FDN-4338: remove unused upsertedDiscriminator field

src/main/scala/io/flow/stream/Controller.scala

@@ -363,27 +363,11 @@ case class Controller() extends io.flow.build.Controller {
     }
   }
 
-  // Custom Writes for CapturedType to output both upsertedDiscriminator (for backward compatibility)
-  // and upsertedDiscriminators (new format). Can remove upsertedDiscriminator once all clients updated.
-  private[stream] implicit val capturedTypeWrites: play.api.libs.json.Writes[CapturedType] = {
-    import play.api.libs.json._
-    import io.apibuilder.spec.v0.models.json._
-    (ct: CapturedType) =>
-      Json.obj(
-        "fieldName" -> ct.fieldName,
-        "typeName" -> ct.typeName,
-        "modelType" -> ct.modelType,
-        "upsertedDiscriminator" -> ct.upsertedDiscriminators.headOption.getOrElse[String](""),
-        "deletedDiscriminator" -> ct.deletedDiscriminator,
-        "deletedHasModel" -> ct.deletedHasModel,
-        "upsertedDiscriminators" -> ct.upsertedDiscriminators,
-      )
-  }
-
   def saveDescriptor(buildType: BuildType, output: Path, descriptor: StreamDescriptor): Unit = {
     import play.api.libs.json._
     import io.apibuilder.spec.v0.models.json._
 
+    implicit val w1: Writes[CapturedType] = Json.writes[CapturedType]
     implicit val w2: Writes[KinesisStream] = Json.writes[KinesisStream]
     implicit val w3: Writes[StreamDescriptor] = Json.writes[StreamDescriptor]
     val path = output.resolve(s"flow-$buildType-streams.json").toFile

src/test/scala/io/flow/stream/ControllerSpec.scala

@@ -3,7 +3,6 @@ package io.flow.stream
 import io.apibuilder.spec.v0.models.{Field, Model}
 import org.scalatest.funspec.AnyFunSpec
 import org.scalatest.matchers.should.Matchers
-import play.api.libs.json.Json
 
 class ControllerSpec extends AnyFunSpec with Matchers {
 
@@ -19,49 +18,6 @@ class ControllerSpec extends AnyFunSpec with Matchers {
     Field(name = name, `type` = "string", required = true)
   }
 
-  describe("CapturedType JSON serialization") {
-    val controller = Controller()
-    import controller.capturedTypeWrites
-
-    it("serializes with single upsertedDiscriminator for backward compatibility") {
-      val capturedType = CapturedType(
-        fieldName = "order",
-        typeName = "order",
-        modelType = makeModel("order", Seq(makeIdField())),
-        upsertedDiscriminators = Seq("order_upserted"),
-        deletedDiscriminator = "order_deleted",
-        deletedHasModel = true,
-      )
-
-      val json = Json.toJson(capturedType)
-
-      (json \ "upsertedDiscriminator").as[String] shouldBe "order_upserted"
-      (json \ "upsertedDiscriminators").as[Seq[String]] shouldBe Seq("order_upserted")
-      (json \ "fieldName").as[String] shouldBe "order"
-      (json \ "typeName").as[String] shouldBe "order"
-      (json \ "deletedDiscriminator").as[String] shouldBe "order_deleted"
-      (json \ "deletedHasModel").as[Boolean] shouldBe true
-    }
-
-    it("serializes multiple upsertedDiscriminators (inserted + updated)") {
-      val capturedType = CapturedType(
-        fieldName = "item",
-        typeName = "item",
-        modelType = makeModel("item", Seq(makeIdField())),
-        upsertedDiscriminators = Seq("item_inserted", "item_updated"),
-        deletedDiscriminator = "item_deleted",
-        deletedHasModel = false,
-      )
-
-      val json = Json.toJson(capturedType)
-
-      // Backward compatibility: first discriminator is used
-      (json \ "upsertedDiscriminator").as[String] shouldBe "item_inserted"
-      // New format: all discriminators included
-      (json \ "upsertedDiscriminators").as[Seq[String]] shouldBe Seq("item_inserted", "item_updated")
-    }
-  }
-
   describe("UnionMemberRx pattern matching") {
     val controller = Controller()
     import controller.UnionMemberRx