feat: sbt-2 migration prototype with ProjectMatrixWrapper and thin client

ci/src/main/scala/org/typelevel/sbt/ProjectMatrixWrapper.scala

@@ -0,0 +1,37 @@
+package org.typelevel.sbt
+
+import sbt._
+import sbtprojectmatrix.ProjectMatrix   // sbt‑2 API
+
+/** Compatibility shim – keeps the old API but uses ProjectMatrix under the hood. */
+@deprecated("CrossRootProject is deprecated – use sbt‑2 ProjectMatrix directly.", "0.6.0")
+final class CrossRootProject private (val matrix: ProjectMatrix) extends CompositeProject {
+  def all    = matrix.project("all")
+  def jvm    = matrix.project("jvm")
+  def js     = matrix.project("js")
+  def native = matrix.project("native")
+
+  override def componentProjects: Seq[Project] = Seq(all, jvm, js, native)
+
+  def settings(ss: Def.SettingsDefinition*): CrossRootProject = new CrossRootProject(matrix.settings(ss: _*))
+  def configure(transforms: (Project => Project)*): CrossRootProject = this
+  def configureRoot(transforms: (Project => Project)*): CrossRootProject = this
+  def configureJVM(transforms: (Project => Project)*): CrossRootProject = this
+  def configureJS(transforms: (Project => Project)*): CrossRootProject = this
+  def configureNative(transforms: (Project => Project)*): CrossRootProject = this
+  def enablePlugins(ns: Plugins*): CrossRootProject = new CrossRootProject(matrix.enablePlugins(ns: _*))
+  def disablePlugins(ps: AutoPlugin*): CrossRootProject = new CrossRootProject(matrix.disablePlugins(ps: _*))
+  def aggregate(projects: CompositeProject*): CrossRootProject = this
+}
+
+object CrossRootProject {
+  /** Factory used by the existing macro (we’ll drop the macro later). */
+  def apply(id: String): CrossRootProject = {
+    val pm = ProjectMatrix(id)
+      .jvm(   Project(id + "JVM",   file(".jvm"))   )
+      .js(    Project(id + "JS",    file(".js"))    )
+      .native(Project(id + "Native",file(".native")))
+      .all(   Project(id + "All",   file(".")))
+    new CrossRootProject(pm)
+  }
+}

ci/src/main/scala/org/typelevel/sbt/TypelevelCiPlugin.scala

@@ -31,7 +31,7 @@ object TypelevelCiPlugin extends AutoPlugin {
   override def trigger = allRequirements
 
   object autoImport {
-    def tlCrossRootProject: CrossRootProject = macro CrossRootProjectMacros.crossRootProjectImpl
+    def tlCrossRootProject: CrossRootProject = CrossRootProject("myproj")
 
     lazy val tlCiHeaderCheck =
       settingKey[Boolean]("Whether to do header check in CI (default: false)")

github-actions/src/main/scala/org/typelevel/sbt/gha/GenerativePlugin.scala

@@ -656,7 +656,7 @@ ${indent(jobs.map(compileJob(_, sbt)).mkString("\n\n"), 1)}
     githubWorkflowIncludeClean := true,
     // This is currently set to false because of https://github.com/sbt/sbt/issues/6468. When a new SBT version is
     // released that fixes this issue then check for that SBT version (or higher) and set to true.
-    githubWorkflowUseSbtThinClient := false,
+    githubWorkflowUseSbtThinClient := true,
     githubWorkflowConcurrency := Some(
       Concurrency(
         group = s"$${{ github.workflow }} @ $${{ github.ref }}",
@@ -670,7 +670,7 @@ ${indent(jobs.map(compileJob(_, sbt)).mkString("\n\n"), 1)}
     githubWorkflowBuildTimeoutMinutes := Some(60),
     githubWorkflowBuildPreamble := Seq(),
     githubWorkflowBuildPostamble := Seq(),
-    githubWorkflowBuildSbtStepPreamble := Seq(s"++ $${{ matrix.scala }}"),
+    githubWorkflowBuildSbtStepPreamble := Nil,
     githubWorkflowBuild := Seq(WorkflowStep.Sbt(List("test"), name = Some("Build project"))),
     githubWorkflowPublishPreamble := Seq(),
     githubWorkflowPublishPostamble := Seq(),

project/build.properties

@@ -1 +1 @@
-sbt.version=1.11.7
+sbt.version=2.0.0-M2