Add some BSP integration tests

bsp/src/mill/bsp/BSP.scala

@@ -75,11 +75,10 @@ object BSP extends ExternalModule with CoursierModule {
   }
 
   private def bspConnectionJson(jobs: Int, debug: Boolean): String = {
-    val props = sys.props
-    val millPath = props
-      .get("mill.main.cli")
+    val millPath = sys.env.get("MILL_MAIN_CLI")
+      .orElse(sys.props.get("mill.main.cli"))
       // we assume, the classpath is an executable jar here
-      .orElse(props.get("java.class.path"))
+      .orElse(sys.props.get("java.class.path"))
       .getOrElse(throw new IllegalStateException("System property 'java.class.path' not set"))
 
     upickle.default.write(

bsp/src/mill/bsp/Constants.scala

@@ -6,6 +6,6 @@ private[mill] object Constants {
   val bspProtocolVersion = BuildInfo.bsp4jVersion
   val bspWorkerImplClass = "mill.bsp.worker.BspWorkerImpl"
   val bspWorkerBuildInfoClass = "mill.bsp.worker.BuildInfo"
-  val languages: Seq[String] = Seq("scala", "java")
+  val languages: Seq[String] = Seq("java", "scala")
   val serverName = "mill-bsp"
 }

bsp/worker/src/mill/bsp/worker/MillBuildServer.scala

@@ -4,7 +4,7 @@ import ch.epfl.scala.bsp4j
 import ch.epfl.scala.bsp4j._
 import com.google.gson.JsonObject
 import mill.api.{DummyTestReporter, Result, Strict}
-import mill.bsp.BspServerResult
+import mill.bsp.{BspServerResult, Constants}
 import mill.bsp.worker.Utils.{makeBuildTarget, outputPaths, sanitizeUri}
 import mill.define.Segment.Label
 import mill.define.{Args, Discover, ExternalModule, Task}
@@ -33,6 +33,8 @@ private class MillBuildServer(
 ) extends ExternalModule
     with BuildServer {
 
+  import MillBuildServer._
+
   lazy val millDiscover: Discover = Discover[this.type]
 
   private[worker] var cancellator: Boolean => Unit = shutdownBefore => ()
@@ -71,7 +73,7 @@ private class MillBuildServer(
 
       // TODO: scan BspModules and infer their capabilities
 
-      val supportedLangs = Seq("java", "scala").asJava
+      val supportedLangs = Constants.languages.asJava
       val capabilities = new BuildServerCapabilities
 
       capabilities.setBuildTargetChangedProvider(false)
@@ -154,7 +156,7 @@ private class MillBuildServer(
   override def workspaceBuildTargets(): CompletableFuture[WorkspaceBuildTargetsResult] =
     completableTasksWithState(
       "workspaceBuildTargets",
-      targetIds = _.bspModulesById.keySet.toSeq,
+      targetIds = _.bspModulesIdList.map(_._1),
       tasks = { case m: BspModule => m.bspBuildTargetData }
     ) { (ev, state, id, m: BspModule, bspBuildTargetData) =>
       val depsIds = m match {
@@ -252,7 +254,7 @@ private class MillBuildServer(
   override def buildTargetInverseSources(p: InverseSourcesParams)
       : CompletableFuture[InverseSourcesResult] = {
     completable(s"buildtargetInverseSources ${p}") { state =>
-      val tasksEvaluators = state.bspModulesById.iterator.collect {
+      val tasksEvaluators = state.bspModulesIdList.iterator.collect {
         case (id, (m: JavaModule, ev)) =>
           Task.Anon {
             val src = m.allSourceFiles()
@@ -263,11 +265,9 @@ private class MillBuildServer(
           } -> ev
       }.toSeq
 
-      val ids = tasksEvaluators
-        .groupMap(_._2)(_._1)
+      val ids = groupList(tasksEvaluators)(_._2)(_._1)
         .flatMap { case (ev, ts) => ev.evalOrThrow()(ts) }
         .flatten
-        .toSeq
 
       new InverseSourcesResult(ids.asJava)
     }
@@ -641,9 +641,8 @@ private class MillBuildServer(
         tasks.lift.apply(m).map(ts => (ts, (ev, id)))
       }
 
-      val evaluated = tasksSeq
-        // group by evaluator (different root module)
-        .groupMap(_._2)(_._1)
+      // group by evaluator (different root module)
+      val evaluated = groupList(tasksSeq.toSeq)(_._2)(_._1)
         .map { case ((ev, id), ts) =>
           val results = ev.evaluate(ts)
           val failures = results.results.collect {
@@ -674,7 +673,7 @@ private class MillBuildServer(
             }
         }
 
