Add scalafix

.github/workflows/ci.yml

@@ -87,6 +87,10 @@ jobs:
       - name: Setup sbt
         uses: sbt/setup-sbt@v1
 
+      - name: 'Linter: Scalafix checks'
+        shell: bash
+        run: sbt '++ ${{ matrix.scala }}' 'scalafixAll --check'
+
       - name: Install sbt
         if: matrix.os == 'macos-latest'
         shell: bash

.scalafix.conf

@@ -0,0 +1,32 @@
+rules = [
+  DisableSyntax, # Disables some constructs that make no semantic sense like `final val`
+  ProcedureSyntax, # Procedure syntax in Scala is always discouraged
+  ExplicitResultTypes, # To avoid public API breakages by mistake is good to always annotate the return types of public methods
+  NoValInForComprehension, # `val` in for comprehensions are deprecated and shouldn't be used
+  NoAutoTupling, # Avoids the automatic tupling in parameters
+  RemoveUnused, # Removes unused elements
+  LeakingImplicitClassVal, # This rule adds the private access modifier on the field of implicit value classes in order to prevent direct access.
+  OrganizeImports # Organizes imports and removes unused ones
+]
+
+ExplicitResultTypes.memberKind = [Def, Val, Var]
+ExplicitResultTypes.memberVisibility = [Public, Protected]
+ExplicitResultTypes.skipSimpleDefinitions = ['Lit', 'Term.New', 'Term.Ref']
+ExplicitResultTypes.fatalWarnings = true
+DisableSyntax.noReturns = true
+DisableSyntax.noWhileLoops = true
+DisableSyntax.noIsInstanceOf = true
+DisableSyntax.noXml = true
+DisableSyntax.noFinalVal = true
+DisableSyntax.noFinalize = true
+DisableSyntax.noValPatterns = true
+RemoveUnused.imports = false # The plugin organize imports removes unused and clashes with this
+OrganizeImports {
+  groupedImports = Merge
+  groups = [
+    "*",
+    "java.",
+    "scala.",
+    "re:javax?\\."
+  ] # Reasoning for this config is to keep the more business related imports at the top, while language imports are on the bottom
+}

build.sbt

@@ -192,6 +192,10 @@ ThisBuild / githubWorkflowPublish := Seq(
   )
 )
 
+ThisBuild / githubWorkflowBuildPreamble := Seq(
+  WorkflowStep.Sbt(List("scalafixAll --check"), name = Some("Linter: Scalafix checks"))
+)
+
 ThisBuild / githubWorkflowTargetTags ++= Seq("v*")
 ThisBuild / githubWorkflowPublishTargetBranches :=
   Seq(
@@ -221,3 +225,15 @@ ThisBuild / githubWorkflowBuildPreamble ++= Seq(
     name = Some("Install sbt")
   )
 )
+
+// scalafix specific settings
+inThisBuild(
+  List(
+    semanticdbEnabled          := true,
+    semanticdbVersion          := scalafixSemanticdb.revision,
+    scalafixScalaBinaryVersion := scalaBinaryVersion.value,
+    scalacOptions ++= Seq(
+      "-Ywarn-unused"
+    )
+  )
+)

http-json/src/main/scala/org/mdedetrich/pekko/http/JsonSupport.scala

@@ -18,17 +18,18 @@
 package org.mdedetrich.pekko.http
 
 import org.apache.pekko
+import org.mdedetrich.pekko.json.stream.JsonStreamParser
+import org.typelevel.jawn.Facade
+
+import scala.concurrent.{Future, Promise}
+
 import pekko.http.scaladsl.model.HttpEntity
 import pekko.http.scaladsl.model.MediaTypes.`application/json`
 import pekko.http.scaladsl.unmarshalling.{FromEntityUnmarshaller, Unmarshaller}
 import pekko.http.scaladsl.util.FastFuture
 import pekko.stream._
 import pekko.stream.scaladsl.Sink
 import pekko.stream.stage._
-import org.mdedetrich.pekko.json.stream.JsonStreamParser
-import org.typelevel.jawn.Facade
-
-import scala.concurrent.{Future, Promise}
 
