Add new `csrSameVersions` setting, use it for Scala artifacts

The `csrSameVersions` setting can be used to keep dependencies at the
same version.

By default it's used for Scala artifacts. They need to be kept at the
same version because the compiler / reflect are built with
cross-artifact inlining enabled.

`csrSameVersions := Seq(Set(scala-library, scala-reflect, scala-compiler, scalap))`

Users can make use of the new setting in the following way:
  - `csrSameVersions += Set[InclExclRule]("com.corp" % "lib", "com.corp" % "lub")`
  - `csrSameVersions += Set[InclExclRule]("com.corp" % "lib-family-*")`

main/src/main/scala/sbt/Defaults.scala

@@ -271,6 +271,9 @@ object Defaults extends BuildCommon {
       csrLogger := LMCoursier.coursierLoggerTask.value,
       csrMavenProfiles :== Set.empty,
       csrReconciliations :== LMCoursier.relaxedForAllModules,
+      csrSameVersions := Seq(
+        ScalaArtifacts.Artifacts.map(a => InclExclRule(scalaOrganization.value, a)).toSet
+      )
     )
 
   /** Core non-plugin settings for sbt builds.  These *must* be on every build or the sbt engine will fail to run at all. */

main/src/main/scala/sbt/Keys.scala

@@ -452,6 +452,7 @@ object Keys {
   val csrExtraCredentials = taskKey[Seq[lmcoursier.credentials.Credentials]]("")
   val csrPublications = taskKey[Seq[(lmcoursier.definitions.Configuration, lmcoursier.definitions.Publication)]]("")
   val csrReconciliations = settingKey[Seq[(ModuleMatchers, Reconciliation)]]("Strategy to reconcile version conflicts.")
+  val csrSameVersions = settingKey[Seq[Set[InclExclRule]]]("Modules to keep at the same version.")
 
   val internalConfigurationMap = settingKey[Configuration => Configuration]("Maps configurations to the actual configuration used to define the classpath.").withRank(CSetting)
   val classpathConfiguration = taskKey[Configuration]("The configuration used to define the classpath.").withRank(CTask)

main/src/main/scala/sbt/coursierint/LMCoursier.scala

@@ -74,6 +74,7 @@ object LMCoursier {
   def relaxedForAllModules: Seq[(ModuleMatchers, Reconciliation)] =
     Vector((ModuleMatchers.all, Reconciliation.Relaxed))
 
+  // For binary compatibility / MiMa
   def coursierConfiguration(
       rs: Seq[Resolver],
       interProjectDependencies: Seq[CProject],
@@ -119,6 +120,58 @@ object LMCoursier {
       strict,
       depsOverrides,
       None,
+      Nil,
+      log
+    )
+
+  // For binary compatibility / MiMa
+  def coursierConfiguration(
+      rs: Seq[Resolver],
+      interProjectDependencies: Seq[CProject],
+      extraProjects: Seq[CProject],
+      fallbackDeps: Seq[FallbackDependency],
+      appConfig: AppConfiguration,
+      classifiers: Option[Seq[Classifier]],
+      profiles: Set[String],
+      scalaOrg: String,
+      scalaVer: String,
+      scalaBinaryVer: String,
+      autoScalaLib: Boolean,
+      scalaModInfo: Option[ScalaModuleInfo],
+      excludeDeps: Seq[InclExclRule],
+      credentials: Seq[Credentials],
+      createLogger: Option[CacheLogger],
+      cacheDirectory: File,
+      reconciliation: Seq[(ModuleMatchers, Reconciliation)],
+      ivyHome: Option[File],
+      strict: Option[CStrict],
+      depsOverrides: Seq[ModuleID],
+      updateConfig: Option[UpdateConfiguration],
+      log: Logger
+  ): CoursierConfiguration =
+    coursierConfiguration(
+      rs,
+      interProjectDependencies,
+      extraProjects,
+      fallbackDeps,
+      appConfig,
+      classifiers,
+      profiles,
+      scalaOrg,
+      scalaVer,
+      scalaBinaryVer,
+      autoScalaLib,
+      scalaModInfo,
+      excludeDeps,
+      credentials,
+      createLogger,
+      cacheDirectory,
+      reconciliation,
+      ivyHome,
+      strict,
+      depsOverrides,
+      updateConfig,
+      Nil,
       log
     )
 
@@ -144,6 +197,7 @@ object LMCoursier {
       strict: Option[CStrict],
       depsOverrides: Seq[ModuleID],
       updateConfig: Option[UpdateConfiguration],
+      sameVersions: Seq[Set[InclExclRule]],
       log: Logger
   ): CoursierConfiguration = {
     val coursierExcludeDeps = Inputs
@@ -197,6 +251,7 @@ object LMCoursier {
       .withStrict(strict)
       .withForceVersions(userForceVersions.toVector)
       .withMissingOk(missingOk)
+      .withSameVersions(sameVersions)
   }
 
   def coursierConfigurationTask: Def.Initialize[Task[CoursierConfiguration]] = Def.task {
@@ -223,6 +278,7 @@ object LMCoursier {
       CoursierInputsTasks.strictTask.value,
       dependencyOverrides.value,
       Some(updateConfiguration.value),
+      csrSameVersions.value,
       streams.value.log
     )
   }
@@ -251,6 +307,7 @@ object LMCoursier {
       CoursierInputsTasks.strictTask.value,
       dependencyOverrides.value,
       Some(updateConfiguration.value),
+      csrSameVersions.value,
       streams.value.log
     )
   }
@@ -279,6 +336,7 @@ object LMCoursier {
       CoursierInputsTasks.strictTask.value,
       dependencyOverrides.value,
       Some(updateConfiguration.value),
+      csrSameVersions.value,
       streams.value.log
     )
   }
@@ -307,6 +365,7 @@ object LMCoursier {
       CoursierInputsTasks.strictTask.value,
       dependencyOverrides.value,
       Some(updateConfiguration.value),
+      csrSameVersions.value,
       streams.value.log
     )
   }