Scala 3 Migration

.github/workflows/pr-build.yaml

@@ -22,7 +22,11 @@ jobs:
           distribution: 'adopt'
       - name: Run mill tests
         run: ./mill __.test
-      - name: Compile with sbt
+      - name: Compile Scala 2.13 with sbt
+        run: sbt ++2.13 compile bench/compile bench/jmh:compile
+      - name: Compile Scala 2.13 with sbt
         run: sbt compile bench/compile bench/jmh:compile
-      - name: Run sbt tests
+      - name: Run sbt tests (Scala 2.13)
+        run: sbt ++2.13 test
+      - name: Run sbt tests (Scala 3)
         run: sbt test

bench/src/main/scala/sjsonnet/MaterializerBenchmark.scala

@@ -6,6 +6,7 @@ import java.util.concurrent.TimeUnit
 import org.openjdk.jmh.annotations._
 import org.openjdk.jmh.infra._
 import ujson.JsVisitor
+import scala.compiletime.uninitialized
 
 @BenchmarkMode(Array(Mode.AverageTime))
 @Fork(2)
@@ -16,8 +17,8 @@ import ujson.JsVisitor
 @State(Scope.Benchmark)
 class MaterializerBenchmark {
 
-  private var interp: Interpreter = _
-  private var value: Val = _
+  private var interp: Interpreter = uninitialized
+  private var value: Val = uninitialized
 
   @Setup
   def setup(): Unit = {

bench/src/main/scala/sjsonnet/OptimizerBenchmark.scala

@@ -10,6 +10,7 @@ import org.openjdk.jmh.annotations._
 import org.openjdk.jmh.infra._
 
 import scala.collection.mutable
+import scala.compiletime.uninitialized
 
 @BenchmarkMode(Array(Mode.AverageTime))
 @Fork(2)
@@ -20,16 +21,17 @@ import scala.collection.mutable
 @State(Scope.Benchmark)
 class OptimizerBenchmark {
 
-  private var inputs: Iterable[(Expr, FileScope)] = _
-  private var allFiles: IndexedSeq[(Path, String)] = _
-  private var ev: EvalScope = _
+  private var inputs: Iterable[(Expr, FileScope)] = uninitialized
+  private var allFiles: IndexedSeq[(Path, String)] = uninitialized
+  private var ev: EvalScope = uninitialized
 
   @Setup
   def setup(): Unit = {
     val (allFiles, ev) = MainBenchmark.findFiles()
     this.inputs = allFiles.map { case (p, s) =>
-      fastparse.parse(s, new Parser(p, true, mutable.HashMap.empty, mutable.HashMap.empty).document(_)) match {
+      fastparse.parse(s, new Parser(p, true, mutable.HashMap.empty, mutable.HashMap.empty).document(using _)) match {
         case Success(v, _) => v
+        case _ => throw new RuntimeException("Parse Failed")
       }
     }
     this.ev = ev

bench/src/main/scala/sjsonnet/ParserBenchmark.scala

@@ -7,6 +7,7 @@ import scala.collection.mutable.HashMap
 import fastparse.Parsed.Success
 import org.openjdk.jmh.annotations._
 import org.openjdk.jmh.infra._
+import scala.compiletime.uninitialized
 
 @BenchmarkMode(Array(Mode.AverageTime))
 @Fork(2)
@@ -17,8 +18,8 @@ import org.openjdk.jmh.infra._
 @State(Scope.Benchmark)
 class ParserBenchmark {
 
-  private var allFiles: IndexedSeq[(Path, String)] = _
-  private var interp: Interpreter = _
+  private var allFiles: IndexedSeq[(Path, String)] = uninitialized
+  private var interp: Interpreter = uninitialized
 
   @Setup
   def setup(): Unit =
@@ -27,8 +28,8 @@ class ParserBenchmark {
   @Benchmark
   def main(bh: Blackhole): Unit = {
     bh.consume(allFiles.foreach { case (p, s) =>
-      val res = fastparse.parse(s, new Parser(p, true, HashMap.empty, HashMap.empty).document(_))
-      bh.consume(res.asInstanceOf[Success[_]])
+      val res = fastparse.parse(s, new Parser(p, true, HashMap.empty, HashMap.empty).document(using _))
+      bh.consume(res.asInstanceOf[Success[?]])
     })
   }
 }

build.sbt

@@ -1,29 +1,55 @@
 val sjsonnetVersion = "0.4.4"
 
