Maintenance toolchain update 2023 (#159)

* Update sbt version
* Set Scala to 2.12.18 
* Fix all warnings
* Fix deprecations
* Explicit type annotation instead of type inference 
* Plugins update
* Apply new scalafmt version
* Add .ds_store to ignore

.gitignore

@@ -18,3 +18,7 @@ project/metals.sbt
 # for personal trials / tests that shall be ignored but stay on your disk
 ztest/
 .bsp/
+
+# OS specific
+.DS_Store
+

.scalafix.conf

@@ -0,0 +1,7 @@
+rules = [
+  ProcedureSyntax,
+  ExplicitResultTypes,
+  NoAutoTupling,
+  OrganizeImports,
+  RemoveUnused
+]

.scalafmt.conf

@@ -1,2 +1,2 @@
-version = 3.0.6
+version = 3.7.15
 runner.dialect = scala213

build.sbt

@@ -1,11 +1,21 @@
 import sbtassembly.AssemblyPlugin.defaultUniversalScript
 
-ThisBuild / scalaVersion := "2.13.6"
+ThisBuild / scalaVersion := "2.12.18"
 ThisBuild / organization := "com.github.cross-language-cpp"
 
+ThisBuild / semanticdbEnabled := true // enable SemanticDB
+ThisBuild / semanticdbVersion := scalafixSemanticdb.revision // use Scalafix compatible version
+
+// Keep this as a reminder, we will use that later
+// ThisBuild / scalacOptions += "-Ywarn-unused"
+// us: sbt 'set ThisBuild / scalacOptions += "-Ywarn-unused"' scalafix
+// until the last 2 unused warnings are fixed
+ThisBuild / scalacOptions ++= Seq("-deprecation", "-unchecked")
+
 val binExt = if (System.getProperty("os.name").startsWith("Windows")) ".bat" else ""
 lazy val djinni = (project in file("."))
   .configs(IntegrationTest)
+  .enablePlugins(ScalafixPlugin) // enable Scalafix for this project
   .settings(
     name := "djinni",
     Defaults.itSettings,
@@ -15,8 +25,12 @@ lazy val djinni = (project in file("."))
     libraryDependencies += "org.yaml" % "snakeyaml" % "1.29",
     libraryDependencies += "com.github.scopt" %% "scopt" % "4.0.1",
     libraryDependencies += "commons-io" % "commons-io" % "2.11.0",
-    assembly / assemblyOutputPath := { file("target/bin") / s"${(assembly / assemblyJarName).value}${binExt}" },
+    assembly / assemblyOutputPath := {
+      val dir = file("target/bin")
+      IO.createDirectory(dir)
+      dir / s"${(assembly / assemblyJarName).value}${binExt}"
+    },
     assembly / assemblyJarName := s"${name.value}",
-    assembly / assemblyOption := (assembly / assemblyOption).value.copy(prependShellScript = Some(defaultUniversalScript(shebang = false))),
+    assembly / assemblyPrependShellScript := Some(defaultUniversalScript(shebang = false)),
     assembly / test := {}
   )

project/build.properties

@@ -1 +1 @@
-sbt.version=1.5.5
+sbt.version=1.9.7

project/plugins.sbt

@@ -1,3 +1,5 @@
-addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.15.0")
-addSbtPlugin("com.dwijnand" % "sbt-dynver" % "4.1.1")
-addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.4")
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.1.4")
+addSbtPlugin("com.github.sbt" % "sbt-dynver" % "5.0.1")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.11.1")
+addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.6.3")

src/it/scala/djinni/GeneratorIntegrationTest.scala

@@ -732,23 +732,23 @@ class GeneratorIntegrationTest extends IntegrationTest with GivenWhenThen {
     }
 
     it(s"skip-generate should not generate any files") {
-      var idlFile = "all_datatypes"
-      var outputPath = "src/it/resources/result/skip_generate"
+      val idlFile = "all_datatypes"
+      val outputPath = "src/it/resources/result/skip_generate"
       Given(s"`$idlFile.djinni`")
       When(s"passing skip-generation true")
 
       djinni(djinniParams(idlFile, outputPath) + " --skip-generation true")
 
       Then(s"`$outputPath` should have been created")
-      var dir = new java.io.File(outputPath, idlFile)
+      val dir = new java.io.File(outputPath, idlFile)
       dir.exists should be(true)
 
       Then(s"genreated-files.txt should have been generated")
       val gen = new java.io.File(dir, "generated-files.txt")
       gen.exists should be(true)
 
       Then(s"only the generated-files.txt should be generated")
-      var files = dir.listFiles()
+      val files = dir.listFiles()
       files should contain only (gen)
     }
 
@@ -815,7 +815,7 @@ class GeneratorIntegrationTest extends IntegrationTest with GivenWhenThen {
     When(
       "calling the generator with `--cpp-namespace custom_namespace, --cpp-json-serialization nlohmann_json and --cpp-out`"
     )
-    val output = djinni(
+    val _ = djinni(
       s"--idl src/it/resources/${idlFile}.djinni --cpp-namespace custom_namespace --cpp-json-serialization nlohmann_json --cpp-out $outputPath/cpp --cpp-header-out $outputPath/cpp-headers"
     )
     Then(

src/it/scala/djinni/IntegrationTest.scala

@@ -10,7 +10,7 @@ import scala.sys.process._
 
 import scala.reflect.io.Directory
 import java.io.File
-import java.nio.file.Paths
+//import java.nio.file.Paths
 
 // Base class for integration tests, providing a few handy helper functions
 class IntegrationTest extends AnyFunSpec {

src/main/scala/djinni/BaseObjcGenerator.scala

@@ -41,7 +41,7 @@ abstract class BaseObjcGenerator(spec: Spec) extends Generator(spec) {
       consts: Seq[Const],
       selfName: String,
       genType: ObjcConstantType.Value
-  ) = {
+  ): Unit = {
     def boxedPrimitive(ty: TypeRef): String = {
       val (_, needRef) = marshal.toObjcType(ty)
       if (needRef) "@" else ""
@@ -78,16 +78,16 @@ abstract class BaseObjcGenerator(spec: Spec) extends Generator(spec) {
         }
       }
 
-    def writeObjcConstMethImpl(c: Const, w: IndentWriter) {
+    def writeObjcConstMethImpl(c: Const, w: IndentWriter): Unit = {
       val label = "+"
       val nullability = marshal.nullability(c.ty.resolved).fold("")(" __" + _)
       val ret = marshal.fqFieldType(c.ty) + nullability
       val decl = s"$label ($ret)${idObjc.method(c.ident)}"
-      writeAlignedObjcCall(w, decl, List(), "", p => ("", ""))
+      writeAlignedObjcCall(w, decl, List(), "", _ => ("", ""))
       w.wl
 
       w.braced {
-        var static_var = s"s_${idObjc.method(c.ident)}"
+        val static_var = s"s_${idObjc.method(c.ident)}"
         w.w(s"static ${marshal.fqFieldType(c.ty)} const ${static_var} = ")
         writeObjcConstValue(w, c.ty, c.value)
         w.wl(";")