Scala3 support for non discriminator play json union (#702)

apicollective · Jul 3, 2024 · c383db9 · c383db9
1 parent 3ebda99
commit c383db9
Showing 1 changed file with 28 additions and 1 deletion.
diff --git a/scala-generator/src/main/scala/models/Play2Json.scala b/scala-generator/src/main/scala/models/Play2Json.scala
@@ -232,6 +232,34 @@ case class Play2Json(
   }
 
   private def readersWithoutDiscriminator(union: ScalaUnion): String = {
+    if (scala3Support) {
+      readersWithoutDiscriminatorScala3(union)
+    } else {
+      readersWithoutDiscriminatorScala2(union)
+    }
+  }
+
+  private def readersWithoutDiscriminatorScala3(union: ScalaUnion): String = {
+    union.types.toList match {
+      case Nil => {
+        s"${play2JsonCommon.implicitUnionReader(union)} = (json: play.api.libs.json.JsValue) => play.api.libs.json.JsError(\"Union has no declared types\")"
+      }
+      case first :: rest => {
+        val types = (Seq("default") ++ rest.map { scalaUnionType =>
+          s"${readerUnqualified(union, scalaUnionType)}.reads(json).map(_.asInstanceOf[T])"
+        }).mkString("Seq(\n    ", ",\n    ", "\n  )")
+        s"""
+           |${play2JsonCommon.implicitUnionReader(union)} = (json: play.api.libs.json.JsValue) => {
+           |  val default = ${readerUnqualified(union, first)}.reads(json).map(_.asInstanceOf[T])
+           |  val all: Seq[play.api.libs.json.JsResult[T]] = $types
+           |  all.view.find(_.isSuccess).getOrElse(default)
+           |}
+           |""".stripMargin
+      }
+    }
+  }
+
+  private def readersWithoutDiscriminatorScala2(union: ScalaUnion): String = {
     Seq(
       s"${play2JsonCommon.implicitUnionReader(union)} = {",
       s"  (",
@@ -263,7 +291,6 @@ case class Play2Json(
         Seq(
           "discriminator match {",
           unionTypesWithNames(union).map { t =>
-            // OLD: Pre scala3: s"""case "${t.unionType.discriminatorName}" => js.validate[${t.typeName}]"""
             s"""case "${t.unionType.discriminatorName}" => ${play2JsonCommon.implicitReaderNameQualified(ssd.namespaces, t.unionType.name)}.reads(js)"""
           }.mkString("\n").indentString(2),
           s"""case other => play.api.libs.json.JsSuccess(${union.undefinedType.datatype.fullName}(other))""".indentString(2),