-scalaVersion in Global := "2.13.4"
+val scala213 = "2.13.15"
+val scala3 = "3.5.1"
+
+val commonOptions: Seq[String] = Seq(
+  "-opt:l:inline",
+  "-opt-inline-from:sjsonnet.*,sjsonnet.**",
+)
 
 cancelable in Global := true
+publish / skip := true
 
 lazy val main = (project in file("sjsonnet"))
   .settings(
-    Compile / scalacOptions ++= Seq("-opt:l:inline", "-opt-inline-from:sjsonnet.*,sjsonnet.**"),
+    name := "sjsonnet",
+
+    // Enable cross-compilation
+    scalaVersion := scala3,
+    crossScalaVersions := Seq(scala213, scala3),
+    scalacOptions ++= {
+      (CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((3, _)) =>
+          commonOptions ++ Seq(
+            // options dedicated for cross build / migration to Scala 3
+            "-source:3.5-migration"
+          )
+        case _ =>
+          commonOptions ++ Seq(
+            "-Xsource:3"
+          )
+      })
+    },
+
+
     Test / fork := true,
     Test / baseDirectory := (ThisBuild / baseDirectory).value,
     libraryDependencies ++= Seq(
-      "com.lihaoyi" %% "fastparse" % "2.3.1",
-      "com.lihaoyi" %% "pprint" % "0.6.1",
-      "com.lihaoyi" %% "ujson" % "1.3.7",
-      "com.lihaoyi" %% "scalatags" % "0.9.3",
-      "com.lihaoyi" %% "os-lib" % "0.7.2",
-      "com.lihaoyi" %% "mainargs" % "0.2.0",
+      "com.lihaoyi" %% "fastparse" % "3.1.1",
+      "com.lihaoyi" %% "pprint" % "0.9.0",
+      "com.lihaoyi" %% "ujson" % "4.0.0",
+      "com.lihaoyi" %% "scalatags" % "0.12.0",
+      "com.lihaoyi" %% "os-lib" % "0.10.3",
+      "com.lihaoyi" %% "mainargs" % "0.7.5",
       "org.lz4" % "lz4-java" % "1.8.0",
-      "org.json" % "json" % "20211205",
-      "org.scala-lang.modules" %% "scala-collection-compat" % "2.4.0",
-      "org.tukaani" % "xz" % "1.8",
-      "org.yaml" % "snakeyaml" % "1.30",
+      "org.json" % "json" % "20240303",
+      "org.scala-lang.modules" %% "scala-collection-compat" % "2.12.0",
+      "org.tukaani" % "xz" % "1.9",
+      "org.yaml" % "snakeyaml" % "2.0",
     ),
     libraryDependencies ++= Seq(
-      "com.lihaoyi" %% "utest" % "0.7.7",
+      "com.lihaoyi" %% "utest" % "0.8.3",
     ).map(_ % "test"),
     testFrameworks += new TestFramework("utest.runner.Framework"),
     (Compile / unmanagedSourceDirectories) := Seq(
@@ -56,4 +82,12 @@ lazy val bench = (project in file("bench"))
   .enablePlugins(JmhPlugin)
   .settings(
     run / fork := true,
+    // Do not cross-compile the benchmark
+    scalaVersion := scala3,
   )
+
+lazy val root = (project in file("."))
+  .aggregate(main)
+  .settings(
+    publishArtifact := false
+  )

project/plugins.sbt

@@ -1,2 +1 @@
-//addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.3.7")
-addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.3.3")
+addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.3.3")

sjsonnet/src-jvm-native/sjsonnet/CachedResolvedFile.scala

@@ -26,7 +26,7 @@ class CachedResolvedFile(val resolvedImportPath: OsPath, memoryLimitBytes: Long,
   // Assert that the file is less than limit
   assert(jFile.length() <= memoryLimitBytes, s"Resolved import path ${resolvedImportPath} is too large: ${jFile.length()} bytes > ${memoryLimitBytes} bytes")
 
-  private[this] val resolvedImportContent: StaticResolvedFile = {
+  private val resolvedImportContent: StaticResolvedFile = {
     if (jFile.length() > cacheThresholdBytes) {
       // If the file is too large, then we will just read it from disk
       null
@@ -35,7 +35,7 @@ class CachedResolvedFile(val resolvedImportPath: OsPath, memoryLimitBytes: Long,
     }
   }
 
-  private[this] def readString(jFile: File): String = {
+  private def readString(jFile: File): String = {
     new String(Files.readAllBytes(jFile.toPath), StandardCharsets.UTF_8);
   }
 

sjsonnet/src-jvm-native/sjsonnet/OsPath.scala

@@ -29,6 +29,6 @@ case class OsPath(p: os.Path) extends Path{
         ":" + Util.prettyIndex(lineStarts, offset)
       }
 
-    p.relativeTo(os.pwd) + offsetStr
+    p.relativeTo(os.pwd).toString() + offsetStr
   }
 }

sjsonnet/src-jvm-native/sjsonnet/SjsonnetMain.scala

@@ -64,7 +64,7 @@ object SjsonnetMain {
     val doc = "usage: sjsonnet  [sjsonnet-options] script-file"
     val result = for{
       config <- parser.constructEither(
-        args,
+        args.toIndexedSeq,
         customName = name, customDoc = doc,
         autoPrintHelpAndExit = None
       )
@@ -113,7 +113,7 @@ object SjsonnetMain {
   def writeFile(config: Config, f: os.Path, contents: String): Either[String, Unit] =
     handleWriteFile(os.write.over(f, contents, createFolders = config.createDirs.value))
 
