Add explicit result types for public API (#2955)

Pull request: #2955

bsp/src/mill/bsp/Constants.scala

@@ -1,10 +1,11 @@
 package mill.bsp
 
+import os.SubPath
 private[mill] object Constants {
-  val bspDir = os.sub / ".bsp"
+  val bspDir: SubPath = os.sub / ".bsp"
   val bspProtocolVersion = BuildInfo.bsp4jVersion
   val bspWorkerImplClass = "mill.bsp.worker.BspWorkerImpl"
   val bspWorkerBuildInfoClass = "mill.bsp.worker.BuildInfo"
-  val languages = Seq("scala", "java")
+  val languages: Seq[String] = Seq("scala", "java")
   val serverName = "mill-bsp"
 }

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

@@ -86,7 +86,7 @@ private class MillBuildServer(
 ) extends ExternalModule
     with BuildServer {
 
-  lazy val millDiscover: Discover[MillBuildServer.this.type] = Discover[this.type]
+  lazy val millDiscover: Discover[this.type] = Discover[this.type]
 
   private[worker] var cancellator: Boolean => Unit = shutdownBefore => ()
   private[worker] var onSessionEnd: Option[BspServerResult => Unit] = None
@@ -108,7 +108,7 @@ private class MillBuildServer(
     }
   }
 
-  def debug(msg: String) = logStream.println(msg)
+  def debug(msg: String): Unit = logStream.println(msg)
 
   def onConnectWithClient(buildClient: BuildClient): Unit = client = buildClient
 

contrib/artifactory/src/mill/contrib/artifactory/ArtifactoryHttpApi.scala

@@ -3,13 +3,14 @@ package mill.contrib.artifactory
 import java.util.Base64
 
 import scala.concurrent.duration._
+import requests.Session
 
 class ArtifactoryHttpApi(
     credentials: String,
     readTimeout: Int,
     connectTimeout: Int
 ) {
-  val http = requests.Session(
+  val http: Session = requests.Session(
     readTimeout = readTimeout,
     connectTimeout = connectTimeout,
     maxRedirects = 0,

contrib/bintray/src/mill/contrib/bintray/BintrayHttpApi.scala

@@ -7,6 +7,7 @@ import java.time.format.DateTimeFormatter
 import java.util.Base64
 
 import scala.concurrent.duration._
+import requests.Session
 
 class BintrayHttpApi(
     owner: String,
@@ -16,7 +17,7 @@ class BintrayHttpApi(
     connectTimeout: Int,
     log: Logger
 ) {
-  val http = requests.Session(
+  val http: Session = requests.Session(
     readTimeout = readTimeout,
     connectTimeout = connectTimeout,
     maxRedirects = 0,
@@ -25,7 +26,7 @@ class BintrayHttpApi(
 
   private val uploadTimeout = 5.minutes.toMillis.toInt
 
-  def now = ZonedDateTime.now(ZoneOffset.UTC)
+  def now: ZonedDateTime = ZonedDateTime.now(ZoneOffset.UTC)
 
   // https://www.jfrog.com/confluence/display/BT/Bintray+REST+API#BintrayRESTAPI-UploadContent
   def upload(
@@ -90,9 +91,10 @@ class BintrayHttpApi(
 
   object Paths {
     val root = "https://api.bintray.com"
-    def upload(pkg: String, version: String) = s"$root/content/$owner/$repo/$pkg/$version"
-    def publish(pkg: String, version: String) = s"$root/content/$owner/$repo/$pkg/$version/publish"
-    def version(pkg: String) = s"$root/packages/$owner/$repo/$pkg/versions"
+    def upload(pkg: String, version: String): String = s"$root/content/$owner/$repo/$pkg/$version"
+    def publish(pkg: String, version: String): String =
+      s"$root/content/$owner/$repo/$pkg/$version/publish"
+    def version(pkg: String): String = s"$root/packages/$owner/$repo/$pkg/versions"
   }
 
   object ContentTypes {
@@ -102,7 +104,7 @@ class BintrayHttpApi(
   }
 
   object Auth {
-    val basic = s"Basic ${base64(credentials)}"
+    val basic: String = s"Basic ${base64(credentials)}"
   }
 
   private def base64(s: String) =

contrib/bintray/src/mill/contrib/bintray/BintrayPublisher.scala

@@ -21,8 +21,8 @@ class BintrayPublisher(
     log
   )
 
