NIT Refactor

  - remove redundant braces
  - apply Scala 3 syntax where applicable
  - remove redundant conversions
  - simplify transformations
  - fill-in missing type declarations
  - explicit annotate @tailrec functions
  - remove redundant regex escapes

Author: Gedochao

modules/build/src/main/scala/scala/build/Build.scala

@@ -9,14 +9,15 @@ import java.io.File
 import java.nio.file.{FileSystemException, Path}
 import java.util.concurrent.{ScheduledExecutorService, ScheduledFuture}
 
+import scala.annotation.tailrec
 import scala.build.EitherCps.{either, value}
-import scala.build.Ops._
+import scala.build.Ops.*
 import scala.build.compiler.{ScalaCompiler, ScalaCompilerMaker}
-import scala.build.errors._
+import scala.build.errors.*
 import scala.build.internal.{Constants, CustomCodeWrapper, MainClass, Util}
-import scala.build.options._
+import scala.build.options.*
 import scala.build.options.validation.ValidationException
-import scala.build.postprocessing._
+import scala.build.postprocessing.*
 import scala.collection.mutable.ListBuffer
 import scala.concurrent.duration.DurationInt
 import scala.util.Properties
@@ -329,7 +330,7 @@ object Build {
     builds
   }
 
-  private def copyResourceToClassesDir(build: Build) = build match {
+  private def copyResourceToClassesDir(build: Build): Unit = build match {
     case b: Build.Successful =>
       for {
         resourceDirPath  <- b.sources.resourceDirs.filter(os.exists(_))
@@ -502,7 +503,7 @@ object Build {
     logger: Logger,
     options: BuildOptions
   ): Either[BuildException, Unit] = {
-    val (errors, otherDiagnostics) = options.validate.toSeq.partition(_.severity == Severity.Error)
+    val (errors, otherDiagnostics) = options.validate.partition(_.severity == Severity.Error)
     logger.log(otherDiagnostics)
     if (errors.nonEmpty)
       Left(CompositeBuildException(errors.map(new ValidationException(_))))
@@ -541,7 +542,7 @@ object Build {
       logger
     ))
 
-    def run() = {
+    def run(): Unit = {
       try {
         val res = build(
           inputs,
@@ -940,6 +941,7 @@ object Build {
       def onError(t: Throwable): Unit = {
         // TODO Log that properly
         System.err.println("got error:")
+        @tailrec
         def printEx(t: Throwable): Unit =
           if (t != null) {
             System.err.println(t)
@@ -973,7 +975,7 @@ object Build {
     }
 
     private val lock                  = new Object
-    private var f: ScheduledFuture[_] = null
+    private var f: ScheduledFuture[?] = _
     private val waitFor               = 50.millis
     private val runnable: Runnable = { () =>
       lock.synchronized {
@@ -1080,7 +1082,7 @@ object Build {
         command.iterator.map(_ + System.lineSeparator()).mkString
     )
 
-    new ProcessBuilder(command: _*)
+    new ProcessBuilder(command*)
       .inheritIO()
       .start()
       .waitFor()

modules/build/src/main/scala/scala/build/CrossSources.scala

@@ -1,10 +1,10 @@
 package scala.build
 
 import scala.build.EitherCps.{either, value}
-import scala.build.Ops._
+import scala.build.Ops.*
 import scala.build.errors.{BuildException, CompositeBuildException}
 import scala.build.options.{BuildOptions, BuildRequirements, HasBuildRequirements, Scope}
-import scala.build.preprocessing._
+import scala.build.preprocessing.*
 
 final case class CrossSources(
   paths: Seq[HasBuildRequirements[(os.Path, os.RelPath)]],

