Update scala3-library to 3.3.9

project/Common.scala

@@ -76,7 +76,6 @@ object Common extends AutoPlugin {
     scalacOptions ++= onlyOnScala33(Seq("-Yfuture-lazy-vals")).value,
     javacOptions ++=
       Seq("-encoding", "UTF-8", "--release", javacTarget),
-    mimaReportSignatureProblems := true,
     Compile / doc / scalacOptions --= Seq("-Xfatal-warnings"),
     Global / parallelExecution := sys.props.getOrElse("pekko.http.parallelExecution", "true") != "false")
 
@@ -99,3 +98,15 @@ object Common extends AutoPlugin {
   def scalaMinorVersion: Def.Initialize[Long] = Def.setting { CrossVersion.partialVersion(scalaVersion.value).get._2 }
 
 }
+
+/**
+ * Scala 3 emits different generic signatures than Scala 2.13 (and they change between
+ * Scala 3 patch releases), so only report signature problems for Scala 2.13.
+ * Requires the sbt-pekko-build MiMa plugin so that this overrides its `mimaReportSignatureProblems := true`.
+ */
+object MiMaSignatureProblems extends AutoPlugin {
+  override def requires = com.github.pjfanning.pekkobuild.MiMa
+  override def trigger: PluginTrigger = allRequirements
+  override lazy val projectSettings = Seq(
+    mimaReportSignatureProblems := !scalaVersion.value.startsWith("3"))
+}

project/Dependencies.scala

@@ -37,7 +37,7 @@ object Dependencies {
   val scalafixVersion = _root_.scalafix.sbt.BuildInfo.scalafixVersion // grab from plugin
 
   val scala213Version = "2.13.18"
-  val scala3Version = "3.3.8"
+  val scala3Version = "3.3.9"
   val scala3NextVersion = "3.9.0"
   val publishedScalaVersions = Seq(scala213Version, scala3Version)
 

project/ValidatePullRequest.scala

@@ -586,6 +586,11 @@ object MimaWithPrValidation extends AutoPlugin {
           (stringWriter.toString, result)
         }
 
+        val reportSignatureProblems = mimaReportSignatureProblems.value
+        def reportable(problems: List[core.Problem]): List[core.Problem] =
+          if (reportSignatureProblems) problems
+          else problems.filterNot(_.isInstanceOf[core.IncompatibleSignatureProblem])
+
         val allResults =
           mimaPreviousClassfiles.value.toSeq.map {
             case (moduleId, file) =>
@@ -605,7 +610,7 @@ object MimaWithPrValidation extends AutoPlugin {
               withLogger { logger =>
                 reportModuleErrors(
                   moduleId,
-                  problems._1, problems._2,
+                  reportable(problems._1), reportable(problems._2),
                   binary,
                   backward,
                   forward,