Fixes #1869, Ref #1871. Don't enable IvyPlugin for multi project generated root

main/src/main/scala/sbt/Build.scala

@@ -45,7 +45,13 @@ object Build {
   def defaultID(base: File, prefix: String = "default"): String = prefix + "-" + Hash.trimHashString(base.getAbsolutePath, 6)
   @deprecated("Explicitly specify the ID", "0.13.0")
   def defaultProject(base: File): Project = defaultProject(defaultID(base), base)
-  def defaultProject(id: String, base: File): Project = Project(id, base).settings(
+  def defaultProject(id: String, base: File): Project = Project(id, base).settings(defaultProjectSettings: _*)
+  def defaultAggregatedProject(id: String, base: File, agg: Seq[ProjectRef]): Project =
+    defaultProject(id, base).aggregate(agg: _*)
+
+  private[sbt] def generatedRootWithoutIvyPlugin(id: String, base: File, agg: Seq[ProjectRef]): Project =
+    Project.mkGeneratedRoot(id, base, agg).settings(defaultProjectSettings: _*)
+  private[sbt] def defaultProjectSettings: Seq[Setting[_]] = Seq(
     // TODO - Can we move this somewhere else?  ordering of settings is causing this to get borked.
     // if the user has overridden the name, use the normal organization that is derived from the name.
     organization := {
@@ -57,8 +63,6 @@ object Build {
     },
     autoGeneratedProject := true
   )
-  def defaultAggregatedProject(id: String, base: File, agg: Seq[ProjectRef]): Project =
-    defaultProject(id, base).aggregate(agg: _*)
 
   @deprecated("Use Attributed.data", "0.13.0")
   def data[T](in: Seq[Attributed[T]]): Seq[T] = Attributed.data(in)

main/src/main/scala/sbt/BuildStructure.scala

@@ -135,8 +135,21 @@ final class DetectedPlugins(val plugins: DetectedModules[Plugin], val autoPlugin
     }.partition(nonTopLevelPlugin)
 
   /** A function to select the right [[AutoPlugin]]s from [[autoPlugins]] for a [[Project]]. */
+  @deprecated("Use deducePluginsFromProject", "0.13.8")
   lazy val deducePlugins: (Plugins, Logger) => Seq[AutoPlugin] = Plugins.deducer(autoPlugins.toList map { _.value })
 
+  /** Selects the right [[AutoPlugin]]s from a [[Project]]. */
+  def deducePluginsFromProject(p: Project, log: Logger): Seq[AutoPlugin] =
+    {
+      val ps0 = p.plugins
+      val allDetected = autoPlugins.toList map { _.value }
+      val detected = p match {
+        case _: GeneratedRootProject => allDetected filterNot { _ == sbt.plugins.IvyPlugin }
+        case _                       => allDetected
+      }
+      Plugins.deducer(detected)(ps0, log)
+    }
+
   private[this] def autoImports(pluginNames: Seq[String]) = pluginNames.map(_ + ".autoImport")
 
   private[this] def nonTopLevelPlugin(name: String) = name.contains('.')

main/src/main/scala/sbt/Load.scala

@@ -585,9 +585,9 @@ object Load {
               val existingIds = otherProjects.projects map (_.id)
               val refs = existingIds map (id => ProjectRef(buildUri, id))
               val defaultID = autoID(buildBase, context, existingIds)
-              val root1 = Build.defaultAggregatedProject(defaultID, buildBase, refs)
+              val root0 = if (discovered.isEmpty) Build.defaultAggregatedProject(defaultID, buildBase, refs)
-              val root2 = if (discovered.isEmpty) root1 else root1.settings(Keys.publish := (()), Keys.publishLocal := (()))
+              else Build.generatedRootWithoutIvyPlugin(defaultID, buildBase, refs)
-              val root = finalizeProject(root2, files)
+              val root = finalizeProject(root0, files)
               val result = root +: (acc ++ otherProjects.projects)
               log.debug(s"[Loading] Done in ${buildBase}, returning: ${result.map(_.id).mkString("(", ", ", ")")}")
               LoadedProjects(result, generated ++ otherGenerated ++ generatedConfigClassFiles)
@@ -647,7 +647,7 @@ object Load {
       }
     // 2. Discover all the autoplugins and contributed configurations.
     val autoPlugins =
-      try loadedPlugins.detected.deducePlugins(transformedProject.plugins, log)
+      try loadedPlugins.detected.deducePluginsFromProject(transformedProject, log)
       catch { case e: AutoPluginException => throw translateAutoPluginException(e, transformedProject) }
     val autoConfigs = autoPlugins.flatMap(_.projectConfigurations)
 

main/src/main/scala/sbt/Project.scala

@@ -234,6 +234,13 @@ object Project extends ProjectExtra {
     auto: AddSettings = AddSettings.allDefaults): Project =
     unresolved(id, base, aggregate, dependencies, delegates, settings, configurations, auto, Plugins.empty, Nil) // Note: JvmModule/IvyModule auto included...
 
+  /** This is a variation of def apply that mixes in  */
+  private[sbt] def mkGeneratedRoot(id: String, base: File, aggregate: => Seq[ProjectReference]): Project =
+    {
+      validProjectID(id).foreach(errMsg => sys.error("Invalid project ID: " + errMsg))
+      new ProjectDef[ProjectReference](id, base, aggregate, Nil, Nil, Nil, Nil, AddSettings.allDefaults, Plugins.empty, Nil) with Project with GeneratedRootProject
+    }
+
   /** Returns None if `id` is a valid Project ID or Some containing the parser error message if it is not.*/
   def validProjectID(id: String): Option[String] = DefaultParsers.parse(id, DefaultParsers.ID).left.toOption
   private[this] def validProjectIDStart(id: String): Boolean = DefaultParsers.parse(id, DefaultParsers.IDStart).isRight
@@ -571,6 +578,8 @@ object Project extends ProjectExtra {
     }
 }
 
+private[sbt] trait GeneratedRootProject
+
 trait ProjectExtra {
   implicit def configDependencyConstructor[T <% ProjectReference](p: T): Constructor = new Constructor(p)
   implicit def classpathDependency[T <% ProjectReference](p: T): ClasspathDependency = new ClasspathDependency(p, None)

notes/0.13.8.markdown

@@ -74,7 +74,7 @@
 - Fixes eviction warning being too noisy. [#1615][1615] by [@eed3si9n][@eed3si9n]
 - Issues warning if multiple dependencies to a same library is found with different version. [#1634][1634] by [@eed3si9n][@eed3si9n]
 - Removes "No main class detected" warning. [#1766][1766] by [@eed3si9n][@eed3si9n]
-- Disable publishing artificial root by default. [#1871][1871]/[#1869][1869] by [@dwijnand][@dwijnand] 
+- Disable publishing on implicitly created root project by not enabling `IvyPlugin` by default. [#1871][1871]/[#1869][1869] by [@dwijnand][@dwijnand] 
 
 ### Rolling back XML parsing workaround