Upgrade to Scala v2.13

Key challenges with the upgrade:

* The [`scala-io`](https://github.com/jesseeichar/scala-io) library is not
  available for Scala 2.13 (I had custom-built the Scala 2.12 version, but it
  was too much effort to get it to 2.13). `scala-io` was providing several
  useful features:
  * streaming reading of character data with line-splitting that *preserves
    line-breaks* (because I don't want the BFG to change the line-breaks in
    your files while doing `--replace-text`). Finding a replacement library to
    do this wasn't easy - so much code seems to be based on
    `java.io.BufferedReader`, which throws line-breaks away. `java.util.Scanner`    can _maybe_ do it, but I couldn't get it to work! In the end, I implemented
    my own solution, a tiny library with a fairly decent set of tests:
    https://github.com/rtyley/line-break-preserving-line-splitting
  * resource management - mostly replaced by using Scala 2.13's
    [`Using`](https://www.scala-lang.org/api/current/scala/util/Using$.html).
  * File-path types and operations - mostly now performed by java.nio & Guava
    functions.
* Scala 2.13 has a [revised collections framework](https://docs.scala-lang.org/overviews/core/collections-migration-213.html), so:
  * BFG has its own `ConcurrentSet` which needs to be implemented in the new
    fashion
  * `Traversable` becomes `Iterable`, etc

Author: rtyley

.travis.yml

@@ -1,7 +1,7 @@
 language: scala
 dist: xenial
 scala:
-   - 2.12.12
+   - 2.13.4
 
 jdk:
   - openjdk8

bfg-benchmark/build.sbt

@@ -1,8 +1,7 @@
 import Dependencies._
 
-libraryDependencies ++= Seq(
+libraryDependencies ++= guava ++ Seq(
   madgagCompress,
-  scalaIoFile,
   textmatching,
   scopt
 )

bfg-benchmark/src/main/scala/Benchmark.scala

@@ -2,12 +2,13 @@ import lib.Timing.measureTask
 import lib._
 import model._
 
+import java.nio.file.Files
+import java.nio.file.Files.isDirectory
 import scala.concurrent.ExecutionContext.Implicits.global
 import scala.concurrent._
 import scala.concurrent.duration.Duration
+import scala.jdk.StreamConverters._
 import scala.sys.process._
-import scalax.file.PathMatcher.IsDirectory
-import scalax.io.Codec
 
 /*
  * Vary BFG runs by:
@@ -17,24 +18,22 @@ import scalax.io.Codec
  */
 object Benchmark extends App {
 
-  implicit val codec = Codec.UTF8
-
   BenchmarkConfig.parser.parse(args, BenchmarkConfig()) map {
     config =>
-      println(s"Using resources dir : ${config.resourcesDir.path}")
+      println(s"Using resources dir : ${config.resourcesDir}")
 
-      require(config.resourcesDir.exists, s"Resources dir not found : ${config.resourcesDir.path}")
-      require(config.jarsDir.exists, s"Jars dir not found : ${config.jarsDir.path}")
-      require(config.reposDir.exists, s"Repos dir not found : ${config.reposDir.path}")
+      require(Files.exists(config.resourcesDir), s"Resources dir not found : ${config.resourcesDir}")
+      require(Files.exists(config.jarsDir), s"Jars dir not found : ${config.jarsDir}")
+      require(Files.exists(config.reposDir), s"Repos dir not found : ${config.reposDir}")
 
-      val missingJars = config.bfgJars.filterNot(_.exists).map(_.toAbsolute.path)
+      val missingJars = config.bfgJars.filterNot(Files.exists(_))
       require(missingJars.isEmpty, s"Missing BFG jars : ${missingJars.mkString(",")}")
 
       val tasksFuture = for {
         bfgInvocableEngineSet <- bfgInvocableEngineSet(config)
       } yield {
         val gfbInvocableEngineSetOpt =
-          if (config.onlyBfg) None else Some(InvocableEngineSet[GFBInvocation](GitFilterBranch, Seq(InvocableGitFilterBranch)))
+          Option.when(!config.onlyBfg)(InvocableEngineSet[GFBInvocation](GitFilterBranch, Seq(InvocableGitFilterBranch)))
         boogaloo(config, new RepoExtractor(config.scratchDir), Seq(bfgInvocableEngineSet) ++ gfbInvocableEngineSetOpt.toSeq)
       }
 