-  def publish(publishData: BintrayPublishData) = publishAll(publishData)
-  def publishAll(publishData: BintrayPublishData*) = {
+  def publish(publishData: BintrayPublishData): Unit = publishAll(publishData)
+  def publishAll(publishData: BintrayPublishData*): Unit = {
     val mappings =
       for {
         BintrayPublishData(meta, payload, pkg) <- publishData

contrib/bloop/src/mill/contrib/bloop/BloopImpl.scala

@@ -144,7 +144,7 @@ class BloopImpl(ev: () => Evaluator, wd: os.Path) extends ExternalModule { outer
     Result.Success(sources.toMap)
   }
 
-  protected def name(m: JavaModule) = ModuleUtils.moduleDisplayName(m) match {
+  protected def name(m: JavaModule): String = ModuleUtils.moduleDisplayName(m) match {
     case "" => "root-module"
     case n => n
   }
@@ -433,5 +433,5 @@ class BloopImpl(ev: () => Evaluator, wd: os.Path) extends ExternalModule { outer
     }
   }
 
-  lazy val millDiscover = Discover[this.type]
+  lazy val millDiscover: Discover[this.type] = Discover[this.type]
 }

contrib/buildinfo/src/mill/contrib/buildinfo/BuildInfo.scala

@@ -1,6 +1,7 @@
 package mill.contrib.buildinfo
 
-import mill.{PathRef, T}
+import mill.T
+import mill.api.PathRef
 import mill.scalalib.{JavaModule, ScalaModule}
 import mill.scalanativelib.ScalaNativeModule
 import mill.scalajslib.ScalaJSModule
@@ -34,7 +35,7 @@ trait BuildInfo extends JavaModule {
    */
   def buildInfoMembers: T[Seq[BuildInfo.Value]] = Seq.empty[BuildInfo.Value]
 
-  def resources =
+  def resources: T[Seq[PathRef]] =
     if (buildInfoStaticCompiled) super.resources
     else T.sources { super.resources() ++ Seq(buildInfoResources()) }
 
@@ -219,7 +220,7 @@ object BuildInfo {
       """.stripMargin.trim
   }
 
-  def commentStr(v: Value) = {
+  def commentStr(v: Value): String = {
     if (v.comment.isEmpty) ""
     else {
       val lines = v.comment.linesIterator.toVector

contrib/codeartifact/src/mill/contrib/codeartifact/CodeartifactHttpApi.scala

@@ -1,13 +1,14 @@
 package mill.contrib.codeartifact
 
 import scala.concurrent.duration._
+import requests.Session
 
 class CodeartifactHttpApi(
     credentials: String,
     readTimeout: Int,
     connectTimeout: Int
 ) {
-  val http = requests.Session(
+  val http: Session = requests.Session(
     readTimeout = readTimeout,
     connectTimeout = connectTimeout,
     maxRedirects = 0,

contrib/gitlab/src/mill/contrib/gitlab/GitlabUploader.scala

@@ -1,6 +1,7 @@
 package mill.contrib.gitlab
 
 import scala.concurrent.duration._
+import requests.Session
 
 object GitlabUploader {
   type Upload = (String, Array[Byte]) => requests.Response
@@ -11,7 +12,7 @@ class GitlabUploader(
     readTimeout: Int = 5000,
     connectTimeout: Int = 5000
 ) {
-  val http = requests.Session(
+  val http: Session = requests.Session(
     readTimeout = readTimeout,
     connectTimeout = connectTimeout,
     maxRedirects = 0,

contrib/playlib/src/mill/playlib/RouteCompilerWorkerModule.scala

@@ -12,5 +12,5 @@ trait RouteCompilerWorkerModule extends Module {
 private[playlib] object RouteCompilerWorkerModule
     extends ExternalModule
     with RouteCompilerWorkerModule {
-  lazy val millDiscover = Discover[this.type]
+  lazy val millDiscover: Discover[this.type] = Discover[this.type]
 }

contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBWorker.scala

@@ -127,5 +127,5 @@ trait ScalaPBWorkerApi {
 
 object ScalaPBWorkerApi extends ExternalModule {
   def scalaPBWorker: Worker[ScalaPBWorker] = T.worker { new ScalaPBWorker() }
-  lazy val millDiscover = Discover[this.type]
+  lazy val millDiscover: Discover[this.type] = Discover[this.type]
 }

