Don't force discoveredSbtPlugins when bloopInstall

Adds support to elide `discoveredSbtPlugins` for all sbt versions if
either `bloopInstall` or `bloopGenerate` are under execution.

This makes the process faster (exporting the bloop build takes now 11
seconds!).

build.sbt

@@ -12,7 +12,9 @@ val benchmarkBridge = project
   .disablePlugins(ScriptedPlugin)
   .settings(
     releaseEarly := { () },
-    skip in publish := true
+    skip in publish := true,
+    bloopGenerate in Compile := None,
+    bloopGenerate in Test := None,
   )
 
 /***************************************************************************************************/
@@ -171,18 +173,18 @@ lazy val jsBridge06 = project
   .settings(testSettings)
   .settings(
     name := "bloop-js-bridge-0.6",
+    target := (file("bridges") / "scalajs" / "target" / "0.6").getAbsoluteFile,
     libraryDependencies += Dependencies.scalaJsTools06
   )
 
 lazy val jsBridge10 = project
   .dependsOn(frontend % Provided, frontend % "test->test")
-  .in(file("bridges") / "scalajs" / "target" / "scalajs-1.0")
+  .in(file("bridges") / "scalajs")
   .disablePlugins(ScriptedPlugin)
   .settings(testSettings)
   .settings(
     name := "bloop-js-bridge-1.0",
-    sourceDirectories in Compile += file("bridges") / "scalajs" / "src" / "main" / "scala",
-    sourceDirectories in Test += file("bridges") / "scalajs" / "src" / "test" / "scala",
+    target := (file("bridges") / "scalajs" / "target" / "1.0").getAbsoluteFile,
     libraryDependencies += Dependencies.scalaJsTools10
   )
 

integrations/sbt-bloop/src/main/scala-sbt-0.13/bloop/integrations/sbt/Compat.scala

@@ -12,6 +12,8 @@ object Compat {
 
   implicit def fileToRichFile(file: File): sbt.RichFile = new sbt.RichFile(file)
 
+  def currentCommandFromState(s: sbt.State): Option[String] = Some(s.history.current)
+
   def generateCacheFile(s: sbt.Keys.TaskStreams, id: String) = s.cacheDirectory / id
 
   def toBloopArtifact(a: Artifact, f: File): Config.Artifact = {

integrations/sbt-bloop/src/main/scala-sbt-1.0/bloop/integrations/sbt/Compat.scala

@@ -15,6 +15,9 @@ object Compat {
     def ivyScala: SettingKey[Option[ScalaModuleInfo]] = keys.scalaModuleInfo
   }
 
+  def currentCommandFromState(s: sbt.State): Option[String] =
+    s.currentCommand.map(_.commandLine)
+
   implicit def execToString(e: Exec): String = e.commandLine
 
   implicit def fileToRichFile(file: File): sbt.RichFile = new sbt.RichFile(file)

integrations/sbt-bloop/src/main/scala/bloop/integrations/sbt/SbtBloop.scala

@@ -133,7 +133,7 @@ object BloopDefaults {
       BloopKeys.bloopResourceManaged := BloopKeys.bloopTargetDir.value / "resource_managed",
       BloopKeys.bloopGenerate := bloopGenerate.value,
       BloopKeys.bloopAnalysisOut := None
-    ) ++ DiscoveredSbtPlugins.settings
+    ) ++ discoveredSbtPluginsSettings
 
   lazy val projectSettings: Seq[Def.Setting[_]] = {
     sbt.inConfig(Compile)(configSettings) ++
@@ -161,6 +161,29 @@ object BloopDefaults {
       )
   }
 
+  /**
+    * Replace the implementation of discovered sbt plugins so that we don't run it
+    * when we `bloopGenerate` or `bloopInstall`. This is important because when there
+    * are sbt plugins in the build they trigger the compilation of all the modules.
+    * We do no-op when there is indeed an sbt plugin in the build. */
+  lazy val discoveredSbtPluginsSettings: Seq[Def.Setting[_]] = List(
+    Keys.discoveredSbtPlugins := (Def.taskDyn {
+      if (Keys.sbtPlugin.value) Def.task(PluginDiscovery.emptyDiscoveredNames)
+      else {
+        currentCommandFromState(Keys.state.value) match {
+          case Some(userCommand) =>
+            if (userCommand.endsWith(BloopKeys.bloopGenerate.key.label) ||
+              userCommand.endsWith(BloopKeys.bloopInstall.key.label)) {
+              Def.task(PluginDiscovery.emptyDiscoveredNames)
+            } else {
+              Def.task(PluginDiscovery.discoverSourceAll(Keys.compile.value))
+            }
+          case None => Def.task(PluginDiscovery.discoverSourceAll(Keys.compile.value))
+        }
+      }
+    }).value
+  )
+
   private final val ScalaNativePluginLabel = "scala.scalanative.sbtplugin.ScalaNativePlugin"
   private final val ScalaJsPluginLabel = "org.scalajs.sbtplugin.ScalaJSPlugin"
 

project/BuildPlugin.scala

@@ -13,8 +13,8 @@ import sbt.librarymanagement.syntax.stringToOrganization
 import sbt.util.FileFunction
 import sbtassembly.PathList
 import sbtdynver.GitDescribeOutput
-
 import ch.epfl.scala.sbt.release.ReleaseEarlyPlugin.{autoImport => ReleaseEarlyKeys}
+import sbt.internal.PluginDiscovery
 
 object BuildPlugin extends AutoPlugin {
   import sbt.plugins.JvmPlugin

project/MavenPluginIntegration.scala

@@ -97,7 +97,11 @@ object MavenPluginImplementation {
     }
 
     val resourceGenerators: Def.Initialize[Task[Seq[File]]] = Def.taskDyn {
-      if (!MavenPluginKeys.mavenPlugin.value) Def.task(Nil)
+      // Let's protect this so that we don't run it when we do `bloopInstall`
+      val state = Keys.state.value.currentCommand
+      val isBloopInstall = state.exists(e =>
+        e.commandLine.contains("bloopInstall") || e.commandLine.contains("bloopGenerate"))
+      if (!MavenPluginKeys.mavenPlugin.value || isBloopInstall) Def.task(Nil)
       else {
         val task = Def.task {
           val BloopGoal = "bloopInstall"