1 files changed, 95 insertions, 0 deletions
diff --git a/project/MiMa.scala b/project/MiMa.scala
new file mode 100644
index 0000000000..66442fc725
--- /dev/null
+++ b/project/MiMa.scala
@@ -0,0 +1,95 @@
+// It would be nice to use sbt-mima-plugin here, but the plugin is missing
+// at least two features we need:
+// * ability to run MiMa twice, swapping `curr` and `prev`, to detect
+//   both forwards and backwards incompatibilities (possibly fixed as of
+//   https://github.com/typesafehub/migration-manager/commit/2844ffa48b6d2255aa64bd687703aec21dadd55e)
+// * ability to pass a filter file (https://github.com/typesafehub/migration-manager/issues/102)
+// So we invoke the MiMa CLI directly; it's also what the Ant build did.
+
+import sbt._
+import sbt.Keys._
+import BuildSettings.autoImport._
+
+object MiMa {
+  lazy val mima =
+    taskKey[Unit]("run Migration Manager to detect binary incompatibilities")
+
+  lazy val settings =
+    Seq(
+      mima := {
+        val log = streams.value.log
+        mimaReferenceVersion.value.fold {
+          log.info(s"No reference version defined - skipping binary compatibility checks")
+        } { refVersion =>
+          def runOnce(prev: java.io.File, curr: java.io.File, isForward: Boolean): Unit = {
+            val direction = if (isForward) "forward" else "backward"
+            log.info(s"Checking $direction binary compatibility")
+            log.debug(s"prev = $prev, curr = $curr")
+            runMima(
+              prev = if (isForward) curr else prev,
+              curr = if (isForward) prev else curr,
+              // TODO: it would be nicer if each subproject had its own whitelist, but for now
+              // for compatibility with how Ant did things, there's just one at the root.
+              // once Ant is gone we'd be free to split it up.
+              filter = (baseDirectory in ThisBuild).value / s"bincompat-$direction.whitelist.conf",
+              log)
+          }
+          val artifact =
+            getPreviousArtifact(
+              "org.scala-lang" % s"${name.value}" % refVersion,
+              ivySbt.value, streams.value)
+          for (isForward <- Seq(false, true))
+            runOnce(artifact, (packageBin in Compile).value, isForward)
+        }
+      }
+    )
+
+  def runMima(prev: java.io.File, curr: java.io.File, filter: java.io.File, log: Logger): Unit = {
+    val args = Array(
+      "--prev", prev.getAbsolutePath,
+      "--curr", curr.getAbsolutePath,
+      "--filters", filter.getAbsolutePath,
+      "--generate-filters"
+    )
+    val exitCode = TrapExit(com.typesafe.tools.mima.cli.Main.main(args), log)
+    if (exitCode != 0)
+      throw new RuntimeException(s"MiMa failed with exit code $exitCode")
+  }
+
+  // cribbed from https://github.com/typesafehub/migration-manager/blob/master/sbtplugin/src/main/scala/com/typesafe/tools/mima/plugin/SbtMima.scala
+  def getPreviousArtifact(m: ModuleID, ivy: IvySbt, s: TaskStreams): File = {
+    val moduleSettings = InlineConfiguration(
+      "dummy" % "test" % "version",
+      ModuleInfo("dummy-test-project-for-resolving"),
+      dependencies = Seq(m))
+    val module = new ivy.Module(moduleSettings)
+    val report = Deprecated.Inner.ivyUpdate(ivy)(module, s)
+    val optFile = (for {
+      config <- report.configurations
+      module <- config.modules
+      (artifact, file) <- module.artifacts
+      // TODO - Hardcode this?
+      if artifact.name == m.name
+    } yield file).headOption
+    optFile getOrElse sys.error("Could not resolve previous artifact: " + m)
+  }
+
+}
+
+// use the SI-7934 workaround to silence a deprecation warning on an sbt API
+// we have no choice but to call.  on the lack of any suitable alternative,
+// see https://gitter.im/sbt/sbt-dev?at=5616e2681b0e279854bd74a4 :
+// "it's my intention to eventually come up with a public API" says Eugene Y
+object Deprecated {
+  @deprecated("", "") class Inner {
+    def ivyUpdate(ivy: IvySbt)(module: ivy.Module, s: TaskStreams) =
+      IvyActions.update(
+        module,
+        new UpdateConfiguration(
+          retrieve = None,
+          missingOk = false,
+          logging = UpdateLogging.DownloadOnly),
+        s.log)
+  }
+  object Inner extends Inner
+}