contrib/scoverage/src/mill/contrib/scoverage/ScoverageReportWorker.scala

@@ -40,5 +40,5 @@ object ScoverageReportWorker extends ExternalModule {
 
   def scoverageReportWorker: Worker[ScoverageReportWorker] =
     T.worker { new ScoverageReportWorker() }
-  lazy val millDiscover = Discover[this.type]
+  lazy val millDiscover: Discover[this.type] = Discover[this.type]
 }

contrib/versionfile/src/mill/contrib/versionfile/Version.scala

@@ -1,5 +1,6 @@
 package mill.contrib.versionfile
 
+import scala.util.matching.Regex
 sealed trait Version {
 
   import Version._
@@ -44,7 +45,7 @@ object Bump {
   val minor = "minor"
   val patch = "patch"
 
-  val values = Seq(major, minor, patch)
+  val values: Seq[String] = Seq(major, minor, patch)
 }
 
 object Version {
@@ -60,8 +61,8 @@ object Version {
   case class Release(major: Int, minor: Int, patch: Int) extends Version
   case class Snapshot(major: Int, minor: Int, patch: Int) extends Version
 
-  val ReleaseVersion = raw"""(\d+)\.(\d+)\.(\d+)""".r
-  val MinorSnapshotVersion = raw"""(\d+)\.(\d+)\.(\d+)-SNAPSHOT""".r
+  val ReleaseVersion: Regex = raw"""(\d+)\.(\d+)\.(\d+)""".r
+  val MinorSnapshotVersion: Regex = raw"""(\d+)\.(\d+)\.(\d+)-SNAPSHOT""".r
 
   import upickle.default._
 

contrib/versionfile/src/mill/contrib/versionfile/VersionFileModule.scala

@@ -36,7 +36,7 @@ trait VersionFileModule extends Module {
     writeVersionToFile(versionFile(), version())
   }
 
-  def writeVersionToFile(versionFile: mill.api.PathRef, version: Version) =
+  def writeVersionToFile(versionFile: mill.api.PathRef, version: Version): Unit =
     os.write.over(
       versionFile.path,
       version.toString
@@ -58,7 +58,7 @@ trait VersionFileModule extends Module {
     )
   }
 
-  def generateCommitMessage(version: Version) =
+  def generateCommitMessage(version: Version): String =
     version match {
       case release: Version.Release => s"Setting release version to $version"
       case snapshot: Version.Snapshot => s"Setting next version to $version"

example/src/mill/integration/ExampleTestSuite.scala

@@ -60,7 +60,7 @@ object ExampleTestSuite extends IntegrationTestSuite {
     }
   }
 
-  def processCommandBlock(workspaceRoot: os.Path, commandBlock: String) = {
+  def processCommandBlock(workspaceRoot: os.Path, commandBlock: String): Unit = {
     val commandBlockLines = commandBlock.linesIterator.toVector
 
     val expectedSnippets = commandBlockLines.tail

idea/src/mill/idea/GenIdea.scala

@@ -21,5 +21,5 @@ object GenIdea extends ExternalModule {
     }
   }
 
-  override lazy val millDiscover = Discover[this.type]
+  override lazy val millDiscover: Discover[this.type] = Discover[this.type]
 }

idea/src/mill/idea/GenIdeaImpl.scala

@@ -629,7 +629,7 @@ case class GenIdeaImpl(
     fixedFiles ++ ideaWholeConfigFiles ++ fileComponentContributions ++ libraries ++ moduleFiles
   }
 
-  def relify(p: os.Path) = {
+  def relify(p: os.Path): String = {
     val r = p.relativeTo(ideaDir / "mill_modules")
     (Seq.fill(r.ups)("..") ++ r.segments).mkString("/")
   }
@@ -668,15 +668,15 @@ case class GenIdeaImpl(
     </project>
   }
 
-  def scalaSettingsTemplate() = {
+  def scalaSettingsTemplate(): Elem = {
 //    simpleIdeaConfigFileTemplate(Map("ScalaProjectSettings" -> Map("scFileMode" -> "Ammonite")))
     <project version={"" + ideaConfigVersion}>
       <component name="ScalaProjectSettings">
         <option name="scFileMode" value="Ammonite" />
       </component>
     </project>
   }
-  def miscXmlTemplate(jdkInfo: (String, String)) = {
+  def miscXmlTemplate(jdkInfo: (String, String)): Elem = {
     <project version={"" + ideaConfigVersion}>
       <component name="ProjectRootManager" version="2" languageLevel={jdkInfo._1} project-jdk-name={
       jdkInfo._2
@@ -686,7 +686,7 @@ case class GenIdeaImpl(
     </project>
   }
 
