Better handling of repositories in updateSbtClassifiers task

plugin/src/main/scala/coursier/CoursierPlugin.scala

@@ -18,6 +18,7 @@ object CoursierPlugin extends AutoPlugin {
     val coursierCachePolicy = Keys.coursierCachePolicy
     val coursierVerbosity = Keys.coursierVerbosity
     val coursierResolvers = Keys.coursierResolvers
+    val coursierSbtResolvers = Keys.coursierSbtResolvers
     val coursierCache = Keys.coursierCache
     val coursierProject = Keys.coursierProject
     val coursierProjects = Keys.coursierProjects
@@ -34,6 +35,7 @@ object CoursierPlugin extends AutoPlugin {
     coursierCachePolicy := CachePolicy.FetchMissing,
     coursierVerbosity := 1,
     coursierResolvers <<= Tasks.coursierResolversTask,
+    coursierSbtResolvers <<= externalResolvers in updateSbtClassifiers,
     coursierCache := new File(sys.props("user.home") + "/.coursier/sbt"),
     update <<= Tasks.updateTask(withClassifiers = false),
     updateClassifiers <<= Tasks.updateTask(withClassifiers = true),

plugin/src/main/scala/coursier/Keys.scala

@@ -12,6 +12,7 @@ object Keys {
   val coursierVerbosity = SettingKey[Int]("coursier-verbosity", "")
 
   val coursierResolvers = TaskKey[Seq[Resolver]]("coursier-resolvers", "")
+  val coursierSbtResolvers = TaskKey[Seq[Resolver]]("coursier-sbt-resolvers", "")
 
   val coursierCache = SettingKey[File]("coursier-cache", "")
 

plugin/src/main/scala/coursier/Tasks.scala

@@ -123,7 +123,11 @@ object Tasks {
       val cachePolicy = coursierCachePolicy.value
       val cacheDir = coursierCache.value
 
-      val resolvers = coursierResolvers.value
+      val resolvers =
+        if (sbtClassifiers)
+          coursierSbtResolvers.value
+        else
+          coursierResolvers.value
 
       val verbosity = coursierVerbosity.value