From e8673866b79f7473391dcee26243eee80d5d3cb6 Mon Sep 17 00:00:00 2001
From: Christopher Vogt <oss.nsp@cvogt.org>
Date: Thu, 9 Feb 2017 21:20:11 -0500
Subject: idempotent change propagation using lastModified instead of a
 non-idempotent needsUpdate flag this fixes a bug where dependees would not be
 rebuilt if cbt exited or was killed after dependencies were already rebuilt.

---
 stage1/cbt.scala | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

(limited to 'stage1/cbt.scala')

diff --git a/stage1/cbt.scala b/stage1/cbt.scala
index 01c9303..0b0ccbf 100644
--- a/stage1/cbt.scala
+++ b/stage1/cbt.scala
@@ -33,6 +33,11 @@ object `package`{
     def ++( s: String ): URL = new URL( url.toString ++ s )
     def string = url.toString
   }
+  implicit class SeqExtensions[T](seq: Seq[T]){
+     def maxOption(implicit ev: Ordering[T]): Option[T] = try{ Some(seq.max) } catch {
+       case e:java.lang.UnsupportedOperationException if e.getMessage === "empty.max" => None
+     }
+  }
   implicit class BuildInterfaceExtensions(build: BuildInterface){
     import build._
     // TODO: if every build has a method triggers a callback if files change
@@ -52,30 +57,30 @@ object `package`{
     def exportedClasspath: ClassPath = ClassPath(exportedClasspathArray.to)
     def classpath = exportedClasspath ++ dependencyClasspath
     def dependencies: Seq[Dependency] = dependenciesArray.to
-    def needsUpdate: Boolean = needsUpdateCompat
   }
   implicit class ContextExtensions(subject: Context){
     import subject._
     val paths = CbtPaths(cbtHome, cache)
     implicit def logger: Logger = new Logger(enabledLoggers, start)
 
-    def classLoaderCache: ClassLoaderCache = new ClassLoaderCache( logger, persistentCache )
-    def cbtDependency = {
+    def classLoaderCache: ClassLoaderCache = new ClassLoaderCache( persistentCache )
+    def cbtDependencies = {
       import paths._
-      new CbtDependency(cbtHasChanged, mavenCache, nailgunTarget, stage1Target, stage2Target, compatibilityTarget)(logger, transientCache)
+      new CbtDependencies(mavenCache, nailgunTarget, stage1Target, stage2Target, compatibilityTarget)(logger, transientCache)
     }
+    val cbtDependency = cbtDependencies.stage2Dependency
+
     def args: Seq[String] = argsArray.to
     def enabledLoggers: Set[String] = enabledLoggersArray.to
     def scalaVersion = Option(scalaVersionOrNull)
     def parentBuild = Option(parentBuildOrNull)
-    def start: scala.Long = startCompat
-    def cbtHasChanged: scala.Boolean = cbtHasChangedCompat
+    def cbtLastModified: scala.Long = subject.cbtLastModified
 
     def copy(
       projectDirectory: File = projectDirectory,
       args: Seq[String] = args,
       //enabledLoggers: Set[String] = enabledLoggers,
-      cbtHasChanged: Boolean = cbtHasChanged,
+      cbtLastModified: Long = cbtLastModified,
       scalaVersion: Option[String] = scalaVersion,
       cbtHome: File = cbtHome,
       parentBuild: Option[BuildInterface] = None
@@ -84,8 +89,8 @@ object `package`{
       cwd,
       args.to,
       enabledLoggers.to,
-      startCompat,
-      cbtHasChangedCompat,
+      start,
+      cbtLastModified,
       scalaVersion.getOrElse(null),
       persistentCache,
       transientCache,
-- 
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