modules/build/src/main/scala/scala/build/Inputs.scala

@@ -57,7 +57,7 @@ final case class Inputs(
 
   private lazy val inputsHash: String =
     Inputs.inputsHash(elements)
-  lazy val projectName = {
+  lazy val projectName: String = {
     val needsSuffix = mayAppendHash && (elements match {
       case Seq(d: Inputs.Directory) => d.path != workspace
       case _                        => true
@@ -87,19 +87,18 @@ final case class Inputs(
     if (forbidden.exists(workspace.startsWith)) inHomeDir(directories)
     else this
   def checkAttributes(directories: Directories): Inputs = {
+    @tailrec
     def existingParent(p: os.Path): Option[os.Path] =
       if (os.exists(p)) Some(p)
       else if (p.segmentCount <= 0) None
       else existingParent(p / os.up)
     def reallyOwnedByUser(p: os.Path): Boolean =
       if (Properties.isWin)
-        p.toIO.canWrite() // Wondering if there's a better way to do that…
+        p.toIO.canWrite // Wondering if there's a better way to do that…
       else
         os.owner(p) == os.owner(os.home) &&
-        p.toIO.canWrite()
-    val canWrite = existingParent(workspace)
-      .map(reallyOwnedByUser)
-      .getOrElse(false)
+        p.toIO.canWrite
+    val canWrite = existingParent(workspace).exists(reallyOwnedByUser)
     if (canWrite) this
     else inHomeDir(directories)
   }
@@ -123,7 +122,7 @@ final case class Inputs(
         Iterator(v.content, bytes("\n"))
     }
     val md = MessageDigest.getInstance("SHA-1")
-    it.foreach(md.update(_))
+    it.foreach(md.update)
     val digest        = md.digest()
     val calculatedSum = new BigInteger(1, digest)
     String.format(s"%040x", calculatedSum)
@@ -188,15 +187,15 @@ object Inputs {
 
   final case class Script(base: os.Path, subPath: os.SubPath)
       extends OnDisk with SourceFile with AnyScalaFile with AnyScript {
-    lazy val path = base / subPath
+    lazy val path: os.Path = base / subPath
   }
   final case class ScalaFile(base: os.Path, subPath: os.SubPath)
       extends OnDisk with SourceFile with AnyScalaFile {
-    lazy val path = base / subPath
+    lazy val path: os.Path = base / subPath
   }
   final case class JavaFile(base: os.Path, subPath: os.SubPath)
       extends OnDisk with SourceFile with Compiled {
-    lazy val path = base / subPath
+    lazy val path: os.Path = base / subPath
   }
   final case class Directory(path: os.Path)         extends OnDisk with Compiled
   final case class ResourceDirectory(path: os.Path) extends OnDisk
@@ -226,13 +225,13 @@ object Inputs {
         Iterator(bytes("virtual:"), v.content, bytes("\n"))
     }
     val md = MessageDigest.getInstance("SHA-1")
-    it.foreach(md.update(_))
+    it.foreach(md.update)
     val digest        = md.digest()
     val calculatedSum = new BigInteger(1, digest)
     String.format(s"%040x", calculatedSum).take(10)
   }
 
-  def homeWorkspace(elements: Seq[Element], directories: Directories) = {
+  def homeWorkspace(elements: Seq[Element], directories: Directories): os.Path = {
     val hash0 = inputsHash(elements)
     val dir   = directories.virtualProjectsDir / hash0.take(2) / s"project-${hash0.drop(2)}"
     os.makeDir.all(dir)
@@ -292,7 +291,7 @@ object Inputs {
   }
 
   private val githubGistsArchiveRegex: Regex =
-    s""":\\/\\/gist\\.github\\.com\\/[^\\/]*?\\/[^\\/]*$$""".r
+    s"""://gist\\.github\\.com/[^/]*?/[^/]*$$""".r
 
   private def resolve(path: String, content: Array[Byte]): Element =
     if (path.endsWith(".scala")) VirtualScalaFile(content, path)
@@ -307,7 +306,7 @@ object Inputs {
     val zipInputStream = new ZipInputStream(new ByteArrayInputStream(content))
     @tailrec
     def readArchive(acc: Seq[Element]): Seq[Element] =
-      Option(zipInputStream.getNextEntry()) match {
+      Option(zipInputStream.getNextEntry) match {
         case Some(entry) if entry.isDirectory => readArchive(acc)
         case Some(entry) =>
           val content = zipInputStream.readAllBytes()

