Compile with Scala 3

build.sbt

@@ -42,24 +42,24 @@ lazy val cliMainClass = Seq(
 )
 
 lazy val compileOptions: Seq[Setting[_]] = Seq(
-  scalacOptions ++= Seq("-Xfatal-warnings", "-deprecation", "-Xsource:3")
+  scalacOptions ++= Seq("-Xfatal-warnings", "-deprecation")
 )
 
 lazy val packagerProjectSettings = Seq(
   name               := "scala-packager",
-  scalaVersion       := ScalaVersions.scala213,
+  scalaVersion       := ScalaVersions.scala3,
   crossScalaVersions := ScalaVersions.all
 )
 
 lazy val imageResizerProjectSettings = Seq(
   name               := "scala-packager-image-resizer",
-  scalaVersion       := ScalaVersions.scala213,
+  scalaVersion       := ScalaVersions.scala3,
   crossScalaVersions := ScalaVersions.all
 )
 
 lazy val cliProjectSettings = Seq(
   name               := "scala-packager-cli",
-  scalaVersion       := ScalaVersions.scala213,
+  scalaVersion       := ScalaVersions.scala3,
   crossScalaVersions := ScalaVersions.all,
   libraryDependencies ++= Seq(Deps.caseApp)
 )

modules/cli/src/main/scala/packager/cli/commands/BuildOptions.scala

@@ -1,6 +1,6 @@
 package packager.cli.commands
 
-import caseapp.{Group, HelpMessage, Name, Parser, Recurse}
+import caseapp._
 import caseapp.core.help.Help
 import packager.cli.commands.BuildOptions.PackagerType
 import packager.config._
@@ -107,6 +107,6 @@ object BuildOptions {
     case object Rpm    extends NativePackagerType
   }
 
-  implicit val parser: Parser[BuildOptions] = Parser[BuildOptions]
-  implicit val help: Help[BuildOptions]     = Help[BuildOptions]
+  implicit lazy val parser: Parser[BuildOptions] = Parser.derive
+  implicit lazy val help: Help[BuildOptions]     = Help.derive
 }

modules/cli/src/main/scala/packager/cli/commands/DebianOptions.scala

@@ -1,7 +1,7 @@
 package packager.cli.commands
 
+import caseapp._
 import caseapp.core.help.Help
-import caseapp.{Group, HelpMessage, Parser, ValueDescription}
 import packager.cli.commands.SettingsHelpers.Mandatory
 import packager.config.{DebianSettings, SharedSettings}
 
@@ -54,8 +54,6 @@ final case class DebianOptions(
 }
 
 case object DebianOptions {
-
-  implicit val parser: Parser[DebianOptions] = Parser[DebianOptions]
-  implicit val help: Help[DebianOptions]     = Help[DebianOptions]
-
+  implicit lazy val parser: Parser[DebianOptions] = Parser.derive
+  implicit lazy val help: Help[DebianOptions]     = Help.derive
 }

modules/cli/src/main/scala/packager/cli/commands/DockerOptions.scala

@@ -1,7 +1,7 @@
 package packager.cli.commands
 
+import caseapp._
 import caseapp.core.help.Help
-import caseapp.{Group, HelpMessage, Parser, ValueDescription}
 import packager.cli.commands.SettingsHelpers.Mandatory
 import packager.config.DockerSettings
 import java.nio.file.Path;
@@ -57,8 +57,6 @@ final case class DockerOptions(
 }
 
 case object DockerOptions {
-
-  implicit val parser: Parser[DockerOptions] = Parser[DockerOptions]
-  implicit val help: Help[DockerOptions]     = Help[DockerOptions]
-
+  implicit lazy val parser: Parser[DockerOptions] = Parser.derive
+  implicit lazy val help: Help[DockerOptions]     = Help.derive
 }

modules/cli/src/main/scala/packager/cli/commands/MacOSOptions.scala

@@ -1,6 +1,6 @@
 package packager.cli.commands
 
-import caseapp.{Group, HelpMessage, Parser}
+import caseapp._
 import caseapp.core.help.Help
 import packager.config.{MacOSSettings, SharedSettings}
 import SettingsHelpers._
@@ -22,8 +22,6 @@ final case class MacOSOptions(
 }
 
 case object MacOSOptions {
-
-  implicit val parser: Parser[MacOSOptions] = Parser[MacOSOptions]
-  implicit val help: Help[MacOSOptions]     = Help[MacOSOptions]
-
+  implicit lazy val parser: Parser[MacOSOptions] = Parser.derive
+  implicit lazy val help: Help[MacOSOptions]     = Help.derive
 }

modules/cli/src/main/scala/packager/cli/commands/RedHatOptions.scala

@@ -1,6 +1,6 @@
 package packager.cli.commands
 
-import caseapp.{Group, HelpMessage, Parser}
+import caseapp._
 import caseapp.core.help.Help
 import packager.config.{RedHatSettings, SharedSettings}
 import SettingsHelpers._
@@ -40,8 +40,6 @@ final case class RedHatOptions(
 }
 
 case object RedHatOptions {
-
-  implicit val parser: Parser[RedHatOptions] = Parser[RedHatOptions]
-  implicit val help: Help[RedHatOptions]     = Help[RedHatOptions]
-
+  implicit lazy val parser: Parser[RedHatOptions] = Parser.derive
+  implicit lazy val help: Help[RedHatOptions]     = Help.derive
 }

modules/cli/src/main/scala/packager/cli/commands/SharedOptions.scala

@@ -1,6 +1,6 @@
 package packager.cli.commands
 
-import caseapp.{Group, HelpMessage, Name, Parser, ValueDescription}
+import caseapp._
 import caseapp.core.help.Help
 
 final case class SharedOptions(
@@ -32,7 +32,6 @@ final case class SharedOptions(
   logoPath: Option[String] = None
 )
 case object SharedOptions {
-
-  implicit val parser: Parser[SharedOptions] = Parser[SharedOptions]
-  implicit val help: Help[SharedOptions]     = Help[SharedOptions]
+  implicit lazy val parser: Parser[SharedOptions] = Parser.derive
+  implicit lazy val help: Help[SharedOptions]     = Help.derive
 }

modules/cli/src/main/scala/packager/cli/commands/WindowsOptions.scala

@@ -63,6 +63,6 @@ final case class WindowsOptions(
 
 case object WindowsOptions {
 
-  implicit val parser: Parser[WindowsOptions] = Parser[WindowsOptions]
-  implicit val help: Help[WindowsOptions]     = Help[WindowsOptions]
+  implicit lazy val parser: Parser[WindowsOptions] = Parser.derive
+  implicit lazy val help: Help[WindowsOptions]     = Help.derive
 }

project/ScalaVersions.scala

@@ -1,5 +1,6 @@
 object ScalaVersions {
   def scala212 = "2.12.20"
   def scala213 = "2.13.15"
-  def all      = Seq(scala213, scala212)
+  def scala3   = "3.3.4" // we stick to the LTS here
+  def all      = Seq(scala3)
 }