-  def allModulesXmlTemplate(selectors: Seq[String]) = {
+  def allModulesXmlTemplate(selectors: Seq[String]): Elem = {
     <project version={"" + ideaConfigVersion}>
       <component name="ProjectModuleManager">
         <modules>

integration/feature/bsp-install/test/src/BspInstallDebugTests.scala

@@ -5,7 +5,7 @@ import utest._
 
 object BspInstallDebugTests extends IntegrationTestSuite {
 
-  val bsp4jVersion = sys.props.getOrElse("BSP4J_VERSION", ???)
+  val bsp4jVersion: String = sys.props.getOrElse("BSP4J_VERSION", ???)
   // we purposely enable debugging in this simulated test env
   override val debugLog: Boolean = true
 

integration/feature/bsp-install/test/src/BspInstallTests.scala

@@ -4,7 +4,7 @@ import mill.bsp.Constants
 import utest._
 
 object BspInstallTests extends IntegrationTestSuite {
-  val bsp4jVersion = sys.props.getOrElse("BSP4J_VERSION", ???)
+  val bsp4jVersion: String = sys.props.getOrElse("BSP4J_VERSION", ???)
 
   def tests: Tests = Tests {
     test("BSP install") {

integration/feature/bsp-modules/test/src/BspModulesTests.scala

@@ -4,7 +4,7 @@ import mill.bsp.Constants
 import utest._
 
 object BspModulesTests extends IntegrationTestSuite {
-  val bsp4jVersion = sys.props.getOrElse("BSP4J_VERSION", ???)
+  val bsp4jVersion: String = sys.props.getOrElse("BSP4J_VERSION", ???)
 
   def tests: Tests = Tests {
     test("BSP module with foreign modules") {

integration/feature/docannotations/test/src/DocAnnotationsTests.scala

@@ -3,7 +3,7 @@ package mill.integration
 import utest._
 
 object DocAnnotationsTests extends IntegrationTestSuite {
-  def globMatches(glob: String, input: String) = {
+  def globMatches(glob: String, input: String): Boolean = {
     StringContext
       .glob(
         // Normalize the line separator to be `\n` for comparisons

integration/feature/foreign/test/src/ForeignBuildsTest.scala

@@ -3,9 +3,10 @@ package local
 
 import utest._
 import utest.framework.TestPath
+import os.SubPath
 
 object ForeignBuildsTest extends IntegrationTestSuite {
-  override def buildPath = os.sub / "project" / "build.sc"
+  override def buildPath: SubPath = os.sub / "project" / "build.sc"
 
   val tests = Tests {
     initWorkspace()

integration/feature/foreign/test/src/ForeignConflictTest.scala

@@ -2,10 +2,11 @@ package mill.integration
 package local
 
 import utest._
+import os.SubPath
 
 object ForeignConflictTest extends IntegrationTestSuite {
 
-  override def buildPath = os.sub / "conflict" / "build.sc"
+  override def buildPath: SubPath = os.sub / "conflict" / "build.sc"
 
   val tests = Tests {
     initWorkspace()

integration/feature/gen-idea/test/src/GenIdeaExtendedTests.scala

@@ -4,10 +4,11 @@ import mill.integration.IntegrationTestSuite
 import utest._
 
 import scala.util.Try
+import os.Path
 
 object GenIdeaExtendedTests extends IntegrationTestSuite {
 
-  override def scriptSourcePath = super.scriptSourcePath / "extended"
+  override def scriptSourcePath: Path = super.scriptSourcePath / "extended"
 
   private val scalaVersionLibPart = "2_13_6"
 

integration/feature/gen-idea/test/src/GenIdeaTests.scala

@@ -5,10 +5,11 @@ import utest.{Tests, assert, _}
 import scala.util.Try
 import mill.integration.IntegrationTestSuite
 import GenIdeaUtils._
+import os.Path
 
 object GenIdeaTests extends IntegrationTestSuite {
 
-  override def scriptSourcePath = super.scriptSourcePath / "hello-world"
+  override def scriptSourcePath: Path = super.scriptSourcePath / "hello-world"
   private val scalaVersionLibPart = "2_12_5"
 
   def tests: Tests = Tests {