Add bspEnabled setting

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

@@ -386,7 +386,8 @@ object Keys {
   val exportPipelining = settingKey[Boolean]("Product early output so downstream subprojects can do pipelining.").withRank(BSetting)
 
   val bspConfig = taskKey[Unit]("Create or update the BSP connection files").withRank(DSetting)
-  val bspTargetIdentifier = settingKey[BuildTargetIdentifier]("Id for BSP build target.").withRank(DSetting)
+  val bspEnabled = settingKey[Boolean]("Enable/Disable BSP for this build, project or configuration")
+  val bspTargetIdentifier = settingKey[BuildTargetIdentifier]("Build target identifier of a project and configuration.").withRank(DSetting)
   val bspWorkspace = settingKey[Map[BuildTargetIdentifier, Scope]]("Mapping of BSP build targets to sbt scopes").withRank(DSetting)
   val bspInternalDependencyConfigurations = settingKey[Seq[(ProjectRef, Set[ConfigKey])]]("The project configurations that this configuration depends on, possibly transitivly").withRank(DSetting)
   val bspWorkspaceBuildTargets = taskKey[Seq[BuildTarget]]("List all the BSP build targets").withRank(DTask)

main/src/main/scala/sbt/internal/server/BuildServerProtocol.scala

@@ -39,6 +39,7 @@ object BuildServerProtocol {
       sbtVersion.value,
       (ThisBuild / baseDirectory).value
     ),
+    bspEnabled := true,
     bspWorkspace := bspWorkspaceSetting.value,
     bspWorkspaceBuildTargets := Def.taskDyn {
       val workspace = Keys.bspWorkspace.value
@@ -246,7 +247,15 @@ object BuildServerProtocol {
           .map(_ / Keys.bspTargetIdentifier)
           .join
           .value
-        targetIds.zip(scopes).toMap
+        val bspEnabled = scopes
+          .map(_ / Keys.bspEnabled)
+          .join
+          .value
+        val result = for {
+          (targetId, scope, bspEnabled) <- (targetIds, scopes, bspEnabled).zipped
+          if bspEnabled
+        } yield targetId -> scope
+        result.toMap
       }
     }