.

Author: lihaoyi

runner/meta/src/mill/meta/CodeGen.scala

@@ -307,6 +307,10 @@ object CodeGen {
     val expectedModuleMsg =
       if (projectRoot != millTopLevelProjectRoot) "MillBuildRootModule" else "mill.Module"
 
+    val newParent =
+      if (segments.isEmpty) "_root_.mill.util.MainRootModule"
+      else "_root_.mill.api.internal.SubfolderModule(build.millDiscover)"
+
     val headerCode =
       s"""|$generatedFileHeader
           |package $pkg
@@ -315,16 +319,13 @@ object CodeGen {
           |$importSiblingScripts
           |$prelude
           |
-          |object ${CGConst.wrapperObjectName} extends ${CGConst.wrapperObjectName} {
+          |object ${CGConst.wrapperObjectName} extends $newParent with ${CGConst.wrapperObjectName} {
           |  ${childAliases.linesWithSeparators.mkString("  ")}
           |  ${exportSiblingScripts.linesWithSeparators.mkString("  ")}
           |  ${millDiscover(segments.nonEmpty)}
           |}
           |""".stripMargin
 
-    val newParent =
-      if (segments.isEmpty) "_root_.mill.util.MainRootModule"
-      else "_root_.mill.api.internal.SubfolderModule(build.millDiscover)"
 
     objectData.find(o => o.name.text == "`package`") match {
       case Some(objectData) =>
@@ -347,29 +348,6 @@ object CodeGen {
           case None => ()
         }
 
-        newScriptCode = objectData.parent.applyTo(
-          newScriptCode,
-          if (objectData.parent.text == null) {
-            throw new Result.Exception(
-              s"object `package` in ${scriptPath.relativeTo(millTopLevelProjectRoot)} " +
-                s"must extend a subclass of `$expectedModuleMsg`"
-            )
-          } else {
-            // `extends` clauses can have the parent followed by either `with` or `,`
-            // separators, but it needs to be consistent. So we need to try and see if
-            // any separators are already present and if so follow suite. Not 100%
-            // precise, but probably works well enough people will rarely hit issues
-            val postParent = newScriptCode.drop(objectData.parent.end).trim
-            val sep = {
-              if (postParent.startsWith(",")) ", "
-              else if (postParent.startsWith("with")) " with "
-              else ", " // no separator found, just use `,` by default
-            }
-
-            newParent + sep + objectData.parent.text
-          }
-        )
-
         newScriptCode = objectData.name.applyTo(newScriptCode, CGConst.wrapperObjectName)
         newScriptCode = objectData.obj.applyTo(newScriptCode, "trait")
 
@@ -380,8 +358,7 @@ object CodeGen {
 
       case None =>
         s"""$headerCode
-           |trait ${CGConst.wrapperObjectName}
-           |    extends $newParent { this: ${CGConst.wrapperObjectName}.type =>
+           |trait ${CGConst.wrapperObjectName} extends mill.Module{ this: ${CGConst.wrapperObjectName}.type =>
            |$markerComment
            |$scriptCode
            |}""".stripMargin