@@ -59,27 +58,24 @@ object Benchmark extends App {
   def boogaloo(config: BenchmarkConfig, repoExtractor: RepoExtractor, invocableEngineSets: Seq[InvocableEngineSet[_ <: EngineInvocation]]) = {
 
     for {
-      repoSpecDir <- config.repoSpecDirs.toList
-      availableCommandDirs = (repoSpecDir / "commands").children().filter(IsDirectory).toList
+      repoSpecDir <- config.repoSpecDirs
+      availableCommandDirs = Files.list(repoSpecDir.resolve("commands")).toScala(Seq).filter(isDirectory(_))
       // println(s"Available commands for $repoName : ${availableCommandDirs.map(_.name).mkString(", ")}")
-      commandDir <- availableCommandDirs.filter(p => config.commands(p.name))
+      commandDir <- availableCommandDirs.filter(p => config.commands(p.getFileName.toString))
     } yield {
-
-      val repoName = repoSpecDir.name
-
-      val commandName = commandDir.name
+      val commandName: String = commandDir.getFileName.toString
 
       commandName -> (for {
         invocableEngineSet <- invocableEngineSets
       } yield for {
           (invocable, processMaker) <- invocableEngineSet.invocationsFor(commandDir)
         } yield {
-        val cleanRepoDir = repoExtractor.extractRepoFrom(repoSpecDir / "repo.git.zip")
-        commandDir.children().foreach(p => p.copyTo(cleanRepoDir / p.name))
-        val process = processMaker(cleanRepoDir)
+        val cleanRepoDir = repoExtractor.extractRepoFrom(repoSpecDir.resolve("repo.git.zip"))
+        Files.list(commandDir).toScala(Seq).foreach(p => Files.copy(p, cleanRepoDir.resolve(p.getFileName)))
+        val process = processMaker(cleanRepoDir.toFile)
 
             val duration = measureTask(s"$commandName - $invocable") {
-              process ! ProcessLogger(_ => Unit)
+              process ! ProcessLogger(_ => ())
             }
 
             if (config.dieIfTaskTakesLongerThan.exists(_ < duration.toMillis)) {

bfg-benchmark/src/main/scala/BenchmarkConfig.scala

@@ -1,16 +1,13 @@
 import java.io.File
-
 import com.madgag.textmatching.{Glob, TextMatcher}
 import scopt.OptionParser
 
-import scalax.file.ImplicitConversions._
-import scalax.file.Path
-import scalax.file.defaultfs.DefaultPath
+import java.nio.file.{Path, Paths}
 
 object BenchmarkConfig {
   val parser = new OptionParser[BenchmarkConfig]("benchmark") {
     opt[File]("resources-dir").text("benchmark resources folder - contains jars and repos").action {
-      (v, c) => c.copy(resourcesDirOption = v)
+      (v, c) => c.copy(resourcesDirOption = v.toPath)
     }
     opt[String]("java").text("Java command paths").action {
       (v, c) => c.copy(javaCmds = v.split(',').toSeq)
@@ -28,27 +25,27 @@ object BenchmarkConfig {
       (v, c) => c.copy(commands = TextMatcher(v, defaultType = Glob))
     }
     opt[File]("scratch-dir").text("Temp-dir for job runs - preferably ramdisk, eg tmpfs.").action {
-      (v, c) => c.copy(scratchDir = v)
+      (v, c) => c.copy(scratchDir = v.toPath)
     }
     opt[Unit]("only-bfg") action { (_, c) => c.copy(onlyBfg = true) } text "Don't benchmark git-filter-branch"
   }
 }
-case class BenchmarkConfig(resourcesDirOption: Path = Path.fromString(System.getProperty("user.dir")) / "bfg-benchmark" / "resources",
-                           scratchDir: DefaultPath = Path.fromString("/dev/shm/"),
+case class BenchmarkConfig(resourcesDirOption: Path = Paths.get(System.getProperty("user.dir"), "bfg-benchmark", "resources"),
+                           scratchDir: Path = Paths.get("/dev/shm/"),
                            javaCmds: Seq[String] = Seq("java"),
                            bfgVersions: Seq[String] = Seq.empty,
                            commands: TextMatcher = Glob("*"),
                            onlyBfg: Boolean = false,
                            dieIfTaskTakesLongerThan: Option[Int] = None,
                            repoNames: Seq[String] = Seq.empty) {
 
