bugfix: Try to fix Mill flaky test

tests/slow/src/test/scala/tests/mill/MillServerCodeLensSuite.scala

@@ -1,7 +1,5 @@
 package tests.mill
 
-import scala.concurrent.duration.Duration
-
 import scala.meta.internal.metals.ServerCommands
 import scala.meta.internal.metals.{BuildInfo => V}
 
@@ -12,8 +10,10 @@ import tests.MillServerInitializer
 class MillServerCodeLensSuite
     extends BaseCodeLensLspSuite("mill-server-lenses", MillServerInitializer) {
 
-  override def munitTimeout: Duration = Duration("4min")
-
+  /*
+   * There is some flakiness involved, possibly https://github.com/com-lihaoyi/mill/issues/2826
+   * We added some timeouts to make sure the test is correctly retried when fetching lenses.
+   */
   test("run-mill-lens", maxRetry = 3) {
     cleanWorkspace()
     writeLayout(
@@ -30,7 +30,7 @@ class MillServerCodeLensSuite
            |// no test lense as debug is not supported
            |class Foo extends munit.FunSuite {}
            |""".stripMargin,
-        V.scala213,
+        V.scala3,
         V.millVersion,
         includeMunit = true,
       )

tests/unit/src/main/scala/tests/TestingServer.scala

@@ -1034,6 +1034,7 @@ final case class TestingServer(
       filename: String,
       maxRetries: Int = 4,
   ): Future[List[l.CodeLens]] = {
+    Debug.printEnclosing(filename)
     val path = toPath(filename)
     val uri = path.toURI.toString
     val params = new CodeLensParams(new TextDocumentIdentifier(uri))
@@ -1048,9 +1049,18 @@ final case class TestingServer(
     var retries = maxRetries
     val codeLenses = Promise[List[l.CodeLens]]()
     val handler = { refreshCount: Int =>
+      scribe.info(s"Refreshing model for $filename")
       if (refreshCount > 0)
         for {
-          lenses <- fullServer.codeLens(params).asScala.map(_.asScala)
+          lenses <- fullServer
+            .codeLens(params)
+            .asScala
+            .map(_.asScala)
+            .withTimeout(10, util.concurrent.TimeUnit.SECONDS)
+            .recover { _ =>
+              scribe.info(s"Timeout for fetching lenses reached for $filename")
+              Nil
+            }
         } {
           if (lenses.nonEmpty) codeLenses.trySuccess(lenses.toList)
           else if (retries > 0) {
@@ -1072,6 +1082,7 @@ final case class TestingServer(
       // first compilation, to trigger the handler
       _ <- server.compilations.compileFile(path)
       lenses <- codeLenses.future
+        .withTimeout(60, util.concurrent.TimeUnit.SECONDS)
     } yield lenses
   }