bugfix - apply autoImports for global plugins at global configuration stage

Previously, the autoimports for globally defined plugins were not
imported for global configuration files, although they were imported for
project configuration files.

This patch causes an additional plugin discovery phase to happen during
global config evaluation, so that auto-plugins can be detected and their
imports subsequently included.

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

@@ -91,7 +91,10 @@ object Load {
   def buildGlobalSettings(base: File, files: Seq[File], config: sbt.LoadBuildConfiguration): ClassLoader => Seq[Setting[_]] =
     {
       val eval = mkEval(data(config.globalPluginClasspath), base, defaultEvalOptions)
-      val imports = BuildUtil.baseImports ++ BuildUtil.importAllRoot(config.globalPluginNames)
+
+      val imports = BuildUtil.baseImports ++
+        config.detectedGlobalPlugins.imports
+
       loader => {
         val loaded = EvaluateConfigurations(eval, files, imports)(loader)
         // TODO - We have a potential leak of config-classes in the global directory right now.
@@ -718,10 +721,13 @@ object Load {
     loadedPlugins: sbt.LoadedPlugins,
     eval: () => Eval,
     memoSettings: mutable.Map[File, LoadedSbtFile]): DiscoveredProjects = {
+
     // Default sbt files to read, if needed
     lazy val defaultSbtFiles = configurationSources(projectBase)
+
     // Classloader of the build
     val loader = loadedPlugins.loader
+
     // How to load an individual file for use later.
     // TODO - We should import vals defined in other sbt files here, if we wish to
     // share.  For now, build.sbt files have their own unique namespace.
@@ -730,11 +736,13 @@ object Load {
     // How to merge SbtFiles we read into one thing
     def merge(ls: Seq[LoadedSbtFile]): LoadedSbtFile = (LoadedSbtFile.empty /: ls) { _ merge _ }
     // Loads a given file, or pulls from the cache.
+
     def memoLoadSettingsFile(src: File): LoadedSbtFile = memoSettings.getOrElse(src, {
       val lf = loadSettingsFile(src)
       memoSettings.put(src, lf.clearProjects) // don't load projects twice
       lf
     })
+
     // Loads a set of sbt files, sorted by their lexical name (current behavior of sbt).
     def loadFiles(fs: Seq[File]): LoadedSbtFile =
       merge(fs.sortBy(_.getName).map(memoLoadSettingsFile))
@@ -971,6 +979,19 @@ final case class LoadBuildConfiguration(
     log: Logger) {
   lazy val (globalPluginClasspath, globalPluginLoader) = Load.pluginDefinitionLoader(this, Load.globalPluginClasspath(globalPlugin))
   lazy val globalPluginNames = if (globalPluginClasspath.isEmpty) Nil else Load.getPluginNames(globalPluginClasspath, globalPluginLoader)
+
+  private[sbt] lazy val globalPluginDefs = {
+    val pluginData = globalPlugin match {
+      case Some(x) => PluginData(x.data.fullClasspath, x.data.internalClasspath, Some(x.data.resolvers), Some(x.data.updateReport), Nil)
+      case None    => PluginData(globalPluginClasspath, Nil, None, None, Nil)
+    }
+    val baseDir = globalPlugin match {
+      case Some(x) => x.base
+      case _       => stagingDirectory
+    }
+    Load.loadPluginDefinition(baseDir, this, pluginData)
+  }
+  lazy val detectedGlobalPlugins = globalPluginDefs.detected
 }
 
 final class IncompatiblePluginsException(msg: String, cause: Throwable) extends Exception(msg, cause)

notes/0.13.10.markdown

@@ -11,6 +11,7 @@
   [@fkorotkov]: http://github.com/fkorotkov
   [@hgiddens]: https://github.com/hgiddens
   [@DavidPerezIngeniero]: https://github.com/DavidPerezIngeniero
+  [@timcharper]: https://github.com/timcharper
   [2302]: https://github.com/sbt/sbt/issues/2302
   [2303]: https://github.com/sbt/sbt/pull/2303
   [1967]: https://github.com/sbt/sbt/issues/1967
@@ -62,6 +63,8 @@
   [1968]: https://github.com/sbt/sbt/issues/1968
   [2264]: https://github.com/sbt/sbt/issues/2264
   [2172]: https://github.com/sbt/sbt/pull/2172
+  [2120]: https://github.com/sbt/sbt/issues/2120
+  [2399]: https://github.com/sbt/sbt/pull/2399
 
 ### Fixes with compatibility implications
 
@@ -109,6 +112,7 @@
 - Fixes `JavaErrorParser` to parse non-compile-errors [#2256][2256]/[#2272][2272] by [@Duhemm][@Duhemm]
 
 - Fixes task scheduling performance on large builds by skipping checks in `sbt.Execute`. [#2302][2302]/[#2303][2303] by [@jrudolph][@jrudolph]
+- Fixes autoImports for AutoPlugins for global configuration files. [#2120][2120]/[#2399][2399] by [@timcharper][@timcharper]
 
 ### Def.settings
 

sbt/src/sbt-test/project/global-plugin/global/plugins/A.scala

@@ -1,5 +1,15 @@
 package test
 
+import sbt._
+
 object Global {
   val x = 3
 }
+
+object GlobalAutoPlugin extends AutoPlugin {
+
+  object autoImport {
+    lazy val globalAutoPluginSetting = settingKey[String]("A top level setting declared in a plugin.")
+  }
+
+}

sbt/src/sbt-test/project/global-plugin/global/plugins/B.scala

@@ -0,0 +1,7 @@
+import sbt._
+
+object GlobalLegacyPlugin extends sbt.Plugin {
+  import sbt.Keys._
+  val globalLegacyPluginSetting = SettingKey[String]("A top level setting declared by a legacy plugin")
+  val useGlobalLegacyPluginSetting = globalLegacyPluginSetting in Global
+}

sbt/src/sbt-test/project/global-plugin/global/useGlobalAutoPlugin.sbt

@@ -0,0 +1,2 @@
+// If the GlobalAutoPlugin.autoImport._ does not get brought in, this will fail:
+globalAutoPluginSetting := "bar"

sbt/src/sbt-test/project/global-plugin/global/useGlobalLegacyPlugin.sbt

@@ -0,0 +1,5 @@
+/*
+ If the GlobalLegacyPlugin 'in' statements do not register and get
+ brought in to the global scope, this will fail
+ */
+globalLegacyPluginSetting := "foo"