Fix creating static forwarders for inherited methods

We should create static forwarders for the methods inherited
on the companion object, not on the class itself.

Author: raboof

plugin/src/main/scala/com/typesafe/genjavadoc/BasicTransform.scala

@@ -17,7 +17,7 @@ trait BasicTransform { this: TransformCake ⇒
 
   def newTransformUnit(unit: CompilationUnit): Unit = {
     superTransformUnit(unit)
-    for (c ← flatten(classes.flatMap(liftInterface))) {
+    for (c ← flattenObjects(classes.flatMap(liftInterface))) {
       val out = file(c.file)
       try {
         if (c.pckg != "<empty>") out.println(s"package ${c.pckg};")

plugin/src/main/scala/com/typesafe/genjavadoc/Output.scala

@@ -88,7 +88,7 @@ trait Output { this: TransformCake ⇒
    *
    * The first two parts are to be applied recursively to nested objects.
    */
-  def flatten(c: Vector[ClassInfo], forwarders: Boolean = true, staticScope: Boolean = true): Vector[ClassInfo] = {
+  def flattenObjects(c: Vector[ClassInfo], forwarders: Boolean = true, staticScope: Boolean = true): Vector[ClassInfo] = {
     val (obj: Vector[ClassInfo], cls: Vector[ClassInfo]) = c collect PreFilter partition (_.module)
     val classes = cls.map(c ⇒ c.name -> c).toMap
     val objects = obj.map(o ⇒ o.name -> o).toMap
@@ -99,7 +99,7 @@ trait Output { this: TransformCake ⇒
         case (Some(o), Some(c))            ⇒ merge(o, c, forwarders, staticScope)
         case (Some(o), None) if forwarders ⇒ merge(o, fabricateCompanion(o), forwarders, staticScope)
         case (Some(o), None)               ⇒ Vector(mangleModule(o, addMODULE = forwarders, pruneClasses = false))
-        case (None, Some(c))               ⇒ Vector(c.copy(members = flatten(c.classMembers) ++ c.methodMembers.sortBy(_.name)))
+        case (None, Some(c))               ⇒ Vector(c.copy(members = flattenObjects(c.classMembers) ++ c.methodMembers.sortBy(_.name)))
         case (None, None)                  ⇒ ???
       }
     }
@@ -131,7 +131,7 @@ trait Output { this: TransformCake ⇒
 
     val members = moduleInstance ++: (
       if (pruneClasses) obj.methodMembers
-      else flatten(obj.classMembers) ++ obj.methodMembers
+      else flattenObjects(obj.classMembers) ++ obj.methodMembers
       )
 
     val (com: Seq[String], moduleMembers: Vector[Templ]) = members.foldLeft((obj.comment, Vector.empty[Templ]))((p, mem) ⇒ mem match {
@@ -163,11 +163,11 @@ trait Output { this: TransformCake ⇒
           case m: MethodInfo if !(m.name == obj.name) && !cls.members.exists(_.name == m.name) ⇒
             m.copy(pattern = n ⇒ "static " + m.pattern(n))
         }
-        val exclude = (direct.iterator ++ methods.iterator).map(_.name).toSet ++ this.javaKeywords
-        direct ++ inheritedMethods(cls.sym, exclude)
+        val exclude = (direct.iterator ++ methods.iterator).map(_.name).toSet ++ this.javaKeywords ++ excludedForwarders
+        direct ++ inheritedMethods(obj.sym, exclude)
       }
-    val nestedClasses = flatten(classes, forwarders = false, staticScope = false)
-    val nestedStaticClasses = flatten(staticClasses, forwarders = false, staticScope = staticScope)
+    val nestedClasses = flattenObjects(classes, forwarders = false, staticScope = false)
+    val nestedStaticClasses = flattenObjects(staticClasses, forwarders = false, staticScope = staticScope)
     if (forwarders) {
       val base = cls.copy(members = nestedClasses ++ nestedStaticClasses ++ staticMethods ++ methods)
       val mod = mangleModule(obj, addMODULE = forwarders, pruneClasses = true)
@@ -179,6 +179,13 @@ trait Output { this: TransformCake ⇒
     }
   }
 