-  def writeToFile(config: Config, wd: os.Path)(materialize: Writer => Either[String, _]): Either[String, String] = {
+  def writeToFile(config: Config, wd: os.Path)(materialize: Writer => Either[String, ?]): Either[String, String] = {
     config.outputFile match{
       case None =>
         val sw = new StringWriter
@@ -205,12 +205,12 @@ object SjsonnetMain {
       importer = importer match{
         case Some(i) => new Importer {
           def resolve(docBase: Path, importName: String): Option[Path] =
-            i(docBase, importName).map(OsPath)
+            i(docBase, importName).map(OsPath.apply)
           def read(path: Path): Option[ResolvedFile] = {
             readPath(path)
           }
         }
-        case None => resolveImport(config.jpaths.map(os.Path(_, wd)).map(OsPath(_)), allowedInputs)
+        case None => resolveImport(config.jpaths.map(os.Path(_, wd)).map(OsPath.apply), allowedInputs)
       },
       parseCache,
       settings = new Settings(
@@ -246,8 +246,8 @@ object SjsonnetMain {
                       Right(writer.toString)
                     }
                   }
-                  relPath = os.FilePath(multiPath) / os.RelPath(f)
-                  _ <- writeFile(config, relPath.resolveFrom(wd), rendered)
+                  relPath = os.Path(multiPath, wd) / f
+                  _ <- writeFile(config, relPath, rendered)
                 } yield relPath
               }
 
@@ -299,7 +299,7 @@ object SjsonnetMain {
    * of caching on top of the underlying file system. Small files are read into memory, while large
    * files are read from disk.
    */
-  private[this] def readPath(path: Path): Option[ResolvedFile] = {
+  private def readPath(path: Path): Option[ResolvedFile] = {
     val osPath = path.asInstanceOf[OsPath].p
     if (os.exists(osPath) && os.isFile(osPath)) {
       Some(new CachedResolvedFile(path.asInstanceOf[OsPath], memoryLimitBytes = Int.MaxValue.toLong))

sjsonnet/src-jvm/sjsonnet/Platform.scala

@@ -2,13 +2,13 @@ package sjsonnet
 
 import org.json.JSONObject
 
-import java.io.{ByteArrayOutputStream, BufferedInputStream, File, FileInputStream}
+import java.io.{BufferedInputStream, ByteArrayOutputStream, File, FileInputStream}
 import java.util.Base64
 import java.util.zip.GZIPOutputStream
-import net.jpountz.xxhash.{StreamingXXHash64, XXHashFactory, XXHash64}
+import net.jpountz.xxhash.{StreamingXXHash64, XXHash64, XXHashFactory}
 import org.tukaani.xz.LZMA2Options
 import org.tukaani.xz.XZOutputStream
-import org.yaml.snakeyaml.Yaml
+import org.yaml.snakeyaml.{LoaderOptions, Yaml}
 import org.yaml.snakeyaml.constructor.Constructor
 
 object Platform {
@@ -23,12 +23,13 @@ object Platform {
       outputStream.close()
     }
   }
+
   def gzipString(s: String): String = {
     gzipBytes(s.getBytes())
   }
 
   /**
-   *  Valid compression levels are 0 (no compression) to 9 (maximum compression).
+   * Valid compression levels are 0 (no compression) to 9 (maximum compression).
    */
   def xzBytes(b: Array[Byte], compressionLevel: Option[Int]): String = {
     val outputStream: ByteArrayOutputStream = new ByteArrayOutputStream(b.length)
@@ -49,14 +50,15 @@ object Platform {
   }
 
   def yamlToJson(yamlString: String): String = {
-    val yaml: java.util.LinkedHashMap[String, Object] = new Yaml(new Constructor(classOf[java.util.LinkedHashMap[String, Object]])).load(yamlString)
+    val options = new LoaderOptions()
+    val yaml: java.util.LinkedHashMap[String, Object] = new Yaml(new Constructor(classOf[java.util.LinkedHashMap[String, Object]], options)).load(yamlString)
     new JSONObject(yaml).toString()
   }
 
   private def computeHash(algorithm: String, s: String) = {
     java.security.MessageDigest.getInstance(algorithm)
       .digest(s.getBytes("UTF-8"))
-      .map{ b => String.format("%02x", (b & 0xff).asInstanceOf[Integer])}
+      .map { b => String.format("%02x", Integer.valueOf(b & 0xff)) }
       .mkString
   }
 
@@ -71,7 +73,7 @@ object Platform {
   // Same as go-jsonnet https://github.com/google/go-jsonnet/blob/2b4d7535f540f128e38830492e509a550eb86d57/builtins.go#L959
   def sha3(s: String): String = computeHash("SHA3-512", s)
 
-  private[this] val xxHashFactory = XXHashFactory.fastestInstance()
+  private val xxHashFactory = XXHashFactory.fastestInstance()
 
   def hashFile(file: File): String = {
     val buffer = new Array[Byte](8192)