diff --git a/ivy/src/main/scala/sbt/IvyActions.scala b/ivy/src/main/scala/sbt/IvyActions.scala
index f3ac22c82..0ad3376d3 100644
--- a/ivy/src/main/scala/sbt/IvyActions.scala
+++ b/ivy/src/main/scala/sbt/IvyActions.scala
@@ -16,7 +16,11 @@ import core.resolve.ResolveOptions
 import plugins.resolver.{BasicResolver, DependencyResolver}
 
 final class DeliverConfiguration(val deliverIvyPattern: String, val status: String, val configurations: Option[Seq[Configuration]], val logging: UpdateLogging.Value)
-final class PublishConfiguration(val ivyFile: Option[File], val resolverName: String, val artifacts: Map[Artifact, File], val checksums: Seq[String], val logging: UpdateLogging.Value)
+final class PublishConfiguration(val ivyFile: Option[File], val resolverName: String, val artifacts: Map[Artifact, File], val checksums: Seq[String], val logging: UpdateLogging.Value,
+                                 val overwrite: Boolean) {
+	def this(ivyFile: Option[File], resolverName: String, artifacts: Map[Artifact, File], checksums: Seq[String], logging: UpdateLogging.Value) =
+		this(ivyFile, resolverName, artifacts, checksums, logging, false)
+}
 
 final class UpdateConfiguration(val retrieve: Option[RetrieveConfiguration], val missingOk: Boolean, val logging: UpdateLogging.Value)
 final class RetrieveConfiguration(val retrieveDirectory: File, val outputPattern: String)
@@ -86,11 +90,11 @@ object IvyActions
 		import configuration._
 		module.withModule(log) { case (ivy, md, default) =>
 			val resolver = ivy.getSettings.getResolver(resolverName)
-			if(resolver eq null) error("Undefined resolver '" + resolverName + "'")
+			if(resolver eq null) sys.error("Undefined resolver '" + resolverName + "'")
 			val ivyArtifact = ivyFile map { file => (MDArtifact.newIvyArtifact(md), file) }
 			val cross = crossVersionMap(module.moduleSettings)
-			val as = mapArtifacts(md, cross, artifacts) ++ ivyArtifact.toList
-			withChecksums(resolver, checksums) { publish(md, as, resolver, overwrite = true) }
+			val as = mapArtifacts(md, cross, artifacts) ++ ivyArtifact.toSeq
+			withChecksums(resolver, checksums) { publish(md, as, resolver, overwrite = overwrite) }
 		}
 	}
 	private[this] def withChecksums[T](resolver: DependencyResolver, checksums: Seq[String])(act: => T): T =
diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 9310c44f7..465578606 100755
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -1043,9 +1043,9 @@ object Classpaths
 		makePomConfiguration := new MakePomConfiguration(artifactPath in makePom value, projectInfo.value, None, pomExtra.value, pomPostProcess.value, pomIncludeRepository.value, pomAllRepositories.value),
 		deliverLocalConfiguration := deliverConfig(crossTarget.value, status = if (isSnapshot.value) "integration" else "release", logging = ivyLoggingLevel.value ),
 		deliverConfiguration <<= deliverLocalConfiguration,
-		publishConfiguration := publishConfig(packagedArtifacts.in(publish).value, if(publishMavenStyle.value) None else Some(deliver.value), resolverName = getPublishTo(publishTo.value).name, checksums = checksums.in(publish).value, logging = ivyLoggingLevel.value),
-		publishLocalConfiguration := publishConfig(packagedArtifacts.in(publishLocal).value, Some(deliverLocal.value), checksums.in(publishLocal).value, logging = ivyLoggingLevel.value ),
-		publishM2Configuration := publishConfig(packagedArtifacts.in(publishM2).value, None, resolverName = Resolver.publishMavenLocal.name, checksums = checksums.in(publishM2).value, logging = ivyLoggingLevel.value),
+		publishConfiguration := publishConfig(packagedArtifacts.in(publish).value, if(publishMavenStyle.value) None else Some(deliver.value), resolverName = getPublishTo(publishTo.value).name, checksums = checksums.in(publish).value, logging = ivyLoggingLevel.value, overwrite = isSnapshot.value),
+		publishLocalConfiguration := publishConfig(packagedArtifacts.in(publishLocal).value, Some(deliverLocal.value), checksums.in(publishLocal).value, logging = ivyLoggingLevel.value, overwrite = isSnapshot.value),
+		publishM2Configuration := publishConfig(packagedArtifacts.in(publishM2).value, None, resolverName = Resolver.publishMavenLocal.name, checksums = checksums.in(publishM2).value, logging = ivyLoggingLevel.value, overwrite = isSnapshot.value),
 		ivySbt <<= ivySbt0,
 		ivyModule := { val is = ivySbt.value; new is.Module(moduleSettings.value) },
 		transitiveUpdate <<= transitiveUpdateTask,
@@ -1213,8 +1213,11 @@ object Classpaths
 
 	def deliverConfig(outputDirectory: File, status: String = "release", logging: UpdateLogging.Value = UpdateLogging.DownloadOnly) =
 	    new DeliverConfiguration(deliverPattern(outputDirectory), status, None, logging)
-	def publishConfig(artifacts: Map[Artifact, File], ivyFile: Option[File], checksums: Seq[String], resolverName: String = "local", logging: UpdateLogging.Value = UpdateLogging.DownloadOnly) =
-	    new PublishConfiguration(ivyFile, resolverName, artifacts, checksums, logging)
+	def publishConfig(artifacts: Map[Artifact, File], ivyFile: Option[File], checksums: Seq[String], resolverName: String, logging: UpdateLogging.Value): PublishConfiguration =
+		publishConfig(artifacts, ivyFile, checksums, resolverName, logging, overwrite = false)
+	def publishConfig(artifacts: Map[Artifact, File], ivyFile: Option[File], checksums: Seq[String], resolverName: String = "local", logging: UpdateLogging.Value = UpdateLogging.DownloadOnly, overwrite: Boolean = false) =
+		new PublishConfiguration(ivyFile, resolverName, artifacts, checksums, logging, overwrite)
+
 
 	def deliverPattern(outputPath: File): String  =  (outputPath / "[artifact]-[revision](-[classifier]).[ext]").absolutePath