-  lazy val resourcesDir = Path.fromString(resourcesDirOption.path).toAbsolute
+  lazy val resourcesDir: Path = resourcesDirOption.toAbsolutePath
 
-  lazy val jarsDir = resourcesDir / "jars"
+  lazy val jarsDir: Path = resourcesDir.resolve("jars")
 
-  lazy val reposDir = resourcesDir / "repos"
+  lazy val reposDir: Path = resourcesDir.resolve("repos")
 
-  lazy val bfgJars = bfgVersions.map(version => jarsDir / s"bfg-$version.jar")
+  lazy val bfgJars: Seq[Path] = bfgVersions.map(version => jarsDir.resolve(s"bfg-$version.jar"))
 
-  lazy val repoSpecDirs = repoNames.map(reposDir / _)
+  lazy val repoSpecDirs: Seq[Path] = repoNames.map(reposDir.resolve)
 }

bfg-benchmark/src/main/scala/lib/Repo.scala

@@ -1,23 +1,26 @@
 package lib
 
+import com.google.common.io.MoreFiles
+import com.google.common.io.RecursiveDeleteOption.ALLOW_INSECURE
 import com.madgag.compress.CompressUtil._
 
-import scalax.file.ImplicitConversions._
-import scalax.file.Path
-import scalax.file.defaultfs.DefaultPath
+import java.nio.file.{Files, Path}
+import scala.util.Using
 
-class RepoExtractor(scratchDir: DefaultPath) {
+class RepoExtractor(scratchDir: Path) {
 
-  val repoDir = scratchDir / "repo.git"
+  val repoDir = scratchDir.resolve( "repo.git")
 
   def extractRepoFrom(zipPath: Path) = {
-    repoDir.deleteRecursively(force = true)
+    if (Files.exists(repoDir)) MoreFiles.deleteRecursively(repoDir, ALLOW_INSECURE)
 
-    repoDir.createDirectory()
+    Files.createDirectories(repoDir)
 
-    println(s"Extracting repo to ${repoDir.toAbsolute.path}")
+    println(s"Extracting repo to ${repoDir.toAbsolutePath}")
 
-    zipPath.inputStream.acquireFor { stream => unzip(stream, repoDir) }
+    Using(Files.newInputStream(zipPath)) {
+      stream => unzip(stream, repoDir.toFile)
+    }
 
     repoDir
   }

bfg-benchmark/src/main/scala/model/BFGJar.scala

@@ -1,6 +1,6 @@
 package model
 
-import scalax.file.Path
+import java.nio.file.Path
 
 object BFGJar {
   def from(path: Path) = BFGJar(path, Map.empty)

bfg-benchmark/src/main/scala/model/InvocableEngine.scala

@@ -1,10 +1,13 @@
 package model
 
+import com.google.common.io.CharSource
+import com.google.common.io.Files.asCharSource
+
+import java.io.File
+import java.nio.charset.StandardCharsets.UTF_8
+import java.nio.file.{Files, Path}
+import scala.jdk.StreamConverters._
 import scala.sys.process.{Process, ProcessBuilder}
-import scalax.file.ImplicitConversions._
-import scalax.file.Path
-import scalax.file.defaultfs.DefaultPath
-import scalax.io.Input
 
 trait EngineInvocation
 
@@ -15,19 +18,19 @@ case class GFBInvocation(args: Seq[String]) extends EngineInvocation
 
 trait InvocableEngine[InvocationArgs <: EngineInvocation] {
 
-    def processFor(invocation: InvocationArgs)(repoPath: DefaultPath): ProcessBuilder
+    def processFor(invocation: InvocationArgs)(repoPath: File): ProcessBuilder
 }
 
 case class InvocableBFG(java: Java, bfgJar: BFGJar) extends InvocableEngine[BFGInvocation] {
 
