Merge pull request #4443 from eed3si9n/wip/metabuild-classpath

Use the classpath obtained by the launcher for metabuild

main/src/main/scala/sbt/Defaults.scala

@@ -172,6 +172,7 @@ object Defaults extends BuildCommon {
       testForkedParallel :== false,
       javaOptions :== Nil,
       sbtPlugin :== false,
+      isMetaBuild :== false,
       crossPaths :== true,
       sourcePositionMappers :== Nil,
       artifactClassifier in packageSrc :== Some(SourceClassifier),
@@ -1850,11 +1851,19 @@ object Classpaths {
       fullClasspath := concatDistinct(exportedProducts, dependencyClasspath).value,
       internalDependencyClasspath := internalDependencies.value,
       unmanagedClasspath := unmanagedDependencies.value,
-      managedClasspath := managedJars(
-        classpathConfiguration.value,
-        classpathTypes.value,
-        update.value
-      ),
+      managedClasspath := {
+        val isMeta = isMetaBuild.value
+        val app = appConfiguration.value
+        val sbtCp0 = app.provider.mainClasspath.toList
+        val sbtCp = sbtCp0 map { Attributed.blank(_) }
+        val mjars = managedJars(
+          classpathConfiguration.value,
+          classpathTypes.value,
+          update.value
+        )
+        if (isMeta) mjars ++ sbtCp
+        else mjars
+      },
       exportedProducts := trackedExportedProducts(TrackLevel.TrackAlways).value,
       exportedProductsIfMissing := trackedExportedProducts(TrackLevel.TrackIfMissing).value,
       exportedProductsNoTracking := trackedExportedProducts(TrackLevel.NoTracking).value,
@@ -2067,6 +2076,7 @@ object Classpaths {
     allDependencies := {
       projectDependencies.value ++ libraryDependencies.value
     },
+    allExcludeDependencies := excludeDependencies.value,
     scalaModuleInfo := (scalaModuleInfo or (
       Def.setting {
         Option(
@@ -2294,6 +2304,14 @@ object Classpaths {
         ScalaArtifacts.toolDependencies(sbtOrg, version, isDotty) ++ pluginAdjust
       }
     },
+    // in case of meta build, exclude sbt from the dependency graph, so we can use the sbt resolved by the launcher
+    allExcludeDependencies := {
+      val sbtdeps = sbtDependency.value
+      val isMeta = isMetaBuild.value
+      val excludes = excludeDependencies.value
+      if (isMeta) excludes.toVector :+ ExclusionRule(sbtdeps.organization, sbtdeps.name)
+      else excludes
+    },
     dependencyOverrides ++= {
       val isPlugin = sbtPlugin.value
       val app = appConfiguration.value
@@ -2344,7 +2362,7 @@ object Classpaths {
       .withScalaModuleInfo(scalaModuleInfo.value)
       .withDependencies(allDependencies.value.toVector)
       .withOverrides(dependencyOverrides.value.toVector)
-      .withExcludes(excludeDependencies.value.toVector)
+      .withExcludes(allExcludeDependencies.value.toVector)
       .withIvyXML(ivyXML.value)
       .withConfigurations(ivyConfigurations.value.toVector)
       .withDefaultConfiguration(defaultConfiguration.value)

main/src/main/scala/sbt/Keys.scala

@@ -234,6 +234,7 @@ object Keys {
   val classpathOptions = settingKey[ClasspathOptions]("Configures handling of Scala classpaths.").withRank(DSetting)
   val discoveredSbtPlugins = taskKey[PluginDiscovery.DiscoveredNames]("The names of sbt plugin-related modules (modules that extend Build, Plugin, AutoPlugin) defined by this project.").withRank(CTask)
   val sbtPlugin = settingKey[Boolean]("If true, enables adding sbt as a dependency and auto-generation of the plugin descriptor file.").withRank(BMinusSetting)
+  val isMetaBuild = settingKey[Boolean]("If true, this is a metabuild, a project inside project/ directory, and sbt is added to the classpath.").withRank(DSetting)
   val pluginCrossBuild = taskKey[Unit]("Dummy task to scope `sbtVersion in pluginCrossBuild`, which gets used for plugin compilation.")
   val crossSbtVersions = settingKey[Seq[String]]("The versions of Sbt used when cross-building an sbt plugin.")
   val printWarnings = taskKey[Unit]("Shows warnings from compilation, including ones that weren't printed initially.").withRank(BPlusTask)
@@ -454,6 +455,7 @@ object Keys {
   val libraryDependencies = settingKey[Seq[ModuleID]]("Declares managed dependencies.").withRank(APlusSetting)
   val dependencyOverrides = settingKey[Seq[ModuleID]]("Declares managed dependency overrides.").withRank(BSetting)
   val excludeDependencies = settingKey[Seq[InclExclRule]]("Declares managed dependency exclusions.").withRank(BSetting)
+  val allExcludeDependencies = settingKey[Seq[InclExclRule]]("User-defined dependency exclusions and sbt itself in the case of metabuild.").withRank(CTask)
   val allDependencies = taskKey[Seq[ModuleID]]("Inter-project and library dependencies.").withRank(CTask)
   val projectDependencies = taskKey[Seq[ModuleID]]("Inter-project dependencies.").withRank(DTask)
   val ivyXML = settingKey[NodeSeq]("Defines inline Ivy XML for configuring dependency management.").withRank(BSetting)

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

@@ -22,6 +22,7 @@ import Keys.{
   exportedProducts,
   fullClasspath,
   fullResolvers,
+  isMetaBuild,
   loadedBuild,
   onLoadMessage,
   pluginData,
@@ -1180,6 +1181,7 @@ private[sbt] object Load {
   val autoPluginSettings: Seq[Setting[_]] = inScope(GlobalScope in LocalRootProject)(
     Seq(
       sbtPlugin :== true,
+      isMetaBuild :== true,
       pluginData := {
         val prod = (exportedProducts in Configurations.Runtime).value
         val cp = (fullClasspath in Configurations.Runtime).value