org.scala-tools.sbt" % "test" % "0.6.5"
+	val scripted = "org.scala-tools.sbt" % "test" % "0.6.6"
 	val technically = Resolver.url("technically.us", new URL("http://databinder.net/repo/"))(Resolver.ivyStylePatterns)
 }

scripted/project/build.properties

@@ -3,6 +3,6 @@
 project.organization=org.scala-tools.sbt
 project.name=test
 sbt.version=0.5.6
-project.version=0.6.5
-scala.version=2.7.5
+project.version=0.6.6
+scala.version=2.7.7
 project.initialize=false

src/main/scala/sbt/Main.scala

@@ -155,13 +155,24 @@ class xMain extends xsbti.AppMain
 				case InteractiveCommand :: _ => continue(project, prompt(baseProject, project) :: arguments, interactiveContinue)
 				case SpecificBuild(version, action) :: tail =>
 					if(Some(version) != baseProject.info.buildScalaVersion)
-						throw new ReloadException(rememberCurrent(action :: tail), Some(version))
+					{
+						if(checkVersion(baseProject, version))
+							throw new ReloadException(rememberCurrent(action :: tail), Some(version))
+						else
+							failed(UsageErrorExitCode)
+					}
 					else
 						continue(project, action :: tail, failAction)
 
 				case CrossBuild(action) :: tail =>
 					if(checkAction(project, action))
-						process(project, CrossBuild(project, action) ::: tail, failAction)
+					{
+						CrossBuild(project, action) match
+						{
+							case Some(actions) => continue(project, actions ::: tail, failAction)
+							case None => failed(UsageErrorExitCode)
+						}
+					}
 					else
 						failed(UsageErrorExitCode)
 
@@ -257,21 +268,35 @@ class xMain extends xsbti.AppMain
 				None
 		}
 	}
+	def checkVersion(p: Project, version: String) =
+	{
+		try { p.getScalaInstance(version); true }
+		catch { case e: xsbti.RetrieveException => p.log.error(e.getMessage); false }
+	}
 	object CrossBuild
 	{
 		def unapply(s: String) = if(s.startsWith(CrossBuildPrefix) && !s.startsWith(SpecificBuildPrefix)) Some(s.substring(1)) else None
-		def apply(project: Project, action: String) =
+		def apply(project: Project, action: String): Option[List[String]] =
 		{
 			val againstScalaVersions = project.crossScalaVersions
 			if(againstScalaVersions.isEmpty)
 			{
 				Console.println("Project does not declare any Scala versions to cross-build against, building against current version...")
-				action :: Nil
+				Some(action :: Nil)
 			}
 			else
-				againstScalaVersions.toList.map(SpecificBuildPrefix + _ + " " + action) ::: // build against all versions
-					(SpecificBuildPrefix + project.buildScalaVersion) :: // reset to the version before the cross-build
-					Nil
+			{
+				if( !againstScalaVersions.forall(v => checkVersion(project, v)) )
+					None
+				else
+				{
+					val actions = 
+						againstScalaVersions.toList.map(SpecificBuildPrefix + _ + " " + action) ::: // build against all versions
+							(SpecificBuildPrefix + project.buildScalaVersion) :: // reset to the version before the cross-build
+							Nil
+					Some(actions)
+				}
+			}
 		}
 	}
 	private def readLines(project: Project, file: File): Option[List[String]] =
@@ -382,7 +407,7 @@ class xMain extends xsbti.AppMain
 		printCmd(ShowActions, "Shows all available actions.")
 		printCmd(RebootCommand, "Reloads sbt, picking up modifications to sbt.version or scala.version and recompiling modified project definitions.")
 		printCmd(HelpAction, "Displays this help message.")
-		printCmd(ShowCurrent, "Shows the current project and logging level of that project.")
+		printCmd(ShowCurrent, "Shows the current project, Scala version, and logging level.")
 		printCmd(Level.levels.mkString(", "), "Set logging for the current project to the specified level.")
 		printCmd(TraceCommand, "Toggles whether logging stack traces is enabled.")
 		printCmd(ProjectAction + " <project name>", "Sets the currently active project.")
@@ -408,6 +433,7 @@ class xMain extends xsbti.AppMain
 			case ProjectAction => setProjectError(project.log)
 			case ShowCurrent =>
 				printProject("Current project is ", project)
+				Console.println("Current Scala version is " + project.buildScalaVersion)
 				Console.println("Current log level is " + project.log.getLevel)
 				printTraceEnabled(project)
 				true

src/main/scala/sbt/Project.scala

@@ -227,10 +227,24 @@ trait Project extends TaskManager with Dag[Project] with BasicEnvironment
 	/** The definitive source for the version of Scala being used to *build* the project.*/
 	def buildScalaVersion = info.buildScalaVersion.getOrElse(crossScalaVersions.first)
 
+
 	def componentManager = new xsbt.ComponentManager(info.launcher.globalLock, info.app.components, log)
-	def buildScalaInstance =
-		localScalaInstances.find(_.version == buildScalaVersion) getOrElse
-			xsbt.ScalaInstance(buildScalaVersion, info.launcher)
+	def buildScalaInstance = buildScalaInstance0
+	final def buildScalaInstance0: ScalaInstance =
+	{
+		try { getScalaInstance(buildScalaVersion) }
+		catch { case e: xsbti.RetrieveException if info.buildScalaVersion.isEmpty => // only catch the exception if this is the default Scala version
+			log.error(e.getMessage)
+			SimpleReader.readLine("\nProvide a new Scala version or press enter to exit: ") match
+			{
+				case Some(v) if v.length > 0=> buildScalaVersions() = v; saveEnvironment(); buildScalaInstance0
+				case _ => throw e
+			}
+		}
+	}
+	def getScalaInstance(version: String) =
+		localScalaInstances.find(_.version == version) getOrElse
+			xsbt.ScalaInstance(version, info.launcher)
 	lazy val localScalaInstances: Seq[ScalaInstance] = localScala ++ info.parent.toList.flatMap(_.localScalaInstances)
 	def localScala: Seq[ScalaInstance] = Nil
 	def buildCompiler = new AnalyzingCompiler(buildScalaInstance, componentManager)
@@ -348,12 +362,14 @@ object Project
 			case e: Exception => errorLoadingProject(e, log)
 		}
 	}
-	/** Logs the stack trace and returns an error message in Left.*/
 	private def errorLoadingProject(e: Throwable, log: Logger) =
-	{
-		log.trace(e)
-		new LoadError("Error loading project: " + e.toString)
-	}
+		e match
+		{
+			case _: xsbti.RetrieveException => LoadSetupDeclined
+			case _ =>
+				log.trace(e)
+				new LoadError("Error loading project: " + e.toString)
+		}
 	/** Loads the project for the given `info` and represented by an instance of 'builderClass'.*/
 	private[sbt] def constructProject[P <: Project](info: ProjectInfo, builderClass: Class[P]): P =
 		builderClass.getConstructor(classOf[ProjectInfo]).newInstance(info)