+  private val excludedForwarders =
+    // For case classes, there is a generated companion object that
+    // implements `AbstractFunctionN`, but static forwarders are not created
+    // on the class for the methods on the companion object inherited from
+    // that:
+    Seq("curried", "tupled")
+
   private def inheritedMethods(sym: global.Symbol, exclude: Set[String]): Seq[MethodInfo] = {
     import global._
     sym.ancestors.reverse

plugin/src/test/resources/expected_output/basic/akka/actor/typed/DispatcherSelector.java

@@ -1,14 +1,5 @@
 package akka.actor.typed;
 public abstract class DispatcherSelector extends akka.actor.typed.Props {
   static private  java.lang.Object readResolve ()  { throw new RuntimeException(); }
-  static public abstract  boolean canEqual (Object that)  ;
-  static public abstract  boolean equals (Object that)  ;
-  static public abstract  Object productElement (int n)  ;
-  static public abstract  int productArity ()  ;
-  static public  scala.collection.Iterator<java.lang.Object> productIterator ()  { throw new RuntimeException(); }
-  static public  java.lang.String productPrefix ()  { throw new RuntimeException(); }
-  static public  java.lang.String productElementName (int n)  { throw new RuntimeException(); }
-  static public  scala.collection.Iterator<java.lang.String> productElementNames ()  { throw new RuntimeException(); }
-  static public abstract  akka.actor.typed.Props next ()  ;
   public   DispatcherSelector ()  { throw new RuntimeException(); }
 }

plugin/src/test/resources/patches/2.13.0.patch

@@ -155,14 +155,6 @@ index b0dd497..4950950 100644
    }
 --- target/expected_output/basic/akka/rk/buh/is/it/CompressionProtocol.java
 +++ target/expected_output/basic/akka/rk/buh/is/it/CompressionProtocol.java
-@@ -9,6 +9,7 @@
-       static public  akka.rk.buh.is.it.CompressionProtocol.Events.HeavyHitterDetected apply (Object key, int id, long count)  { throw new RuntimeException(); }
-       static public  scala.Option<scala.Tuple3<java.lang.Object, java.lang.Object, java.lang.Object>> unapply (akka.rk.buh.is.it.CompressionProtocol.Events.HeavyHitterDetected x$0)  { throw new RuntimeException(); }
-       static private  java.lang.Object readResolve ()  { throw new RuntimeException(); }
-+      static public  scala.collection.Iterator<java.lang.String> productElementNames ()  { throw new RuntimeException(); }
-       public  Object key ()  { throw new RuntimeException(); }
-       public  int id ()  { throw new RuntimeException(); }
-       public  long count ()  { throw new RuntimeException(); }
 @@ -23,6 +24,7 @@
        public  java.lang.String productPrefix ()  { throw new RuntimeException(); }
        public  int productArity ()  { throw new RuntimeException(); }
@@ -173,14 +165,6 @@ index b0dd497..4950950 100644
        public  int hashCode ()  { throw new RuntimeException(); }
 --- target/expected_output/basic/akka/rk/buh/is/it/EWMA.java
 +++ target/expected_output/basic/akka/rk/buh/is/it/EWMA.java
-@@ -28,6 +28,7 @@
-   static public  akka.rk.buh.is.it.EWMA apply (double value, double alpha) { throw new RuntimeException(); }
-   static public  scala.Option<scala.Tuple2<java.lang.Object, java.lang.Object>> unapply (akka.rk.buh.is.it.EWMA x$0) { throw new RuntimeException(); }
-   static private  java.lang.Object readResolve () { throw new RuntimeException(); }
-+  static public  scala.collection.Iterator<java.lang.String> productElementNames ()  { throw new RuntimeException(); }
-   public  double value () { throw new RuntimeException(); }
-   public  double alpha () { throw new RuntimeException(); }
-   // not preceding
 @@ -48,6 +49,7 @@
    public  java.lang.String productPrefix () { throw new RuntimeException(); }
    public  int productArity () { throw new RuntimeException(); }