Add support for @nullable trait in order to support MergePatch usecases

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 * Supports error responses with `@httpResponseCode` fields.
 
+* Added support for `@nullable` on fields, to allow absent values to be handled differently from explicit null
+
 # 0.18.8
 
 * Fix collision avoidance algorithm to cover Scala 3 keywords

modules/bootstrapped/src/generated/smithy4s/example/CustomErrorMessageType.scala

@@ -0,0 +1,15 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Newtype
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.schema.Schema.bijection
+import smithy4s.schema.Schema.string
+
+object CustomErrorMessageType extends Newtype[String] {
+  val id: ShapeId = ShapeId("smithy4s.example", "CustomErrorMessageType")
+  val hints: Hints = Hints.empty
+  val underlyingSchema: Schema[String] = string.withId(id).addHints(hints)
+  implicit val schema: Schema[CustomErrorMessageType] = bijection(underlyingSchema, asBijection)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorCustomTypeMessage.scala

@@ -0,0 +1,26 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.struct
+
+final case class ErrorCustomTypeMessage(message: Option[CustomErrorMessageType] = None) extends Smithy4sThrowable {
+  override def getMessage(): String = message.map(_.value).orNull
+}
+
+object ErrorCustomTypeMessage extends ShapeTag.Companion[ErrorCustomTypeMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorCustomTypeMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.SERVER.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorCustomTypeMessage] = struct(
+    CustomErrorMessageType.schema.optional[ErrorCustomTypeMessage]("message", _.message),
+  ){
+    ErrorCustomTypeMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorCustomTypeRequiredMessage.scala

@@ -0,0 +1,26 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.struct
+
+final case class ErrorCustomTypeRequiredMessage(message: CustomErrorMessageType) extends Smithy4sThrowable {
+  override def getMessage(): String = message.value
+}
+
+object ErrorCustomTypeRequiredMessage extends ShapeTag.Companion[ErrorCustomTypeRequiredMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorCustomTypeRequiredMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.SERVER.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorCustomTypeRequiredMessage] = struct(
+    CustomErrorMessageType.schema.required[ErrorCustomTypeRequiredMessage]("message", _.message),
+  ){
+    ErrorCustomTypeRequiredMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorNullableCustomTypeMessage.scala

@@ -0,0 +1,27 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Nullable
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.struct
+
+final case class ErrorNullableCustomTypeMessage(message: Option[Nullable[CustomErrorMessageType]] = None) extends Smithy4sThrowable {
+  override def getMessage(): String = message.flatMap(_.toOption).map(_.value).orNull
+}
+
+object ErrorNullableCustomTypeMessage extends ShapeTag.Companion[ErrorNullableCustomTypeMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorNullableCustomTypeMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.SERVER.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorNullableCustomTypeMessage] = struct(
+    CustomErrorMessageType.schema.nullable.optional[ErrorNullableCustomTypeMessage]("message", _.message),
+  ){
+    ErrorNullableCustomTypeMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorNullableCustomTypeRequiredMessage.scala

@@ -0,0 +1,27 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Nullable
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.struct
+
+final case class ErrorNullableCustomTypeRequiredMessage(message: Nullable[CustomErrorMessageType]) extends Smithy4sThrowable {
+  override def getMessage(): String = message.toOption.map(_.value).orNull
+}
+
+object ErrorNullableCustomTypeRequiredMessage extends ShapeTag.Companion[ErrorNullableCustomTypeRequiredMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorNullableCustomTypeRequiredMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.SERVER.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorNullableCustomTypeRequiredMessage] = struct(
+    CustomErrorMessageType.schema.nullable.required[ErrorNullableCustomTypeRequiredMessage]("message", _.message),
+  ){
+    ErrorNullableCustomTypeRequiredMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorNullableMessage.scala

@@ -0,0 +1,28 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Nullable
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.string
+import smithy4s.schema.Schema.struct
+
+final case class ErrorNullableMessage(message: Option[Nullable[String]] = None) extends Smithy4sThrowable {
+  override def getMessage(): String = message.flatMap(_.toOption).orNull
+}
+
+object ErrorNullableMessage extends ShapeTag.Companion[ErrorNullableMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorNullableMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.CLIENT.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorNullableMessage] = struct(
+    string.nullable.optional[ErrorNullableMessage]("message", _.message),
+  ){
+    ErrorNullableMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorNullableRequiredMessage.scala

@@ -0,0 +1,28 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Nullable
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.string
+import smithy4s.schema.Schema.struct
+
+final case class ErrorNullableRequiredMessage(message: Nullable[String]) extends Smithy4sThrowable {
+  override def getMessage(): String = message.toOption.orNull
+}
+
+object ErrorNullableRequiredMessage extends ShapeTag.Companion[ErrorNullableRequiredMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorNullableRequiredMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.SERVER.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorNullableRequiredMessage] = struct(
+    string.nullable.required[ErrorNullableRequiredMessage]("message", _.message),
+  ){
+    ErrorNullableRequiredMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/ErrorRequiredMessage.scala

@@ -0,0 +1,27 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.Smithy4sThrowable
+import smithy4s.schema.Schema.string
+import smithy4s.schema.Schema.struct
+
+final case class ErrorRequiredMessage(message: String) extends Smithy4sThrowable {
+  override def getMessage(): String = message
+}
+
+object ErrorRequiredMessage extends ShapeTag.Companion[ErrorRequiredMessage] {
+  val id: ShapeId = ShapeId("smithy4s.example", "ErrorRequiredMessage")
+
+  val hints: Hints = Hints(
+    smithy.api.Error.CLIENT.widen,
+  ).lazily
+
+  implicit val schema: Schema[ErrorRequiredMessage] = struct(
+    string.required[ErrorRequiredMessage]("message", _.message),
+  ){
+    ErrorRequiredMessage.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/Patchable.scala

