Add Scala 3 support

.github/workflows/ci.yml

@@ -23,7 +23,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.12.17, 2.13.10]
+        scala: [2.12.17, 2.13.10, 3.3.0]
         java: [temurin@8, temurin@11, temurin@17]
     runs-on: ${{ matrix.os }}
     steps:
@@ -158,6 +158,16 @@ jobs:
           tar xf targets.tar
           rm targets.tar
 
+      - name: Download target directories (3.3.0)
+        uses: actions/download-artifact@v2
+        with:
+          name: target-${{ matrix.os }}-3.3.0-${{ matrix.java }}
+
+      - name: Inflate target directories (3.3.0)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
       - name: Publish project
         env:
           PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}

build.sbt

@@ -4,6 +4,7 @@ name := "pekko-streams-circe"
 
 val scala213Version = "2.13.10"
 val scala212Version = "2.12.17"
+val scala3Version   = "3.3.0"
 
 ThisBuild / resolvers += Resolver.ApacheMavenSnapshotsRepo
 
@@ -13,8 +14,8 @@ val pekkoHttpVersion = "0.0.0+4411-6fe04045-SNAPSHOT"
 val jawnVersion      = "1.5.0"
 val scalaTestVersion = "3.2.16"
 
-ThisBuild / crossScalaVersions   := Seq(scala212Version, scala213Version)
-ThisBuild / scalaVersion         := (ThisBuild / crossScalaVersions).value.last
+ThisBuild / crossScalaVersions   := Seq(scala212Version, scala213Version, scala3Version)
+ThisBuild / scalaVersion         := scala213Version
 ThisBuild / organization         := "org.mdedetrich"
 ThisBuild / mimaFailOnNoPrevious := false // Set this to true when we start caring about binary compatibility
 ThisBuild / versionScheme        := Some(VersionScheme.EarlySemVer)
@@ -94,10 +95,6 @@ ThisBuild / scalacOptions ++= Seq(
   "-deprecation", // warning and location for usages of deprecated APIs
   "-feature",     // warning and location for usages of features that should be imported explicitly
   "-unchecked",   // additional warnings where generated code depends on assumptions
-  "-Xlint",       // recommended additional warnings
-  "-Xcheckinit", // runtime error when a val is not initialized due to trait hierarchies (instead of NPE somewhere else)
-  "-Ywarn-value-discard", // Warn when non-Unit expression results are unused
-  "-Ywarn-dead-code",
   "-language:postfixOps"
 )
 
@@ -125,26 +122,36 @@ ThisBuild / pomIncludeRepository   := (_ => false)
 
 val flagsFor12 = Seq(
   "-Xlint:_",
+  "-Xcheckinit", // runtime error when a val is not initialized due to trait hierarchies (instead of NPE somewhere else)
   "-Ywarn-infer-any",
   "-Ywarn-adapted-args", // Warn if an argument list is modified to match the receiver
   "-Ywarn-inaccessible",
   "-Ywarn-infer-any",
+  "-Ywarn-value-discard", // Warn when non-Unit expression results are unused
+  "-Ywarn-dead-code",
   "-opt-inline-from:<sources>",
   "-opt:l:inline"
 )
 
 val flagsFor13 = Seq(
   "-Xlint:_",
+  "-Xcheckinit", // runtime error when a val is not initialized due to trait hierarchies (instead of NPE somewhere else)
+  "-Ywarn-value-discard", // Warn when non-Unit expression results are unused
+  "-Ywarn-dead-code",
   "-opt-inline-from:<sources>",
   "-opt:l:inline"
 )
 
+val flagsFor3 = Seq.empty
+
 ThisBuild / scalacOptions ++= {
   CrossVersion.partialVersion(scalaVersion.value) match {
     case Some((2, n)) if n == 13 =>
       flagsFor13
     case Some((2, n)) if n == 12 =>
       flagsFor12
+    case Some((3, _)) =>
+      Seq.empty
   }
 }