From 82f025bdeca4fc3aad24c814d881634960dcd486 Mon Sep 17 00:00:00 2001
From: Mark Harrah <dmharrah@gmail.com>
Date: Fri, 8 Jul 2011 21:54:59 -0400
Subject: [PATCH] warn when there is an sbt version conflict.  fixes #80

---
 ivy/ConflictWarning.scala  | 20 ++++++++++++++++++++
 ivy/DependencyFilter.scala |  1 +
 ivy/IvyActions.scala       | 12 ++++++++++++
 3 files changed, 33 insertions(+)
 create mode 100644 ivy/ConflictWarning.scala

diff --git a/ivy/ConflictWarning.scala b/ivy/ConflictWarning.scala
new file mode 100644
index 000000000..5d642f04f
--- /dev/null
+++ b/ivy/ConflictWarning.scala
@@ -0,0 +1,20 @@
+package sbt
+
+	import DependencyFilter._
+
+final case class ConflictWarning(filter: ModuleFilter, group: ModuleID => String, level: Level.Value, failOnConflict: Boolean)
+object ConflictWarning
+{
+	def default: ConflictWarning = ConflictWarning( moduleFilter(organization = GlobFilter("org.scala-tools.sbt") | GlobFilter("org.scala-lang")), (_: ModuleID).organization, Level.Warn, false)
+
+	def apply(config: ConflictWarning, report: UpdateReport, log: Logger)
+	{
+		val conflicts = IvyActions.groupedConflicts(config.filter, config.group)(report)
+		if(!conflicts.isEmpty)
+			log.log(config.level, "Potentially incompatible versions specified:")
+		for( (label, versions) <- conflicts )
+			log.log(config.level, "   " + label + ": " + versions.mkString(", "))
+		if(config.failOnConflict && !conflicts.isEmpty)
+			error("Conflicts in " + conflicts.map(_._1).mkString )
+	}
+}
diff --git a/ivy/DependencyFilter.scala b/ivy/DependencyFilter.scala
index 1773525c6..e31cd4e24 100644
--- a/ivy/DependencyFilter.scala
+++ b/ivy/DependencyFilter.scala
@@ -32,6 +32,7 @@ object DependencyFilter extends DependencyFilterExtra
 	implicit def fnToModuleFilter(f: ModuleID => Boolean): ModuleFilter = new ModuleFilter { def apply(m: ModuleID) = f(m) }
 	implicit def fnToArtifactFilter(f: Artifact => Boolean): ArtifactFilter = new ArtifactFilter { def apply(m: Artifact) = f(m) }
 	implicit def fnToConfigurationFilter(f: String => Boolean): ConfigurationFilter = new ConfigurationFilter { def apply(c: String) = f(c) }
+	implicit def subDepFilterToFn[Arg](f: SubDepFilter[Arg, _]): Arg => Boolean = f apply _
 }
 trait DependencyFilter
 {
diff --git a/ivy/IvyActions.scala b/ivy/IvyActions.scala
index eed985a03..ad0f4cdca 100644
--- a/ivy/IvyActions.scala
+++ b/ivy/IvyActions.scala
@@ -131,6 +131,18 @@ object IvyActions
 			}
 		}
 
+	def groupedConflicts[T](moduleFilter: ModuleFilter, grouping: ModuleID => T)(report: UpdateReport): Map[T, Set[String]] =
+		report.configurations.flatMap { confReport =>
+			val evicted = confReport.evicted.filter(moduleFilter)
+			val evictedSet = evicted.map( m => (m.organization, m.name) ).toSet
+			val conflicted = confReport.allModules.filter( mod => evictedSet( (mod.organization, mod.name) ) )
+			grouped(grouping)(conflicted ++ evicted)
+		} toMap;
+
+	def grouped[T](grouping: ModuleID => T)(mods: Seq[ModuleID]): Map[T, Set[String]] =
+		mods groupBy(grouping) mapValues(_.map(_.revision).toSet)
+
+
 	def transitiveScratch(ivySbt: IvySbt, label: String, config: GetClassifiersConfiguration, log: Logger): UpdateReport =
 	{
 			import config.{configuration => c, id, ivyScala, modules => deps}