Fix OpenAPI schema generation when the discriminator field is an enum (…

…#4379)
softwaremill · Feb 27, 2025 · b47e8b8 · b47e8b8
1 parent ae19885
commit b47e8b8
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Showing 4 changed files with 108 additions and 1 deletion.
diff --git a/docs/apispec-docs/src/main/scala/sttp/tapir/docs/apispec/schema/ToKeyedSchemas.scala b/docs/apispec-docs/src/main/scala/sttp/tapir/docs/apispec/schema/ToKeyedSchemas.scala
@@ -1,6 +1,6 @@
 package sttp.tapir.docs.apispec.schema
 
-import sttp.tapir.Schema.Title
+import sttp.tapir.Schema.{EncodedDiscriminatorValue, Title}
 import sttp.tapir.{Codec, Schema => TSchema, SchemaType => TSchemaType}
 
 private[docs] object ToKeyedSchemas {
@@ -53,6 +53,8 @@ private[docs] object ToKeyedSchemas {
     if (s1.deprecated != s2.deprecated) result = result.deprecated(false)
     if (s1.attributes.get(Title.Attribute) != s2.attributes.get(Title.Attribute))
       result = result.copy(attributes = result.attributes.remove(Title.Attribute))
+    if (s1.attributes.get(EncodedDiscriminatorValue.Attribute) != s2.attributes.get(EncodedDiscriminatorValue.Attribute))
+      result = result.copy(attributes = result.attributes.remove(EncodedDiscriminatorValue.Attribute))
     result
   }
 }
diff --git a/docs/openapi-docs/src/test/resources/coproduct/expected_coproduct_discriminator_enum.yml b/docs/openapi-docs/src/test/resources/coproduct/expected_coproduct_discriminator_enum.yml
@@ -0,0 +1,63 @@
+openapi: 3.1.0
+info:
+  title: title
+  version: '1.0'
+paths:
+  /figure:
+    post:
+      operationId: postFigure
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/Pet'
+        required: true
+      responses:
+        '200':
+          description: ''
+        '400':
+          description: 'Invalid value for: body'
+          content:
+            text/plain:
+              schema:
+                type: string
+components:
+  schemas:
+    Cat:
+      title: Cat
+      type: object
+      required:
+      - name
+      - petType
+      properties:
+        name:
+          type: string
+        petType:
+          $ref: '#/components/schemas/PetType'
+    Dog:
+      title: Dog
+      type: object
+      required:
+      - breed
+      - petType
+      properties:
+        breed:
+          type: string
+        petType:
+          $ref: '#/components/schemas/PetType'
+    Pet:
+      title: Pet
+      oneOf:
+      - $ref: '#/components/schemas/Cat'
+      - $ref: '#/components/schemas/Dog'
+      discriminator:
+        propertyName: petType
+        mapping:
+          Canine: '#/components/schemas/Dog'
+          Feline: '#/components/schemas/Cat'
+    PetType:
+      title: PetType
+      type: string
+      enum:
+      - Canine
+      - Feline
diff --git a/docs/openapi-docs/src/test/scalajvm/sttp/tapir/docs/openapi/VerifyYamlCoproductTest.scala b/docs/openapi-docs/src/test/scalajvm/sttp/tapir/docs/openapi/VerifyYamlCoproductTest.scala
@@ -167,4 +167,16 @@ class VerifyYamlCoproductTest extends AnyFunSuite with Matchers {
 
     noIndentation(actualYaml) shouldBe expectedYaml
   }
+
+  test("coproduct using an enum discriminator, added using `.addDiscriminatorField`") {
+    val petEndpoint = endpoint.post
+      .in("figure")
+      .in(jsonBody[Pet])
+
+    val expectedYaml = load("coproduct/expected_coproduct_discriminator_enum.yml")
+
+    val actualYaml = OpenAPIDocsInterpreter().toOpenAPI(List(petEndpoint), "title", "1.0").toYaml
+
+    noIndentation(actualYaml) shouldBe expectedYaml
+  }
 }
diff --git a/...api-docs/src/test/scalajvm/sttp/tapir/docs/openapi/dtos/VerifyYamlCoproductTestData.scala b/...api-docs/src/test/scalajvm/sttp/tapir/docs/openapi/dtos/VerifyYamlCoproductTestData.scala
@@ -2,6 +2,10 @@ package sttp.tapir.docs.openapi.dtos
 
 import sttp.tapir.tests.data.Entity
 import sttp.tapir.{Schema, Validator}
+import sttp.tapir.SchemaType.SRef
+import sttp.tapir.Schema.SName
+import sttp.tapir.SchemaType
+import sttp.tapir.FieldName
 
 // TODO: move back to VerifyYamlTest companion after https://github.com/lampepfl/dotty/issues/12849 is fixed
 object VerifyYamlCoproductTestData {
@@ -24,4 +28,30 @@ object VerifyYamlCoproductTestData {
   }
 
   case class Square(color: Color.Value, shapeType: String = "square") extends Shape
+
+  sealed trait PetType
+  object PetType {
+    case object Canine extends PetType
+    case object Feline extends PetType
+    implicit val schema: Schema[PetType] = Schema.derivedEnumeration[PetType].defaultStringBased
+  }
+
+  sealed trait Pet
+  object Pet {
+    implicit val schema: Schema[Pet] = {
+      val derived = Schema.derived[Pet]
+      val mapping = Map(
+        PetType.Canine.toString -> SRef(SName("sttp.tapir.docs.openapi.dtos.VerifyYamlCoproductTestData.Dog")),
+        PetType.Feline.toString -> SRef(SName("sttp.tapir.docs.openapi.dtos.VerifyYamlCoproductTestData.Cat"))
+      )
+
+      derived.schemaType match {
+        case s: SchemaType.SCoproduct[Pet] =>
+          derived.copy(schemaType = s.addDiscriminatorField(FieldName("petType"), PetType.schema, mapping))
+        case _ => derived
+      }
+    }
+  }
+  final case class Dog(breed: String) extends Pet
+  final case class Cat(name: String) extends Pet
 }