 trait JsonSupport {
 

project/plugins.sbt

@@ -8,3 +8,4 @@ addSbtPlugin("org.scoverage"                     % "sbt-coveralls"      % "1.3.1
 addSbtPlugin("com.typesafe"                      % "sbt-mima-plugin"    % "1.1.4")
 addSbtPlugin("com.github.sbt"                    % "sbt-github-actions" % "0.24.0")
 addSbtPlugin("ch.epfl.scala"                     % "sbt-version-policy" % "3.2.1")
+addSbtPlugin("ch.epfl.scala"                     % "sbt-scalafix"       % "0.13.0")

stream-json/src/main/scala/org/mdedetrich/pekko/json/stream/JsonStreamParser.scala

@@ -18,20 +18,22 @@
 package org.mdedetrich.pekko.json.stream
 
 import org.apache.pekko
-import pekko.NotUsed
-import pekko.stream.Attributes.name
-import pekko.stream.scaladsl.{Flow, Keep, Sink}
-import pekko.stream.stage.{GraphStage, GraphStageLogic, InHandler, OutHandler}
-import pekko.stream._
-import pekko.util.ByteString
 import org.typelevel.jawn.AsyncParser.ValueStream
 import org.typelevel.jawn._
 
+import java.nio.ByteBuffer
+
 import scala.annotation.tailrec
 import scala.collection.mutable.ArrayBuffer
 import scala.concurrent.Future
 import scala.util.Try
-import java.nio.ByteBuffer
+
+import pekko.NotUsed
+import pekko.stream.Attributes.name
+import pekko.stream.scaladsl.{Flow, Keep, Sink}
+import pekko.stream.stage.{GraphStage, GraphStageLogic, InHandler, OutHandler}
+import pekko.stream._
+import pekko.util.ByteString
 
 object JsonStreamParser {
 
@@ -132,9 +134,9 @@ object JsonStreamParser {
 
 final class JsonStreamParser[J: Facade] private (mode: AsyncParser.Mode, multiValue: Boolean)
     extends GraphStage[FlowShape[ByteString, J]] {
-  private[this] val in  = Inlet[ByteString]("Json.in")
-  private[this] val out = Outlet[J]("Json.out")
-  override val shape    = FlowShape(in, out)
+  private[this] val in                         = Inlet[ByteString]("Json.in")
+  private[this] val out                        = Outlet[J]("Json.out")
+  override val shape: FlowShape[ByteString, J] = FlowShape(in, out)
   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic =
     new JsonStreamParser.ParserLogic[J](AsyncParser[J](mode, multiValue), shape)
 }

support/http-circe/src/main/scala/org/mdedetrich/pekko/http/support/CirceHttpSupport.scala

@@ -17,16 +17,16 @@
 
 package org.mdedetrich.pekko.http.support
 
-import org.apache.pekko
-import pekko.http.scaladsl.marshalling.{Marshaller, ToEntityMarshaller}
-import pekko.http.scaladsl.model.MediaTypes.`application/json`
-import pekko.http.scaladsl.unmarshalling.FromEntityUnmarshaller
 import io.circe.jawn.CirceSupportParser._
 import io.circe.{Decoder, Encoder, Json, Printer}
-
+import org.apache.pekko
 import org.mdedetrich.pekko.http.JsonSupport
 import org.mdedetrich.pekko.stream.support.CirceStreamSupport
 
+import pekko.http.scaladsl.marshalling.{Marshaller, ToEntityMarshaller}
+import pekko.http.scaladsl.model.MediaTypes.`application/json`
+import pekko.http.scaladsl.unmarshalling.FromEntityUnmarshaller
+
 trait CirceHttpSupport extends JsonSupport {
 
   implicit def circeJsonUnmarshaller: FromEntityUnmarshaller[Json] =

support/stream-circe/src/main/scala/org/mdedetrich/pekko/stream/support/CirceStreamSupport.scala