@@ -0,0 +1,23 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Nullable
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.schema.Schema.int
+import smithy4s.schema.Schema.struct
+
+final case class Patchable(allowExplicitNull: Option[Nullable[Int]] = None)
+
+object Patchable extends ShapeTag.Companion[Patchable] {
+  val id: ShapeId = ShapeId("smithy4s.example", "Patchable")
+
+  val hints: Hints = Hints.empty
+
+  implicit val schema: Schema[Patchable] = struct(
+    int.nullable.optional[Patchable]("allowExplicitNull", _.allowExplicitNull),
+  ){
+    Patchable.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/PatchableEdgeCases.scala

@@ -0,0 +1,28 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Nullable
+import smithy4s.Nullable.Null
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.schema.Schema.int
+import smithy4s.schema.Schema.struct
+
+final case class PatchableEdgeCases(required: Nullable[Int], requiredDefaultValue: Nullable[Int] = smithy4s.Nullable.Value(3), requiredDefaultNull: Nullable[Int] = Null, defaultValue: Nullable[Int] = smithy4s.Nullable.Value(5), defaultNull: Nullable[Int] = Null)
+
+object PatchableEdgeCases extends ShapeTag.Companion[PatchableEdgeCases] {
+  val id: ShapeId = ShapeId("smithy4s.example", "PatchableEdgeCases")
+
+  val hints: Hints = Hints.empty
+
+  implicit val schema: Schema[PatchableEdgeCases] = struct(
+    int.nullable.required[PatchableEdgeCases]("required", _.required),
+    int.nullable.required[PatchableEdgeCases]("requiredDefaultValue", _.requiredDefaultValue).addHints(smithy.api.Default(smithy4s.Document.fromDouble(3.0d))),
+    int.nullable.required[PatchableEdgeCases]("requiredDefaultNull", _.requiredDefaultNull).addHints(smithy.api.Box(), smithy.api.Default(smithy4s.Document.nullDoc)),
+    int.nullable.field[PatchableEdgeCases]("defaultValue", _.defaultValue).addHints(smithy.api.Default(smithy4s.Document.fromDouble(5.0d))),
+    int.nullable.field[PatchableEdgeCases]("defaultNull", _.defaultNull).addHints(smithy.api.Box(), smithy.api.Default(smithy4s.Document.nullDoc)),
+  ){
+    PatchableEdgeCases.apply
+  }.withId(id).addHints(hints)
+}

modules/bootstrapped/src/generated/smithy4s/example/package.scala

@@ -90,6 +90,7 @@ package object example {
   type NonEmptyStrings = smithy4s.example.NonEmptyStrings.Type
   type TestStructurePattern = smithy4s.example.TestStructurePattern.Type
   type UnicodeRegexString = smithy4s.example.UnicodeRegexString.Type
+  type CustomErrorMessageType = smithy4s.example.CustomErrorMessageType.Type
   type UVIndex = smithy4s.example.UVIndex.Type
   @deprecated(message = "N/A", since = "N/A")
   type Strings = smithy4s.example.Strings.Type

modules/bootstrapped/test/src/smithy4s/ErrorMessageTraitSpec.scala

@@ -17,8 +17,7 @@
 package smithy4s
 
 import munit._
-import smithy4s.example.ClientError
-import smithy4s.example.ServerErrorCustomMessage
+import smithy4s.example._
 
 class ErrorMessageTraitSpec extends FunSuite {
 
@@ -34,6 +33,46 @@ class ErrorMessageTraitSpec extends FunSuite {
     )
   }
 
+  test(
+    "Custom @errorMessage field works for various nullable/default/required combos"
+  ) {
+    val customMessage = "some custom error message"
+    val errorsWithCustomMessage = List(
+      ErrorCustomTypeMessage(Some(CustomErrorMessageType(customMessage))),
+      ErrorCustomTypeRequiredMessage(CustomErrorMessageType(customMessage)),
+      ErrorNullableMessage(Some(Nullable.Value(customMessage))),
+      ErrorNullableRequiredMessage(Nullable.Value(customMessage)),
+      ErrorNullableCustomTypeMessage(
+        Some(Nullable.Value(CustomErrorMessageType(customMessage)))
+      ),
+      ErrorNullableCustomTypeRequiredMessage(
+        Nullable.Value(CustomErrorMessageType(customMessage))
+      ),
+      ErrorRequiredMessage(customMessage)
+    )
+    val errorsWithNullMessage = List(
+      ErrorCustomTypeMessage(None),
+      ErrorNullableMessage(None),
+      ErrorNullableMessage(Some(Nullable.Null)),
+      ErrorNullableRequiredMessage(Nullable.Null),
+      ErrorNullableCustomTypeMessage(None),
+      ErrorNullableCustomTypeMessage(Some(Nullable.Null)),
+      ErrorNullableCustomTypeRequiredMessage(Nullable.Null),
+      ServerErrorCustomMessage(None)
+    )
+
+    errorsWithCustomMessage.foreach(e =>
+      assertEquals(
+        e.getMessage,
+        customMessage,
+        s"Failed on ${e.getClass.getName}"
+      )
+    )
+    errorsWithNullMessage.foreach(e =>
+      assertEquals(e.getMessage, null, s"Failed on ${e.getClass.getName}")
+    )
+  }
+
   test("Generated getMessage") {
     val e = ClientError(400, "oopsy")