Part 13 - fix contrib.playlib resolution of twirl and router worker

Author: bishabosha

contrib/playlib/src/mill/playlib/PlayModule.scala

@@ -26,6 +26,18 @@ trait PlayApiModule extends Dependencies with Router with Server {
 
 }
 trait PlayModule extends PlayApiModule with Static with Twirl {
+  override def twirlScalaVersion: T[String] = Task {
+    if scalaVersion().startsWith("2.13.") then
+      // TODO: This determines which version of `twirl-compiler` library
+      // will be used to source-generate scala files from twirl sources,
+      // which will then be further compiled by the Scala compiler corresponding to `scalaVersion`.
+      // The Scala 3 version of `twirl-compiler` generates code that
+      // is not source compatible with scala 2 - so we should downgrade it to 2.13 version.
+      mill.main.BuildInfo.workerScalaVersion213
+    else
+      super.twirlScalaVersion()
+  }
+
   override def twirlVersion: T[String] = Task {
     playMinorVersion() match {
       case "2.6" => "1.3.16"

contrib/playlib/src/mill/playlib/RouterModule.scala

@@ -80,7 +80,8 @@ trait RouterModule extends ScalaModule with Version {
       repositoriesTask(),
       artifactSuffix = playMinorVersion() match {
         case "2.6" => "_2.12"
-        case _ => "_2.13"
+        case "2.7" | "2.8" => "_2.13"
+        case _ => "_3"
       }
     )
   }

contrib/playlib/test/src/mill/playlib/RouterModuleTests.scala

@@ -71,7 +71,7 @@ object RouterModuleTests extends TestSuite with PlayTestSuite {
             val eitherResult = eval.apply(project.compileRouter)
             val Left(Failure(message, x)) = eitherResult
             val playExpectedMessage =
-              if (playVersion.startsWith("2.6.")) {
+              if !playVersion.startsWith("2.7.") && !playVersion.startsWith("2.8.") then {
                 "HTTP Verb (GET, POST, ...), include (->), comment (#), or modifier line (+) expected"
               } else {
                 "end of input expected"
@@ -98,7 +98,7 @@ object RouterModuleTests extends TestSuite with PlayTestSuite {
             val eitherResult = eval.apply(HelloWorld.core(scalaVersion, playVersion).compileRouter)
             val Left(Failure(message, x)) = eitherResult
             val playExpectedMessage =
-              if (playVersion.startsWith("2.6.")) {
+              if !playVersion.startsWith("2.7.") && !playVersion.startsWith("2.8.") then {
                 "HTTP Verb (GET, POST, ...), include (->), comment (#), or modifier line (+) expected"
               } else {
                 "end of input expected"

contrib/twirllib/src/mill/twirllib/TwirlModule.scala

@@ -20,7 +20,9 @@ trait TwirlModule extends mill.Module { twirlModule =>
    */
   def twirlScalaVersion: T[String] = Task {
     twirlVersion() match {
-      case s"1.$minor.$_" if minor.toIntOption.exists(_ < 4) => BuildInfo.workerScalaVersion212
+      case s"1.$minor.$_" if minor.toIntOption.exists(_ < 6) =>
+        if minor.toIntOption.exists(_ < 4) then BuildInfo.workerScalaVersion212
+        else BuildInfo.workerScalaVersion213
       case _ => BuildInfo.scalaVersion
     }
   }

contrib/twirllib/test/src/mill/twirllib/HelloWorldTests.scala

@@ -7,6 +7,7 @@ import utest.{TestSuite, Tests, assert, _}
 
 trait HelloWorldTests extends TestSuite {
   val testTwirlVersion: String
+  val wildcard: String
 
   trait HelloWorldModule extends mill.twirllib.TwirlModule {
     def twirlVersion = testTwirlVersion
@@ -39,17 +40,17 @@ trait HelloWorldTests extends TestSuite {
   )
 
   def expectedDefaultImports: Seq[String] = Seq(
-    "import _root_.play.twirl.api.TwirlFeatureImports._",
-    "import _root_.play.twirl.api.TwirlHelperImports._",
+    s"import _root_.play.twirl.api.TwirlFeatureImports.$wildcard",
+    s"import _root_.play.twirl.api.TwirlHelperImports.$wildcard",
     "import _root_.play.twirl.api.Html",
     "import _root_.play.twirl.api.JavaScript",
     "import _root_.play.twirl.api.Txt",
     "import _root_.play.twirl.api.Xml"
   )
 
   def testAdditionalImports: Seq[String] = Seq(
-    "mill.twirl.test.AdditionalImport1._",
-    "mill.twirl.test.AdditionalImport2._"
+    s"mill.twirl.test.AdditionalImport1.$wildcard",
+    s"mill.twirl.test.AdditionalImport2.$wildcard"
   )
 
   def testConstructorAnnotations = Seq(
@@ -159,13 +160,17 @@ trait HelloWorldTests extends TestSuite {
 
 object HelloWorldTests1_3 extends HelloWorldTests {
   override val testTwirlVersion = "1.3.16"
+  override val wildcard = "_"
 }
 object HelloWorldTests1_5 extends HelloWorldTests {
   override val testTwirlVersion = "1.5.2"
+  override val wildcard = "_"
 }
 object HelloWorldTests1_6 extends HelloWorldTests {
   override val testTwirlVersion = "1.6.2"
+  override val wildcard = "*"
 }
 object HelloWorldTests2_0 extends HelloWorldTests {
   override val testTwirlVersion = "2.0.1"
+  override val wildcard = "*"
 }

main/package.mill

@@ -25,6 +25,11 @@ object `package` extends RootModule with build.MillStableScalaModule with BuildI
 
   def buildInfoMembers = Seq(
     BuildInfo.Value("scalaVersion", scalaVersion(), "Scala version used to compile mill core."),
+    BuildInfo.Value(
+      "workerScalaVersion213",
+      build.Deps.scala2Version,
+      "Scala 2.13 version used by some workers."
+    ),
     BuildInfo.Value(
       "workerScalaVersion212",
       build.Deps.workerScalaVersion212,