modules/build/src/main/scala/scala/build/Sources.scala

@@ -2,7 +2,7 @@ package scala.build
 
 import scala.build.internal.CodeWrapper
 import scala.build.options.{BuildOptions, Scope}
-import scala.build.preprocessing._
+import scala.build.preprocessing.*
 
 final case class Sources(
   paths: Seq[(os.Path, os.RelPath)],

modules/build/src/main/scala/scala/build/internal/NativeBuilderHelper.scala

@@ -49,7 +49,7 @@ object NativeBuilderHelper {
     dest: os.Path,
     nativeWorkDir: os.Path,
     currentProjectSha: String
-  ) = {
+  ): Unit = {
     val projectShaPath = resolveProjectShaPath(nativeWorkDir)
     os.write.over(projectShaPath, currentProjectSha, createFolders = true)
 

modules/build/src/main/scala/scala/build/preprocessing/ScalaPreprocessor.scala

@@ -7,11 +7,11 @@ import dependency.parser.DependencyParser
 import java.nio.charset.StandardCharsets
 
 import scala.build.EitherCps.{either, value}
-import scala.build.Ops._
-import scala.build.errors._
+import scala.build.Ops.*
+import scala.build.errors.*
 import scala.build.internal.Util
 import scala.build.options.{BuildOptions, BuildRequirements, ClassPathOptions, ShadowingSeq}
-import scala.build.preprocessing.directives._
+import scala.build.preprocessing.directives.*
 import scala.build.{Inputs, Logger, Position, Positioned}
 
 case object ScalaPreprocessor extends Preprocessor {
@@ -177,9 +177,9 @@ case object ScalaPreprocessor extends Preprocessor {
     path: Either[String, os.Path]
   ): Either[BuildException, Option[SpecialImportsProcessingOutput]] = either {
 
-    import fastparse._
+    import fastparse.*
 
-    import scala.build.internal.ScalaParse._
+    import scala.build.internal.ScalaParse.*
 
     val res = parse(content, Header(_))
 
@@ -315,7 +315,7 @@ case object ScalaPreprocessor extends Preprocessor {
             updatedRequirements.scoped,
             updatedContentOpt
           ))
-        case Seq(h, t @ _*) =>
+        case Seq(h, t*) =>
           val errors = ::(
             handleUnusedValues(ScopedDirective(h, path, cwd)),
             t.map(d => handleUnusedValues(ScopedDirective(d, path, cwd))).toList

modules/cli/src/main/scala/scala/cli/commands/Package.scala

@@ -195,7 +195,7 @@ object Package extends ScalaCommand[PackageOptions] {
     def alreadyExistsCheck(): Unit = {
       val alreadyExists = !force &&
         os.exists(destPath) &&
-        expectedModifyEpochSecondOpt.forall(exp => os.mtime(destPath) != exp)
+        !expectedModifyEpochSecondOpt.contains(os.mtime(destPath))
       if (alreadyExists) {
         val msg =
           if (expectedModifyEpochSecondOpt.isEmpty) s"$printableDest already exists"
@@ -685,7 +685,7 @@ object Package extends ScalaCommand[PackageOptions] {
     noOpt: Boolean,
     logger: Logger
   ): Either[BuildException, os.Path] =
-    Library.withLibraryJar(build, dest.last.toString.stripSuffix(".jar")) { mainJar =>
+    Library.withLibraryJar(build, dest.last.stripSuffix(".jar")) { mainJar =>
       val classPath  = os.Path(mainJar, os.pwd) +: build.artifacts.classPath
       val linkingDir = os.temp.dir(prefix = "scala-cli-js-linking")
       either {
@@ -771,7 +771,7 @@ object Package extends ScalaCommand[PackageOptions] {
     if (cacheData.changed)
       Library.withLibraryJar(build, dest.last.stripSuffix(".jar")) { mainJar =>
 
-        val classpath = build.fullClassPath.map(_.toString) :+ mainJar.toString()
+        val classpath = build.fullClassPath.map(_.toString) :+ mainJar.toString
         val args =
           cliOptions ++
             logger.scalaNativeCliInternalLoggerOptions ++