Fixed the default values macro to use constructor instead of apply

Fixes #1

core/src/main/scala/io/github/netvl/picopickle/defaults.scala

@@ -36,20 +36,19 @@ trait DefaultValueMacros extends ContextExtensions with SingletonTypeMacrosExten
 
     val tTpe = weakTypeOf[T]
     val tCompanionSym = companion(tTpe.typeSymbol)
-
     if (tCompanionSym == NoSymbol)
       c.abort(c.enclosingPosition, s"No companion symbol is available for type $tTpe")
 
-    val applySym = decl(tCompanionSym.typeSignature, termName("apply")).asMethod
-    if (applySym == NoSymbol)
-      c.abort(c.enclosingPosition, s"Companion symbol for type $tTpe does not have apply method")
+    val ctorSym = decl(tTpe, names.CONSTRUCTOR).asTerm.alternatives.collectFirst {
+      case ctor: MethodSymbol if ctor.isPrimaryConstructor => ctor
+    }.getOrElse(c.abort(c.enclosingPosition, s"Could not find the primary constructor for type $tTpe"))
 
     val vTpe = weakTypeOf[V]
 
-    val defaultMethodName = paramLists(applySym).headOption.flatMap { argSyms =>
+    val defaultMethodName = paramLists(ctorSym).headOption.flatMap { argSyms =>
       argSyms.map(_.asTerm).zipWithIndex.collect {
         case (p, i) if p.isParamWithDefault && p.name.toString == fieldName && p.typeSignature =:= vTpe =>
-          termName(s"apply$$default$$${i+1}")
+          termName(s"$$lessinit$$greater$$default$$${i+1}")  // TODO: not sure if this couldn't be made more correct
       }.headOption
     }
 

core/src/test/scala/io/github/netvl/picopickle/Fixtures.scala

@@ -33,4 +33,18 @@ object Fixtures {
     sealed trait Root
     case class A(x: Int, name: String = "me", enabled: Boolean = false) extends Root
   }
+
+  object WithOverloadedApplyMethod {
+    case class A(x: Int, y: String, z: Double = 12.3)
+
+    object A {
+      def apply(s: String): A = A(s.toInt, s, s.toDouble)
+    }
+  }
+
+  object WithOverloadedConstructor {
+    case class A(x: Int, y: String, z: Double = 12.3) {
+      def this(s: String) = this(s.toInt, s, s.toDouble)
+    }
+  }
 }

project/tests/Pickler.yml

@@ -250,4 +250,18 @@ cases:
       - - 'A(10, null)'
         - 'Map("x" -> 10, "y" -> null)'
         - '"""{"x":10,"y":null}"""'
+  - name: case classes with an overloaded apply method in their companions
+    prepend: |
+      import WithOverloadedApplyMethod._
+    rw:
+      - - 'A(1, "2", 3.4)'
+        - 'Map("x" -> 1, "y" -> "2", "z" -> 3.4)'
+        - '"""{"x":1,"y":"2","z":3.4}"""'
+  - name: case classes with an overloaded constructor
+    prepend: |
+      import WithOverloadedConstructor._
+    rw:
+      - - 'A(1, "2", 3.4)'
+        - 'Map("x" -> 1, "y" -> "2", "z" -> 3.4)'
+        - '"""{"x":1,"y":"2","z":3.4}"""'