Codegen any type support

openapi-codegen/core/src/main/scala/sttp/tapir/codegen/BasicGenerator.scala

@@ -2,6 +2,7 @@ package sttp.tapir.codegen
 
 import sttp.tapir.codegen.openapi.models.OpenapiModels.OpenapiDocument
 import sttp.tapir.codegen.openapi.models.OpenapiSchemaType.{
+  OpenapiSchemaAny,
   OpenapiSchemaBoolean,
   OpenapiSchemaDouble,
   OpenapiSchemaEnum,
@@ -66,6 +67,8 @@ object BasicGenerator {
         ("String", nb)
       case OpenapiSchemaBoolean(nb) =>
         ("Boolean", nb)
+      case OpenapiSchemaAny(nb) =>
+        ("io.circe.Json", nb)
       case OpenapiSchemaRef(t) =>
         (t.split('/').last, false)
       case x => throw new NotImplementedError(s"Not all simple types supported! Found $x")

openapi-codegen/core/src/main/scala/sttp/tapir/codegen/openapi/models/OpenapiSchemaType.scala

@@ -83,6 +83,10 @@ object OpenapiSchemaType {
     val nullable = false
   }
 
+  case class OpenapiSchemaAny(
+      nullable: Boolean
+  ) extends OpenapiSchemaSimpleType
+
   case class OpenapiSchemaConstantString(
       value: String
   ) extends OpenapiSchemaType {
@@ -251,10 +255,7 @@ object OpenapiSchemaType {
 
   implicit val OpenapiSchemaObjectDecoder: Decoder[OpenapiSchemaObject] = { (c: HCursor) =>
     for {
-      _ <- c
-        .downField("type")
-        .as[Option[String]]
-        .ensure(DecodingFailure("Given type is not object!", c.history))(v => v.forall(_ == "object"))
+      _ <- c.downField("type").as[String].ensure(DecodingFailure("Given type is not object!", c.history))(v => v == "object")
       f <- c.downField("properties").as[Option[Map[String, OpenapiSchemaType]]]
       r <- c.downField("required").as[Option[Seq[String]]]
       nb <- c.downField("nullable").as[Option[Boolean]]
@@ -283,6 +284,15 @@ object OpenapiSchemaType {
     }
   }
 
+  implicit val OpenapiSchemaAnyDecoder: Decoder[OpenapiSchemaAny] = { (c: HCursor) =>
+    for {
+      _ <- c.downField("type").as[Option[String]].ensure(DecodingFailure("Type must not be defined!", c.history))(_.isEmpty)
+      nb <- c.downField("nullable").as[Option[Boolean]]
+    } yield {
+      OpenapiSchemaAny(nb.getOrElse(false))
+    }
+  }
+
   implicit lazy val OpenapiSchemaTypeDecoder: Decoder[OpenapiSchemaType] =
     List[Decoder[OpenapiSchemaType]](
       Decoder[OpenapiSchemaEnum].widen,
@@ -291,6 +301,7 @@ object OpenapiSchemaType {
       Decoder[OpenapiSchemaNot].widen,
       Decoder[OpenapiSchemaMap].widen,
       Decoder[OpenapiSchemaObject].widen,
-      Decoder[OpenapiSchemaArray].widen
+      Decoder[OpenapiSchemaArray].widen,
+      Decoder[OpenapiSchemaAny].widen
     ).reduceLeft(_ or _)
 }

openapi-codegen/core/src/test/scala/sttp/tapir/codegen/ClassDefinitionGeneratorSpec.scala

@@ -3,6 +3,7 @@ package sttp.tapir.codegen
 import sttp.tapir.codegen.openapi.models.OpenapiComponent
 import sttp.tapir.codegen.openapi.models.OpenapiModels.OpenapiDocument
 import sttp.tapir.codegen.openapi.models.OpenapiSchemaType.{
+  OpenapiSchemaAny,
   OpenapiSchemaArray,
   OpenapiSchemaConstantString,
   OpenapiSchemaEnum,
@@ -108,6 +109,23 @@ class ClassDefinitionGeneratorSpec extends CompileCheckTestBase {
     new ClassDefinitionGenerator().classDefs(doc).get shouldCompile ()
   }
 
+  it should "generate class with any type" in {
+    val doc = OpenapiDocument(
+      "",
+      null,
+      null,
+      Some(
+        OpenapiComponent(
+          Map(
+            "Test" -> OpenapiSchemaObject(Map("anyType" -> OpenapiSchemaAny(false)), Seq("anyType"), false)
+          )
+        )
+      )
+    )
+
+    new ClassDefinitionGenerator().classDefs(doc).get shouldCompile ()
+  }
+
   it should "generate class with inner class" in {
     val doc = OpenapiDocument(
       "",

openapi-codegen/core/src/test/scala/sttp/tapir/codegen/models/SchemaParserSpec.scala

@@ -2,6 +2,7 @@ package sttp.tapir.codegen.openapi.models
 
 import sttp.tapir.codegen.openapi.models.OpenapiModels.OpenapiResponseContent
 import sttp.tapir.codegen.openapi.models.OpenapiSchemaType.{
+  OpenapiSchemaAny,
   OpenapiSchemaArray,
   OpenapiSchemaInt,
   OpenapiSchemaMap,
@@ -27,6 +28,7 @@ class SchemaParserSpec extends AnyFlatSpec with Matchers with Checkers {
     val yaml = """
       |schemas:
       |  User:
+      |    type: object
       |    properties:
       |      id:
       |        type: integer
@@ -61,6 +63,7 @@ class SchemaParserSpec extends AnyFlatSpec with Matchers with Checkers {
     val yaml = """
       |schemas:
       |  User:
+      |    type: object
       |    properties:
       |      attributes:
       |        type: object
@@ -87,6 +90,34 @@ class SchemaParserSpec extends AnyFlatSpec with Matchers with Checkers {
     )
   }
 
+  it should "parse any type" in {
+    val yaml = """
+      |schemas:
+      |  User:
+      |    type: object
+      |    properties:
+      |      anyValue: {}
+      |    required:
+      |      - anyValue""".stripMargin
+
+    val res = parser
+      .parse(yaml)
+      .leftMap(err => err: Error)
+      .flatMap(_.as[OpenapiComponent])
+
+    res shouldBe Right(
+      OpenapiComponent(
+        Map(
+          "User" -> OpenapiSchemaObject(
+            Map("anyValue" -> OpenapiSchemaAny(false)),
+            Seq("anyValue"),
+            false
+          )
+        )
+      )
+    )
+  }
+
   it should "parse security schemes" in {
     val yaml =
       """