Scala 3 without Scala 2.13 toolchain (#1383)

## Motivation

Until now Ammonite for Scala 3 was compiled using a mix of the Scala
2.13 and the Scala 3 compiler.
This was great since it allowed us to have Ammonite on Scala 3 before
`fastparse`, `mainargs` and other libraries were even supported on Scala
3, or they were not on par with their Scala 2.13 counterpart.
Now that the ecosystem has caught up with Scala 3, we can avoid using
Scala 2.13 and do everything with Scala 3.
This has the benefit that now all the classpath contains only Scala 3
libraries and we can finally invoke Scala 3 macros in the included
libraries like `upickle`.
Also, the build gets much simpler since we don't have to do tricks to
swap dependencies at runtime and manually remove transitive
dependencies.
The only dependency that still is on Scala 2.13 is scalameta `common`,
for which we still force the Scala 3 version of its `sourcecode`
dependency to avoid double dependencies at runtime.

## uPickle macros on Scala 3

<img width="867" alt="upickle"
src="https://github.com/com-lihaoyi/Ammonite/assets/5793054/05817a4a-58f7-4e33-9fb5-f829590911df">

## Breaking changes

- Drop support for Scala 3.1
- Drop support for Scala 2.13.0
- Scala 3 artifacts don't have the `-cross` naming convention anymore
but are just like Scala 2 artifacts except for the `_3` or `_3.x.y`
suffix
- `ammonite.util.Bind` now depends on
[typename](https://github.com/tpolecat/typename) instead of
scala-reflect (which doesn't have a Scala 3 counterpart
- `scala-java8-compat` updated to `1.0.2`
- `mainargs` updated to `0.5.4`
- `requests` updated to `0.8.0`
- `interp.api.APIHolder.value` is now `final`
- `typeOf` removed from Scala 3 API (was not supported already)
- Vararg command line arguments now use `mainargs.Leftover`

.github/workflows/actions.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         java-version: [8, 11]
-        scala-version: [2.12.18, 2.13.12, 3.3.1]
+        scala-binary-version: [2.12, 2.13, 3]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -23,13 +23,13 @@ jobs:
       - uses: actions/setup-java@v1
         with:
           java-version: ${{ matrix.java-version }}
-      - run: ./mill -i unitTest "${{ matrix.scala-version }}"
+      - run: ./mill -i unitTest "${{ matrix.scala-binary-version }}"
   itest:
     strategy:
       fail-fast: false
       matrix:
         java-version: [8, 11]
-        scala-version: [2.12.18, 2.13.12, 3.3.1]
+        scala-version: [2.12.18, 2.13.12, 3.2.2, 3.3.1]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -39,3 +39,17 @@ jobs:
         with:
           java-version: ${{ matrix.java-version }}
       - run: ./mill -i integrationTest ${{ matrix.scala-version }}
+  publishLocal:
+    strategy:
+      fail-fast: false
+      matrix:
+        scala-version: [2.12.18, 2.13.12, 3.2.2]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 8
+      - run: ./mill -i __[${{ matrix.scala-version }}].__.publishLocal

.gitignore

@@ -13,3 +13,4 @@ out
 .bloop
 .vscode
 .metals
+.bsp

.mill-version

@@ -1 +1 @@
-0.10.11
+0.10.13

amm/interp/api/src/main/scala/ammonite/interp/api/APIHolder.scala

@@ -2,5 +2,5 @@ package ammonite.interp.api
 
 class APIHolder[T >: Null <: AnyRef] {
   var value0: T = null
-  implicit lazy val value = value0
+  implicit final lazy val value: T = value0
 }

amm/interp/src/main/scala/ammonite/interp/Interpreter.scala

@@ -157,7 +157,7 @@ class Interpreter(val compilerBuilder: CompilerBuilder,
   def watch(p: os.Path) = watchedValues.append(
     (Watchable.Path(p), Watchable.pathSignature(p))
   )
-  def watchValue[T](v: => T) = watchedValues.append((() => v.hashCode, v.hashCode()))
+  def watchValue[T](v: => T) = watchedValues.append((new Watchable { def poll() = v.hashCode.toLong }, v.hashCode().toLong))
 
   def resolveSingleImportHook(
     source: CodeSource,
@@ -214,11 +214,6 @@ class Interpreter(val compilerBuilder: CompilerBuilder,
                          source: CodeSource,
                          wrapperPath: Seq[Name]): Res[ImportHookInfo] = synchronized{
 
