Fix sneaky binary incompatibility in Discover.scala

main/define/src/mill/define/Discover.scala

@@ -16,15 +16,24 @@ import scala.reflect.macros.blackbox
  * the `T.command` methods we find. This mapping from `Class[_]` to `MainData`
  * can then be used later to look up the `MainData` for any module.
  */
-case class Discover[T] private (val value: Map[
-  Class[_],
-  (Seq[String], Seq[mainargs.MainData[_, _]])
-])
+case class Discover[T] private (
+    val value: Map[
+      Class[_],
+      (Seq[String], Seq[mainargs.MainData[_, _]])
+    ],
+    dummy: Int = 0 /* avoid conflict with Discover.apply(value: Map) below*/
+) {
+  def this(value: Map[Class[_], Seq[mainargs.MainData[_, _]]]) =
+    this(value.mapValues((Nil, _)).toMap)
+}
 
 object Discover {
   def apply2[T](value: Map[Class[_], (Seq[String], Seq[mainargs.MainData[_, _]])]): Discover[T] =
     new Discover[T](value)
 
+  def apply[T](value: Map[Class[_], Seq[mainargs.MainData[_, _]]]): Discover[T] =
+    new Discover[T](value.mapValues((Nil, _)).toMap)
+
   def apply[T]: Discover[T] = macro Router.applyImpl[T]
 
   private class Router(val ctx: blackbox.Context) extends mainargs.Macros(ctx) {

main/resolve/src/mill/resolve/Resolve.scala

@@ -227,11 +227,11 @@ trait Resolve[T] {
       nullCommandDefaults: Boolean
   ): Either[String, Seq[T]] = {
     val rootResolved = ResolveCore.Resolved.Module(Segments(), rootModule.getClass)
-    val allPossibleNames = rootModule.millDiscover.value.values.flatMap(_._1).toSet
     val resolved =
       ResolveCore.resolve(rootModule, sel.value.toList, rootResolved, Segments()) match {
         case ResolveCore.Success(value) => Right(value)
         case ResolveCore.NotFound(segments, found, next, possibleNexts) =>
+          val allPossibleNames = rootModule.millDiscover.value.values.flatMap(_._1).toSet
           Left(ResolveNotFoundHandler(sel, segments, found, next, possibleNexts, allPossibleNames))
         case ResolveCore.Error(value) => Left(value)
       }