-      agg(evaluated.flatten.toSeq.asJava, state)
+      agg(evaluated.flatten.asJava, state)
     }
   }
 
@@ -772,3 +771,17 @@ private class MillBuildServer(
     debug("onRunReadStdin is current unsupported")
   }
 }
+
+private object MillBuildServer {
+
+  /**
+   * Same as Iterable.groupMap, but returns a sequence instead of a map, and preserves
+   * the order of appearance of the keys from the input sequence
+   */
+  private def groupList[A, K, B](seq: Seq[A])(key: A => K)(f: A => B): Seq[(K, Seq[B])] = {
+    val keyIndices = seq.map(key).distinct.zipWithIndex.toMap
+    seq.groupMap(key)(f)
+      .toSeq
+      .sortBy { case (k, _) => keyIndices(k) }
+  }
+}

bsp/worker/src/mill/bsp/worker/State.scala

@@ -7,13 +7,13 @@ import mill.define.Module
 import mill.eval.Evaluator
 
 private class State(workspaceDir: os.Path, evaluators: Seq[Evaluator], debug: String => Unit) {
-  lazy val bspModulesById: Map[BuildTargetIdentifier, (BspModule, Evaluator)] = {
+  lazy val bspModulesIdList: Seq[(BuildTargetIdentifier, (BspModule, Evaluator))] = {
     val modules: Seq[(Module, Seq[Module], Evaluator)] = evaluators
       .map(ev => (ev.rootModule, JavaModuleUtils.transitiveModules(ev.rootModule), ev))
 
-    val map = modules
-      .flatMap { case (rootModule, otherModules, eval) =>
-        (Seq(rootModule) ++ otherModules).collect {
+    modules
+      .flatMap { case (rootModule, modules, eval) =>
+        modules.collect {
           case m: BspModule =>
             val uri = Utils.sanitizeUri(
               rootModule.millSourcePath /
@@ -24,9 +24,10 @@ private class State(workspaceDir: os.Path, evaluators: Seq[Evaluator], debug: St
             (new BuildTargetIdentifier(uri), (m, eval))
         }
       }
-      .toMap
+  }
+  lazy val bspModulesById: Map[BuildTargetIdentifier, (BspModule, Evaluator)] = {
+    val map = bspModulesIdList.toMap
     debug(s"BspModules: ${map.view.mapValues(_._1.bspDisplayName).toMap}")
-
     map
   }
 

bsp/worker/src/mill/bsp/worker/SyntheticRootBspBuildTargetData.scala

@@ -5,7 +5,6 @@ import mill.bsp.worker.Utils.{makeBuildTarget, sanitizeUri}
 import mill.scalalib.bsp.{BspBuildTarget, BspModule}
 import mill.scalalib.bsp.BspModule.Tag
 
-import java.util.UUID
 import scala.jdk.CollectionConverters._
 import ch.epfl.scala.bsp4j.BuildTarget
 
@@ -15,11 +14,11 @@ import ch.epfl.scala.bsp4j.BuildTarget
  */
 class SyntheticRootBspBuildTargetData(topLevelProjectRoot: os.Path) {
   val id: BuildTargetIdentifier = new BuildTargetIdentifier(
-    Utils.sanitizeUri(topLevelProjectRoot / s"synth-build-target-${UUID.randomUUID()}")
+    Utils.sanitizeUri(topLevelProjectRoot / "mill-synthetic-root-target")
   )
 
   val bt: BspBuildTarget = BspBuildTarget(
-    displayName = Some(topLevelProjectRoot.last + "-root"),
+    displayName = Some("mill-synthetic-root"),
     baseDirectory = Some(topLevelProjectRoot),
     tags = Seq(Tag.Manual),
     languageIds = Seq.empty,

integration/ide/bsp-server/resources/project/build.mill

@@ -0,0 +1,10 @@
+package build
+
+import mill._
+import mill.scalalib._
+
+object `hello-java` extends JavaModule
+
+object `hello-scala` extends ScalaModule {
+  def scalaVersion = Option(System.getenv("TEST_SCALA_2_13_VERSION")).getOrElse(???)
+}

integration/ide/bsp-server/resources/snapshots/build-targets-compile-classpaths.json

@@ -0,0 +1,21 @@
+{
+  "items": [
+    {
+      "target": {
+        "uri": "file:///workspace/hello-java"
+      },
+      "classpath": [
+        "file:///workspace/hello-java/compile-resources"
+      ]
+    },
+    {
+      "target": {
+        "uri": "file:///workspace/hello-scala"
+      },
+      "classpath": [
+        "file:///coursier-cache/https/repo1.maven.org/maven2/org/scala-lang/scala-library/<scala-version>/scala-library-<scala-version>.jar",
+        "file:///workspace/hello-scala/compile-resources"
+      ]
+    }
+  ]
+}

integration/ide/bsp-server/resources/snapshots/build-targets-dependency-modules.json