-  def processFor(invocation: BFGInvocation)(repoPath: DefaultPath) =
-    Process(s"${java.javaCmd} -jar ${bfgJar.path.path} ${invocation.args}", repoPath)
+  def processFor(invocation: BFGInvocation)(repoPath: File) =
+    Process(s"${java.javaCmd} -jar ${bfgJar.path} ${invocation.args}", repoPath)
 
 }
 
 object InvocableGitFilterBranch extends InvocableEngine[GFBInvocation] {
 
-  def processFor(invocation: GFBInvocation)(repoPath: DefaultPath) =
+  def processFor(invocation: GFBInvocation)(repoPath: File) =
     Process(Seq("git", "filter-branch") ++ invocation.args, repoPath)
 }
 
@@ -42,24 +45,24 @@ We want to allow the user to vary:
 trait EngineType[InvocationType <: EngineInvocation] {
   val configName: String
 
-  def argsFor(config: Input): InvocationType
+  def argsFor(config: CharSource): InvocationType
 
   def argsOptsFor(commandDir: Path): Option[InvocationType] = {
-    val paramsPath = commandDir / s"$configName.txt"
-    if (paramsPath.exists) Some(argsFor(paramsPath)) else None
+    val paramsPath = commandDir.resolve(s"$configName.txt")
+    if (Files.exists(paramsPath)) Some(argsFor(asCharSource(paramsPath.toFile, UTF_8))) else None
   }
 }
 
 case object BFG extends EngineType[BFGInvocation] {
 
   val configName = "bfg"
 
-  def argsFor(config: Input) = BFGInvocation(config.string)
+  def argsFor(config: CharSource) = BFGInvocation(config.read())
 }
 
 case object GitFilterBranch extends EngineType[GFBInvocation] {
 
   val configName = "gfb"
 
-  def argsFor(config: Input) = GFBInvocation(config.lines().toSeq)
+  def argsFor(config: CharSource) = GFBInvocation(config.lines().toScala(Seq))
 }

bfg-benchmark/src/main/scala/model/InvocableEngineSet.scala

@@ -1,14 +1,14 @@
 package model
 
-import scalax.file.Path
-import scalax.file.defaultfs.DefaultPath
+import java.io.File
+import java.nio.file.Path
 
 case class InvocableEngineSet[InvocationArgs <: EngineInvocation](
   engineType: EngineType[InvocationArgs],
   invocableEngines: Seq[InvocableEngine[InvocationArgs]]
 ) {
 
-  def invocationsFor(commandDir: Path): Seq[(InvocableEngine[InvocationArgs], DefaultPath => scala.sys.process.ProcessBuilder)] = {
+  def invocationsFor(commandDir: Path): Seq[(InvocableEngine[InvocationArgs], File => scala.sys.process.ProcessBuilder)] = {
     for {
       args <- engineType.argsOptsFor(commandDir).toSeq
       invocable <- invocableEngines

bfg-benchmark/src/test/scala/JavaVersionSpec.scala

@@ -1,4 +1,6 @@
-import org.scalatest.{FlatSpec, Matchers, OptionValues}
+import org.scalatest.OptionValues
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
 
 object JavaVersionSpec extends AnyFlatSpec with OptionValues with Matchers {
   "version" should "parse an example line" in {

bfg-library/build.sbt

@@ -1,4 +1,14 @@
 import Dependencies._
 
-libraryDependencies ++= guava :+ scalaIoFile :+ textmatching :+ scalaGit :+ jgit :+ slf4jSimple :+ scalaGitTest % "test"
+libraryDependencies ++= guava ++ Seq(
+  parCollections,
+  scalaCollectionPlus,
+  textmatching,
+  scalaGit,
+  jgit,
+  slf4jSimple,
+  lineSplitting,
+  scalaGitTest % Test,
+  "org.apache.commons" % "commons-text" % "1.9" % Test
+)