@@ -18,16 +18,17 @@
 package org.mdedetrich.pekko.stream
 package support
 
-import org.apache.pekko
-import pekko.NotUsed
-import pekko.stream.scaladsl.Flow
-import pekko.util.ByteString
 import io.circe.CursorOp.DownField
-import io.circe.jawn.CirceSupportParser._
 import io.circe._
+import io.circe.jawn.CirceSupportParser._
+import org.apache.pekko
 import org.mdedetrich.pekko.json.stream.JsonStreamParser
 import org.typelevel.jawn.AsyncParser
 
+import pekko.NotUsed
+import pekko.stream.scaladsl.Flow
+import pekko.util.ByteString
+
 trait CirceStreamSupport {
 
   def decode[A: Decoder]: Flow[ByteString, A, NotUsed] =

tests/src/test/scala/org/mdedetrich/pekko/http/JsonSupportSpec.scala

@@ -17,17 +17,9 @@
 
 package org.mdedetrich.pekko.http
 
-import org.apache.pekko
-import pekko.actor.ActorSystem
-import pekko.http.scaladsl.marshalling.Marshal
-import pekko.http.scaladsl.model.HttpCharsets.`UTF-8`
-import pekko.http.scaladsl.model.MediaTypes.`application/json`
-import pekko.http.scaladsl.model.{HttpEntity, RequestEntity, UniversalEntity}
-import pekko.http.scaladsl.unmarshalling.Unmarshal
-import pekko.stream.scaladsl.{Keep, Sink, Source}
-import pekko.util.ByteString
 import io.circe.generic.semiauto._
 import io.circe.{Decoder, Encoder, Printer}
+import org.apache.pekko
 import org.mdedetrich.pekko.http.support.CirceHttpSupport
 import org.mdedetrich.pekko.stream.support.CirceStreamSupport
 import org.scalatest._
@@ -38,6 +30,15 @@ import org.typelevel.jawn.{AsyncParser, ParseException}
 import scala.concurrent.Await
 import scala.concurrent.duration._
 
+import pekko.actor.ActorSystem
+import pekko.http.scaladsl.marshalling.Marshal
+import pekko.http.scaladsl.model.HttpCharsets.`UTF-8`
+import pekko.http.scaladsl.model.MediaTypes.`application/json`
+import pekko.http.scaladsl.model.{HttpEntity, RequestEntity, UniversalEntity}
+import pekko.http.scaladsl.unmarshalling.Unmarshal
+import pekko.stream.scaladsl.{Keep, Sink, Source}
+import pekko.util.ByteString
+
 case class Foo(bar: String, baz: Int, qux: List[Boolean])
 object Foo {
   implicit val decoderFoo: Decoder[Foo] = deriveDecoder
@@ -56,15 +57,15 @@ class JsonSupportSpec
     with Matchers
     with BeforeAndAfterAll {
 
-  val foo            = Foo("bar", 42, List(true, false))
-  val goodJson       = """{"bar":"bar","baz":42,"qux":[true,false]}"""
-  val incompleteJson = """{"bar":"bar","baz":42,"qux"""
-  val badJson        = """{"bar":"bar"}"""
-  val badBarJson     = """{"foo":{"bar":"bar"}}"""
-  val wrongJson      = """{"bar":"bar","baz":"forty two","qux":[]}"""
-  val wrongBarJson   = """{"foo":{"bar":"bar","baz":"forty two","qux":[]}}"""
-  val invalidJson    = """{"bar"="bar"}"""
-  val prettyJson =
+  val foo: Foo               = Foo("bar", 42, List(true, false))
+  val goodJson: String       = """{"bar":"bar","baz":42,"qux":[true,false]}"""
+  val incompleteJson: String = """{"bar":"bar","baz":42,"qux"""
+  val badJson: String        = """{"bar":"bar"}"""
+  val badBarJson: String     = """{"foo":{"bar":"bar"}}"""
+  val wrongJson: String      = """{"bar":"bar","baz":"forty two","qux":[]}"""
+  val wrongBarJson: String   = """{"foo":{"bar":"bar","baz":"forty two","qux":[]}}"""
+  val invalidJson: String    = """{"bar"="bar"}"""
+  val prettyJson: String =
     """
       |{
       |  "bar" : "bar",