From 719fb1549a0ad93edd231b17acc45e904e667946 Mon Sep 17 00:00:00 2001
From: Jules Ivanic <jules.ivanic@gmail.com>
Date: Sat, 24 Aug 2024 04:31:46 +1000
Subject: [PATCH] Fix `Map` representation in generated OpenAPI specs (#3049)

---
 .../zio/http/gen/openapi/EndpointGen.scala    | 12 +++++-----
 .../endpoint/openapi/OpenAPIGenSpec.scala     | 11 ++++++----
 .../http/endpoint/openapi/JsonSchema.scala    | 22 ++++++++++++++++++-
 3 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/zio-http-gen/src/main/scala/zio/http/gen/openapi/EndpointGen.scala b/zio-http-gen/src/main/scala/zio/http/gen/openapi/EndpointGen.scala
index 1de39e8bf6..8b760d7254 100644
--- a/zio-http-gen/src/main/scala/zio/http/gen/openapi/EndpointGen.scala
+++ b/zio-http-gen/src/main/scala/zio/http/gen/openapi/EndpointGen.scala
@@ -1007,11 +1007,9 @@ final case class EndpointGen(config: Config) {
       case JsonSchema.ArrayType(None, _, _)         => None
       case JsonSchema.ArrayType(Some(schema), _, _) =>
         schemaToCode(schema, openAPI, name, annotations)
-      case JsonSchema.Object(properties, additionalProperties, _)
-          if properties.nonEmpty && additionalProperties.isRight =>
-        // Can't be an object and a map at the same time
+      case obj: JsonSchema.Object if obj.isInvalid  =>
         throw new Exception("Object with properties and additionalProperties is not supported")
-      case obj @ JsonSchema.Object(properties, additionalProperties, _) if additionalProperties.isLeft =>
+      case obj @ JsonSchema.Object(properties, _, _) if obj.isClosedDictionary =>
         val unvalidatedFields = fieldsOfObject(openAPI, annotations)(obj)
         val fields            = validateFields(unvalidatedFields)
         val nested            =
@@ -1044,10 +1042,10 @@ final case class EndpointGen(config: Config) {
             enums = Nil,
           ),
         )
-      case JsonSchema.Object(_, _, _)                                                                  =>
-        // properties.isEmpty && additionalProperties.isRight
+      case JsonSchema.Object(_, _, _)                                          =>
+        // if obt.isOpenDictionary
         throw new IllegalArgumentException("Top-level maps are not supported")
-      case JsonSchema.Enum(enums)                                                                      =>
+      case JsonSchema.Enum(enums)                                              =>
         Some(
           Code.File(
             List("component", name.capitalize + ".scala"),
diff --git a/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala b/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala
index 9fdc294750..967bd1630d 100644
--- a/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala
+++ b/zio-http/jvm/src/test/scala/zio/http/endpoint/openapi/OpenAPIGenSpec.scala
@@ -2812,6 +2812,13 @@ object OpenAPIGenSpec extends ZIOSpecDefault {
             |          "nestedOption" : {
             |            "$ref" : "#/components/schemas/Recursive"
             |          },
+            |          "nestedMap" : {
+            |            "type" : "object",
+            |            "properties" : {},
+            |            "additionalProperties" : {
+            |              "$ref" : "#/components/schemas/Recursive"
+            |            }
+            |          },
             |          "nestedList" : {
             |            "type" :
             |              "array",
@@ -2823,10 +2830,6 @@ object OpenAPIGenSpec extends ZIOSpecDefault {
             |            "$ref" : "#/components/schemas/NestedRecursive"
             |          }
             |        },
-            |        "additionalProperties" :
-            |          {
-            |          "$ref" : "#/components/schemas/Recursive"
-            |        },
             |        "required" : [
             |          "nestedOption",
             |          "nestedList",
diff --git a/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala b/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala
index 0d8c5dacbe..ed8e1bc284 100644
--- a/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala
+++ b/zio-http/shared/src/main/scala/zio/http/endpoint/openapi/JsonSchema.scala
@@ -1212,10 +1212,30 @@ object JsonSchema {
     additionalProperties: Either[Boolean, JsonSchema],
     required: Chunk[java.lang.String],
   ) extends JsonSchema {
+
+    /**
+     * This Object represents an "open dictionary", aka a Map
+     *
+     * See: https://github.com/zio/zio-http/issues/3048#issuecomment-2306291192
+     */
+    def isOpenDictionary: Boolean = properties.isEmpty && additionalProperties.isRight
+
+    /**
+     * This Object represents a "closed dictionary", aka a case class
+     *
+     * See: https://github.com/zio/zio-http/issues/3048#issuecomment-2306291192
+     */
+    def isClosedDictionary: Boolean = additionalProperties.isLeft
+
+    /**
+     * Can't represent a case class and a Map at the same time
+     */
+    def isInvalid: Boolean = properties.nonEmpty && additionalProperties.isRight
+
     def addAll(value: Chunk[(java.lang.String, JsonSchema)]): Object =
       value.foldLeft(this) { case (obj, (name, schema)) =>
         schema match {
-          case Object(properties, additionalProperties, required) =>
+          case thatObj @ Object(properties, additionalProperties, required) if thatObj.isClosedDictionary =>
             obj.copy(
               properties = obj.properties ++ properties,
               additionalProperties = combineAdditionalProperties(obj.additionalProperties, additionalProperties),