-    // Fake an update to the classpath to force re-creation of the compiler
-    // Workaround for https://github.com/scala/bug/issues/11564#issuecomment-501834821,
-    // which I caused in 2.13.0 and should be fixed in 2.13.1
-    if (scala.util.Properties.versionNumberString == "2.13.0") headFrame.addClasspath(Nil)
-
     for (hookImports <- Res.map(importTrees)(resolveSingleImportHook(source, _, wrapperPath)))
     yield ImportHookInfo(
       Imports(hookImports.flatten.flatMap(_.value)),

amm/interp/src/main/scala/ammonite/interp/script/SemanticdbProcessor.scala

@@ -27,7 +27,7 @@ object SemanticdbProcessor {
 
     val mapRange = {
       val adjust0 = adjust(module.blocks.length)
-      range: scala.meta.internal.semanticdb.Range =>
+      (range: scala.meta.internal.semanticdb.Range) =>
         for {
           (startLine, startChar) <- adjust0(range.startLine, range.startCharacter)
           (endLine, endChar) <- adjust0(range.endLine, range.endCharacter)

amm/repl/api/src/main/scala-2/ammonite/repl/FullReplAPIScalaVersionSpecific.scala

@@ -0,0 +1,10 @@
+package ammonite.repl
+
+import scala.reflect.runtime.universe._
+
+trait FullReplAPIScalaVersionSpecific {
+
+  def typeOf[T: WeakTypeTag] = scala.reflect.runtime.universe.weakTypeOf[T]
+  def typeOf[T: WeakTypeTag](t: => T) = scala.reflect.runtime.universe.weakTypeOf[T]
+
+}

amm/repl/api/src/main/scala-2/ammonite/repl/api/ReplAPIScalaVersionSpecific.scala

@@ -0,0 +1,20 @@
+package ammonite.repl.api
+
+import scala.reflect.runtime.universe._
+
+trait ReplAPIScalaVersionSpecific {
+
+  /**
+   * Get the `Type` object of [[T]]. Useful for finding
+   * what its methods are and what you can do with it
+   */
+  def typeOf[T: WeakTypeTag]: Type
+
+  /**
+   * Get the `Type` object representing the type of `t`. Useful
+   * for finding what its methods are and what you can do with it
+   *
+   */
+  def typeOf[T: WeakTypeTag](t: => T): Type
+
+}

amm/repl/api/src/main/scala-3/ammonite/repl/FullReplAPIScalaVersionSpecific.scala

@@ -0,0 +1,3 @@
+package ammonite.repl
+
+trait FullReplAPIScalaVersionSpecific

amm/repl/api/src/main/scala-3/ammonite/repl/api/ReplAPIScalaVersionSpecific.scala

@@ -0,0 +1,3 @@
+package ammonite.repl.api
+
+trait ReplAPIScalaVersionSpecific

amm/repl/api/src/main/scala/ammonite/repl/FullReplAPI.scala

@@ -5,16 +5,11 @@ import ammonite.repl.api.ReplAPI
 import ammonite.util.{Bind, _}
 import ammonite.util.Util.newLine
 
-import scala.reflect.runtime.universe._
-
 import scala.collection.mutable
 import scala.reflect.ClassTag
 import scala.reflect.classTag
 
