Adding uniqueItems property to Set schemas (#3604)

core/src/main/scala/sttp/tapir/Schema.scala

@@ -301,6 +301,8 @@ object Schema extends LowPrioritySchema with SchemaCompanionMacros {
   implicit def schemaForOption[T: Schema]: Schema[Option[T]] = implicitly[Schema[T]].asOption
   implicit def schemaForArray[T: Schema]: Schema[Array[T]] = implicitly[Schema[T]].asArray
   implicit def schemaForIterable[T: Schema, C[X] <: Iterable[X]]: Schema[C[T]] = implicitly[Schema[T]].asIterable[C]
+  implicit def schemaForSet[T: Schema, C[X] <: scala.collection.Set[X]]: Schema[C[T]] = 
+    schemaForIterable[T, C].attribute(Schema.UniqueItems.Attribute, Schema.UniqueItems(true))
   implicit def schemaForPart[T: Schema]: Schema[Part[T]] = implicitly[Schema[T]].map(_ => None)(_.body)
 
   implicit def schemaForEither[A, B](implicit sa: Schema[A], sb: Schema[B]): Schema[Either[A, B]] = {
@@ -337,6 +339,11 @@ object Schema extends LowPrioritySchema with SchemaCompanionMacros {
   object Title {
     val Attribute: AttributeKey[Title] = new AttributeKey[Title]("sttp.tapir.Schema.Title")
   }
+
+  case class UniqueItems(uniqueItems: Boolean)
+  object UniqueItems {
+    val Attribute: AttributeKey[UniqueItems] = new AttributeKey[UniqueItems]("sttp.tapir.Schema.UniqueItems")
+  }
 
   /** @param typeParameterShortNames
     *   full name of type parameters, name is legacy and kept only for backward compatibility

docs/apispec-docs/src/main/scala/sttp/tapir/docs/apispec/schema/TSchemaToASchema.scala

@@ -1,7 +1,7 @@
 package sttp.tapir.docs.apispec.schema
 
 import sttp.apispec.{Schema => ASchema, _}
-import sttp.tapir.Schema.{SName, Title}
+import sttp.tapir.Schema.{SName, Title, UniqueItems}
 import sttp.tapir.Validator.EncodeToRaw
 import sttp.tapir.docs.apispec.DocsExtensionAttribute.RichSchema
 import sttp.tapir.docs.apispec.schema.TSchemaToASchema.{tDefaultToADefault, tExampleToAExample}
@@ -84,7 +84,7 @@ private[docs] class TSchemaToASchema(
       var s = result
       s = if (nullable) s.copy(nullable = Some(true)) else s
       s = addMetadata(s, schema)
-      s = addTitle(s, schema)
+      s = addAttributes(s, schema)
       s = addConstraints(s, primitiveValidators, schemaIsWholeNumber)
       s
     } else result
@@ -97,12 +97,14 @@ private[docs] class TSchemaToASchema(
       .toListMap
   }
 
-  private def addTitle(oschema: ASchema, tschema: TSchema[_]): ASchema = {
-    val fromAttr = tschema.attributes.get(Title.Attribute).map(_.value)
+  private def addAttributes(oschema: ASchema, tschema: TSchema[_]): ASchema = {
+    val titleFromAttr = tschema.attributes.get(Title.Attribute).map(_.value)
     // The primary motivation for using schema name as fallback title is to improve Swagger UX with
     // `oneOf` schemas in OpenAPI 3.1. See https://github.com/softwaremill/tapir/issues/3447 for details.
-    def fallback = tschema.name.map(fallbackSchemaTitle)
-    oschema.copy(title = fromAttr orElse fallback)
+    def fallbackTitle = tschema.name.map(fallbackSchemaTitle)
+    oschema
+      .copy(title = titleFromAttr orElse fallbackTitle)
+      .copy(uniqueItems = tschema.attribute(UniqueItems.Attribute).map(_.uniqueItems))
   }
 
   private def addMetadata(oschema: ASchema, tschema: TSchema[_]): ASchema = {

docs/openapi-docs/src/test/resources/expected_unfolded_array_with_unique_items.yml

@@ -0,0 +1,38 @@
+openapi: 3.1.0
+info:
+  title: Entities
+  version: '1.0'
+paths:
+  /:
+    get:
+      operationId: getRoot
+      responses:
+        '200':
+          description: ''
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ObjectWithSet'
+components:
+  schemas:
+    FruitAmount:
+      title: FruitAmount
+      required:
+        - fruit
+        - amount
+      type: object
+      properties:
+        fruit:
+          type: string
+        amount:
+          type: integer
+          format: int32
+    ObjectWithSet:
+      title: ObjectWithSet
+      type: object
+      properties:
+        data:
+          type: array
+          items:
+            $ref: '#/components/schemas/FruitAmount'
+          uniqueItems: true

docs/openapi-docs/src/test/scalajvm/sttp/tapir/docs/openapi/VerifyYamlTest.scala

@@ -313,6 +313,15 @@ class VerifyYamlTest extends AnyFunSuite with Matchers {
     actualYamlNoIndent shouldBe expectedYaml
   }
 
+  test("should add uniqueItems for set-based array schema") {
+    val expectedYaml = load("expected_unfolded_array_with_unique_items.yml")
+
+    val actualYaml = OpenAPIDocsInterpreter().toOpenAPI(endpoint.out(jsonBody[ObjectWithSet]), Info("Entities", "1.0")).toYaml
+    val actualYamlNoIndent = noIndentation(actualYaml)
+
+    actualYamlNoIndent shouldBe expectedYaml
+  }
+
   test("use fixed status code output in response") {
     val expectedYaml = load("expected_fixed_status_code.yml")
 

docs/openapi-docs/src/test/scalajvm/sttp/tapir/docs/openapi/dtos/VerifyYamlTestData.scala

@@ -8,6 +8,7 @@ object VerifyYamlTestData {
   case class G[T](data: T)
   case class ObjectWrapper(value: FruitAmount)
   case class ObjectWithList(data: List[FruitAmount])
+  case class ObjectWithSet(data: Set[FruitAmount])
   case class ObjectWithOption(data: Option[FruitAmount])
   case class ObjectWithDefaults(@default("foo") name: String, @default(12) count: Int)
 }

project/Versions.scala

@@ -11,7 +11,7 @@ object Versions {
   val sttp = "3.9.4"
   val sttpModel = "1.7.7"
   val sttpShared = "1.3.17"
-  val sttpApispec = "0.7.4"
+  val sttpApispec = "0.8.0"
   val akkaHttp = "10.2.10"
   val akkaStreams = "2.6.20"
   val pekkoHttp = "1.0.1"