Exempt scala-actors-migration from version checks.

Fixes #1818.

ivy/src/main/scala/sbt/IvyScala.scala

@@ -66,7 +66,11 @@ private object IvyScala {
       {
         val id = dep.getDependencyRevisionId
         val depBinaryVersion = CrossVersion.binaryScalaVersion(id.getRevision)
-        val mismatched = id.getOrganisation == Organization && depBinaryVersion != scalaBinaryVersion && dep.getModuleConfigurations.exists(configSet)
+        def isScalaLangOrg = id.getOrganisation == Organization
+        def isNotScalaActorsMigration = !(id.getName startsWith "scala-actors-migration") // Exception to the rule: sbt/sbt#1818
+        def hasBinVerMismatch = depBinaryVersion != scalaBinaryVersion
+        def matchesOneOfTheConfigs = dep.getModuleConfigurations.exists(configSet)
+        val mismatched = isScalaLangOrg && isNotScalaActorsMigration && hasBinVerMismatch && matchesOneOfTheConfigs
         if (mismatched)
           Some("Binary version (" + depBinaryVersion + ") for dependency " + id +
             "\n\tin " + module.getModuleRevisionId +
@@ -111,4 +115,4 @@ private object IvyScala {
       configurationNames.foreach(rule.addConfiguration)
       rule
     }
-}
+}

notes/0.13.8.markdown

@@ -39,6 +39,7 @@
   [1787]: https://github.com/sbt/sbt/pull/1787
   [1793]: https://github.com/sbt/sbt/pull/1793
   [1817]: https://github.com/sbt/sbt/pull/1817
+  [1818]: https://github.com/sbt/sbt/pull/1818
   [1869]: https://github.com/sbt/sbt/issues/1869
   [1871]: https://github.com/sbt/sbt/pull/1871
 
@@ -75,6 +76,7 @@
 - Issues warning if multiple dependencies to a same library is found with different version. [#1634][1634] by [@eed3si9n][@eed3si9n]
 - Removes "No main class detected" warning. [#1766][1766] by [@eed3si9n][@eed3si9n]
 - Disable publishing on implicitly created root project by not enabling `IvyPlugin` by default (`-Dsbt.root.ivyplugin=true` will revert this behavior). [#1871][1871]/[#1869][1869] by [@dwijnand][@dwijnand] 
+- Exempt org.scala-lang:scala-actors-migration from scala binary version checks. [#1818][1818] by [@dwijnand][@dwijnand]
 
 ### Rolling back XML parsing workaround
 

sbt/src/sbt-test/dependency-management/actors-migration-no-warn/build.sbt

@@ -0,0 +1,13 @@
+// https://github.com/sbt/sbt/issues/1818
+
+scalaVersion := "2.11.5"
+libraryDependencies += "org.scala-lang" %% "scala-actors-migration" % "1.1.0"
+
+lazy val check = taskKey[Unit]("Runs the check")
+check := {
+  val lastLog = BuiltinCommands lastLogFile state.value
+  val last = IO read lastLog.get
+  def containsWarn1 = last contains "Binary version (1.1.0) for dependency org.scala-lang#scala-actors-migration_2.11;1.1.0"
+  def containsWarn2 = last contains "differs from Scala binary version in project (2.11)."
+  if (containsWarn1 && containsWarn2) sys error "scala-actors-migration isn't exempted from the Scala binary version check"
+}

sbt/src/sbt-test/dependency-management/actors-migration-no-warn/test

@@ -0,0 +1,2 @@
+> update
+> check