-trait FullReplAPI extends ReplAPI{ replApi =>
-
-  def typeOf[T: WeakTypeTag] = scala.reflect.runtime.universe.weakTypeOf[T]
-  def typeOf[T: WeakTypeTag](t: => T) = scala.reflect.runtime.universe.weakTypeOf[T]
+trait FullReplAPI extends ReplAPI with FullReplAPIScalaVersionSpecific { replApi =>
 
   protected val colors: Ref[Colors]
 

amm/repl/api/src/main/scala/ammonite/repl/api/ReplAPI.scala

@@ -2,12 +2,7 @@ package ammonite.repl.api
 
 import ammonite.util._
 
-import scala.reflect.runtime.universe._
-
-
-
-
-trait ReplAPI {
+trait ReplAPI extends ReplAPIScalaVersionSpecific {
 
   /**
    * Read/writable prompt for the shell. Use this to change the
@@ -47,19 +42,6 @@ trait ReplAPI {
    */
   def history: History
 
-  /**
-   * Get the `Type` object of [[T]]. Useful for finding
-   * what its methods are and what you can do with it
-   */
-  def typeOf[T: WeakTypeTag]: Type
-
-  /**
-   * Get the `Type` object representing the type of `t`. Useful
-   * for finding what its methods are and what you can do with it
-   *
-   */
-  def typeOf[T: WeakTypeTag](t: => T): Type
-
   /**
    * Throw away the current scala.tools.nsc.Global and get a new one
    */

amm/repl/api/src/main/scala/ammonite/repl/tools/Util.scala

@@ -5,7 +5,9 @@ object Util {
   /**
     * Additional [[mainargs.TokensReader]] instance to teach it how to read Ammonite paths
     */
-  implicit object PathRead
-  extends mainargs.TokensReader[os.Path]("path", strs => Right(os.Path(strs.last, os.pwd)))
+  implicit object PathRead extends mainargs.TokensReader.Simple[os.Path] {
+    def shortName = "path"
+    def read(strs: Seq[String]) = Right(os.Path(strs.last, os.pwd))
+  }
 
 }

amm/repl/api/src/main/scala/ammonite/runtime/tools/Tools.scala

@@ -43,7 +43,7 @@ case class GrepResult(spans: Seq[(Int, Int)], text: fansi.Str)
 object GrepResult{
   case class Color(highlight: fansi.Attrs, dotDotDotColor: fansi.Attrs)
   object Color{
-    implicit val defaultColor = Color(
+    implicit val defaultColor: Color = Color(
       fansi.Back.Yellow ++ fansi.Color.Blue,
       fansi.Attrs.Empty
     )
@@ -211,8 +211,8 @@ object time {
 object browse{
   case class Strings(values: Seq[String])
   object Strings{
-    implicit def stringPrefix(s: String) = Strings(Seq(s))
-    implicit def stringSeqPrefix(s: Seq[String]) = Strings(s)
+    implicit def stringPrefix(s: String): Strings = Strings(Seq(s))
+    implicit def stringSeqPrefix(s: Seq[String]): Strings = Strings(s)
   }
   // R -> show ansi-colors as colors, M -> show current-browse-% bar
   val lessViewer = Seq("less", "-RM")

amm/repl/src/main/scala-2/ammonite/main/DefaultsScalaVersionSpecific.scala

@@ -0,0 +1,14 @@
+package ammonite.main
+
+import ammonite.util.{ImportData, Imports}
+
+private[main] trait DefaultsScalaVersionSpecific {
+  val replImports = Imports(
+    ImportData("""ammonite.repl.ReplBridge.value.{
+      codeColorsImplicit,
+      tprintColorsImplicit,
+      show,
+      typeOf
+    }""")
+  )
+}

amm/repl/src/main/scala-3/ammonite/main/DefaultsScalaVersionSpecific.scala

@@ -0,0 +1,13 @@
+package ammonite.main
+
+import ammonite.util.{ImportData, Imports}
+
+private[main] trait DefaultsScalaVersionSpecific {
+  val replImports = Imports(
+    ImportData("""ammonite.repl.ReplBridge.value.{
+      codeColorsImplicit,
+      tprintColorsImplicit,
+      show
+    }""")
+  )
+}