From 273024a238c8ae0f56907e2cf2c4c8498d87317c Mon Sep 17 00:00:00 2001
From: Josh Suereth <joshua.suereth@gmail.com>
Date: Wed, 4 Jun 2014 11:06:49 -0400
Subject: [PATCH] Add special hook to diagnose travis failing test.

---
 .../src/main/scala/sbt/classpath/ClassLoaderCache.scala   | 8 +++++---
 .../src/test/scala/sbt/classpath/ConcurrentCache.scala    | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/util/classpath/src/main/scala/sbt/classpath/ClassLoaderCache.scala b/util/classpath/src/main/scala/sbt/classpath/ClassLoaderCache.scala
index 3886fe4d5..645f45747 100644
--- a/util/classpath/src/main/scala/sbt/classpath/ClassLoaderCache.scala
+++ b/util/classpath/src/main/scala/sbt/classpath/ClassLoaderCache.scala
@@ -5,7 +5,8 @@ import java.io.File
 import java.net.URLClassLoader
 import java.util.HashMap
 
-private[sbt] final class ClassLoaderCache(val commonParent: ClassLoader) {
+// Hack for testing only
+private[sbt] final class ClassLoaderCache(val commonParent: ClassLoader, errorEvicted: Boolean = false) {
   private[this] val delegate = new HashMap[List[File], Reference[CachedClassLoader]]
 
   /**
@@ -25,9 +26,10 @@ private[sbt] final class ClassLoaderCache(val commonParent: ClassLoader) {
       get(files, stamps, existingRef.get)
 
   private[this] def get(files: List[File], stamps: List[Long], existing: CachedClassLoader): ClassLoader =
-    if (existing == null || stamps != existing.timestamps)
+    if (existing == null || stamps != existing.timestamps) {
+      if (existing == null && errorEvicted) sys.error(s"Evicted classloader for [${files mkString ", "}]!!!! Not allowed, Travis!")
       newEntry(files, stamps)
-    else
+    } else
       existing.loader
 
   private[this] def newEntry(files: List[File], stamps: List[Long]): ClassLoader =
diff --git a/util/classpath/src/test/scala/sbt/classpath/ConcurrentCache.scala b/util/classpath/src/test/scala/sbt/classpath/ConcurrentCache.scala
index 8ff943b8d..9ac26af5c 100644
--- a/util/classpath/src/test/scala/sbt/classpath/ConcurrentCache.scala
+++ b/util/classpath/src/test/scala/sbt/classpath/ConcurrentCache.scala
@@ -22,7 +22,7 @@ object ConcurrentCache extends Properties("ClassLoaderCache concurrent access")
 
   property("Same class loader for same classpaths concurrently processed") = forAll { (names: List[String], concurrent: Int) =>
     withcp(names.distinct) { files =>
-      val cache = new ClassLoaderCache(null)
+      val cache = new ClassLoaderCache(null, errorEvicted = true)
       val loaders = (1 to concurrent).par.map(_ => cache(files)).toList
       loaders match {
         case DifferentClassloader(left, right) => false :| s"${showCp(left)} != ${showCp(right)}"
@@ -32,7 +32,7 @@ object ConcurrentCache extends Properties("ClassLoaderCache concurrent access")
   }
 
   private[this] def withcp[T](names: List[String])(f: List[File] => T): T = IO.withTemporaryDirectory { tmp =>
-    val files = names.map { name =>
+    val files = names.sorted.map { name =>
       val file = new File(tmp, name)
       IO.touch(file)
       file