@@ -0,0 +1,21 @@
+{
+  "items": [
+    {
+      "target": {
+        "uri": "file:///workspace/hello-java"
+      },
+      "modules": []
+    },
+    {
+      "target": {
+        "uri": "file:///workspace/hello-scala"
+      },
+      "modules": [
+        {
+          "name": "org.scala-lang:scala-library",
+          "version": "<scala-version>"
+        }
+      ]
+    }
+  ]
+}

integration/ide/bsp-server/resources/snapshots/build-targets-dependency-sources.json

@@ -0,0 +1,18 @@
+{
+  "items": [
+    {
+      "target": {
+        "uri": "file:///workspace/hello-java"
+      },
+      "sources": []
+    },
+    {
+      "target": {
+        "uri": "file:///workspace/hello-scala"
+      },
+      "sources": [
+        "file:///coursier-cache/https/repo1.maven.org/maven2/org/scala-lang/scala-library/<scala-version>/scala-library-<scala-version>-sources.jar"
+      ]
+    }
+  ]
+}

integration/ide/bsp-server/resources/snapshots/build-targets-javac-options.json

@@ -0,0 +1,25 @@
+{
+  "items": [
+    {
+      "target": {
+        "uri": "file:///workspace/hello-java"
+      },
+      "options": [],
+      "classpath": [
+        "file:///workspace/hello-java/compile-resources"
+      ],
+      "classDirectory": "file:///workspace/out/hello-java/compile.dest/classes"
+    },
+    {
+      "target": {
+        "uri": "file:///workspace/hello-scala"
+      },
+      "options": [],
+      "classpath": [
+        "file:///coursier-cache/https/repo1.maven.org/maven2/org/scala-lang/scala-library/<scala-version>/scala-library-<scala-version>.jar",
+        "file:///workspace/hello-scala/compile-resources"
+      ],
+      "classDirectory": "file:///workspace/out/hello-scala/compile.dest/classes"
+    }
+  ]
+}

integration/ide/bsp-server/resources/snapshots/build-targets-jvm-run-environments.json

@@ -0,0 +1,33 @@
+{
+  "items": [
+    {
+      "target": {
+        "uri": "file:///workspace/hello-java"
+      },
+      "classpath": [
+        "file:///workspace/hello-java/compile-resources",
+        "file:///workspace/hello-java/resources",
+        "file:///workspace/out/hello-java/compile.dest/classes"
+      ],
+      "jvmOptions": [],
+      "workingDirectory": "/workspace",
+      "environmentVariables": {},
+      "mainClasses": []
+    },
+    {
+      "target": {
+        "uri": "file:///workspace/hello-scala"
+      },
+      "classpath": [
+        "file:///coursier-cache/https/repo1.maven.org/maven2/org/scala-lang/scala-library/<scala-version>/scala-library-<scala-version>.jar",
+        "file:///workspace/hello-scala/compile-resources",
+        "file:///workspace/hello-scala/resources",
+        "file:///workspace/out/hello-scala/compile.dest/classes"
+      ],
+      "jvmOptions": [],
+      "workingDirectory": "/workspace",
+      "environmentVariables": {},
+      "mainClasses": []
+    }
+  ]
+}

integration/ide/bsp-server/resources/snapshots/build-targets-jvm-test-environments.json

@@ -0,0 +1,33 @@
+{
+  "items": [
+    {
+      "target": {
+        "uri": "file:///workspace/hello-java"
+      },
+      "classpath": [
+        "file:///workspace/hello-java/compile-resources",
+        "file:///workspace/hello-java/resources",
+        "file:///workspace/out/hello-java/compile.dest/classes"
+      ],
+      "jvmOptions": [],
+      "workingDirectory": "/workspace",
+      "environmentVariables": {},
+      "mainClasses": []
+    },
+    {
+      "target": {
+        "uri": "file:///workspace/hello-scala"
+      },
+      "classpath": [
+        "file:///coursier-cache/https/repo1.maven.org/maven2/org/scala-lang/scala-library/<scala-version>/scala-library-<scala-version>.jar",
+        "file:///workspace/hello-scala/compile-resources",
+        "file:///workspace/hello-scala/resources",
+        "file:///workspace/out/hello-scala/compile.dest/classes"
+      ],
+      "jvmOptions": [],
+      "workingDirectory": "/workspace",
+      "environmentVariables": {},
+      "mainClasses": []
+    }
+  ]
+}