More cleanup for Task.scala (#5168)

- `NamedTask` is now `Task.Named`
- `Target` is now `Task.Simple`
- `TargetImpl` is now `Task.Computed`
- `InputImpl`, `SourcesImpl`, and `SourceImpl` are now `Task.Input`,
`Task.Sources`, and `Task.Source`
- `TaskMacros` has been nested under `Task`
- Unused `TaskBase` was removed

The hierarchy and naming still isn't perfect, but it's better than
before. The top-level `mill.{T, Command, Worker, Source, ...}` aliases
were left in place for convenience, maybe those can be cleaned up too
but that can come later

Author: lihaoyi

build.mill

@@ -12,7 +12,6 @@ import coursier.VersionConstraint
 import mill.main.VcsVersion
 //import com.goyeau.mill.scalafix.ScalafixModule
 import mill._
-import mill.define.NamedTask
 import mill.main.Tasks
 import mill.scalalib._
 import mill.scalalib.api.JvmWorkerUtil

contrib/artifactory/src/mill/contrib/artifactory/ArtifactoryPublishModule.scala

@@ -5,7 +5,6 @@ import mill.api.Result
 import scalalib._
 import mill.contrib.artifactory.ArtifactoryPublishModule.checkArtifactoryCreds
 import mill.define.{ExternalModule, Task}
-import mill.define.Command
 
 trait ArtifactoryPublishModule extends PublishModule {
   def artifactoryUri: String
@@ -28,7 +27,7 @@ trait ArtifactoryPublishModule extends PublishModule {
       artifactorySnapshotUri: String = artifactorySnapshotUri,
       readTimeout: Int = 60000,
       connectTimeout: Int = 5000
-  ): define.Command[Unit] = Task.Command {
+  ): Command[Unit] = Task.Command {
     val PublishModule.PublishData(artifactInfo, artifacts) = publishArtifacts()
     new ArtifactoryPublisher(
       artifactoryUri,

contrib/bintray/src/mill/contrib/bintray/BintrayPublishModule.scala

@@ -5,7 +5,6 @@ import mill.api.Result
 import scalalib._
 import mill.contrib.bintray.BintrayPublishModule.checkBintrayCreds
 import mill.define.{ExternalModule, Task}
-import mill.define.Command
 
 trait BintrayPublishModule extends PublishModule {
 
@@ -37,7 +36,7 @@ trait BintrayPublishModule extends PublishModule {
       release: Boolean = true,
       readTimeout: Int = 60000,
       connectTimeout: Int = 5000
-  ): define.Command[Unit] = Task.Command {
+  ): Command[Unit] = Task.Command {
     new BintrayPublisher(
       bintrayOwner,
       bintrayRepo,

contrib/codeartifact/src/mill/contrib/codeartifact/CodeartifactPublishModule.scala

@@ -16,7 +16,7 @@ trait CodeartifactPublishModule extends PublishModule {
       codeartifactSnapshotUri: String = codeartifactSnapshotUri,
       readTimeout: Int = 60000,
       connectTimeout: Int = 5000
-  ): define.Command[Unit] =
+  ): Command[Unit] =
     Task.Command {
       val PublishModule.PublishData(artifactInfo, artifacts) =
         publishArtifacts()

contrib/flyway/src/mill/contrib/flyway/FlywayModule.scala

@@ -8,9 +8,8 @@ import org.flywaydb.core.internal.configuration.{ConfigUtils => flyway}
 import org.flywaydb.core.internal.info.MigrationInfoDumper
 import scala.jdk.CollectionConverters._
 
-import mill.{T, Task}
+import mill.*
 import mill.define.PathRef
-import mill.define.Command
 import mill.scalalib.{Dep, JavaModule}
 import org.flywaydb.core.api.output.{BaselineResult, CleanResult, MigrateOutput, MigrateResult}
 

contrib/gitlab/src/mill/contrib/gitlab/GitlabPublishModule.scala

@@ -3,7 +3,7 @@ package mill.contrib.gitlab
 import mill._
 import mill.api.Result.{Failure, Success}
 import mill.api.Result
-import mill.define.{Command, ExternalModule, Task}
+import mill.define.{ExternalModule, Task}
 import scalalib._
 
 trait GitlabPublishModule extends PublishModule { outer =>
@@ -30,7 +30,7 @@ trait GitlabPublishModule extends PublishModule { outer =>
   def publishGitlab(
       readTimeout: Int = 60000,
       connectTimeout: Int = 5000
-  ): define.Command[Unit] = Task.Command {
+  ): Command[Unit] = Task.Command {
 
     val gitlabRepo = publishRepository
 

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

@@ -5,7 +5,6 @@ import mill.playlib.api.Versions
 import mill.scalalib._
 import mill.{Args, T}
 import mill.define.PathRef
-import mill.define.Target
 
 trait PlayApiModule extends Dependencies with Router with Server {
   trait PlayTests extends ScalaTests with TestModule.ScalaTest {
@@ -19,7 +18,7 @@ trait PlayApiModule extends Dependencies with Router with Server {
       }
       Seq(mvn"org.scalatestplus.play::scalatestplus-play::${scalatestPlusPlayVersion}")
     }
-    override def sources: Target[Seq[PathRef]] = Task.Sources { moduleDir }
+    override def sources: T[Seq[PathRef]] = Task.Sources { moduleDir }
   }
 
   def start(args: Task[Args] = Task.Anon(Args())) = Task.Command { run(args)() }

contrib/playlib/src/mill/playlib/RouteCompilerWorker.scala

@@ -4,7 +4,7 @@ import mill.define.{TaskCtx, PathRef}
 import mill.api.Result
 import mill.playlib.api.{RouteCompilerType, RouteCompilerWorkerApi}
 import mill.scalalib.api.CompilationResult
-import mill.Task
+import mill.*
 
 private[playlib] class RouteCompilerWorker {
 

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

@@ -1,7 +1,7 @@
 package mill.playlib
 
-import mill.{Module, Task}
-import mill.define.{Discover, ExternalModule, Worker}
+import mill.{Module, Task, Worker}
+import mill.define.{Discover, ExternalModule}
 
 trait RouteCompilerWorkerModule extends Module {
   def routeCompilerWorker: Worker[RouteCompilerWorker] = Task.Worker {

contrib/proguard/test/src/mill/contrib/proguard/ProguardTests.scala

@@ -1,7 +1,7 @@
 package mill.contrib.proguard
 
 import mill.*
-import mill.define.{Discover, Target}
+import mill.define.Discover
 import mill.scalalib.ScalaModule
 import mill.testkit.{TestRootModule, UnitTester}
 import mill.util.Jvm