Use correct validator when creating an enum codec so that error messa…

…ges are rendered correctly (#4175)

core/src/main/scala/sttp/tapir/macros/CreateDerivedEnumerationCodec.scala

@@ -30,7 +30,7 @@ class CreateDerivedEnumerationCodec[L, T](validator: Validator.Enumeration[T], s
       .mapDecode(s =>
         decode(s) match {
           case Some(value) => DecodeResult.Value(value)
-          case None        => DecodeResult.InvalidValue(List(ValidationError(validator, s)))
+          case None        => DecodeResult.InvalidValue(List(ValidationError(v, s)))
         }
       )(encode)
       .schema(schemaAnnotations.enrich(s))

examples/src/main/scala/sttp/tapir/examples/custom_types/enumQueryParameter.scala

@@ -0,0 +1,27 @@
+// {cat=Custom types; effects=Direct; server=Netty}: A query parameter which maps to a Scala 3 enum (enumeration)
+
+//> using dep com.softwaremill.sttp.tapir::tapir-core:1.11.9
+//> using dep com.softwaremill.sttp.tapir::tapir-netty-server-sync:1.11.9
+//> using dep ch.qos.logback:logback-classic:1.5.8
+
+package sttp.tapir.examples.custom_types
+
+import sttp.tapir.*
+import sttp.tapir.server.netty.sync.NettySyncServer
+
+enum PieType(val index: Int, val name: String):
+  case Apple extends PieType(1, "apple")
+  case Orange extends PieType(2, "orange")
+  case BananaCustard extends PieType(3, "banana-custard")
+
+@main def enumQueryParameter(): Unit =
+  given Codec[String, PieType, CodecFormat.TextPlain] =
+    Codec.derivedEnumeration[String, PieType](decode = s => PieType.values.find(_.name == s), encode = _.name)
+
+  val bake = endpoint.get
+    .in("bake")
+    .in(query[PieType]("pie"))
+    .out(stringBody)
+    .handleSuccess(pie => s"Baking: $pie!")
+
+  NettySyncServer().addEndpoint(bake).startAndWait()