Merge pull request softwaremill#1742 from borissmidt/master

softwaremill#1737 Input annotated class can be empty.
jchyb · Dec 22, 2022 · f4d8389 · f4d8389
2 parents ee62d08 + 17e627a
commit f4d8389
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Showing 6 changed files with 23 additions and 11 deletions.
diff --git a/core/src/main/scala-2/sttp/tapir/internal/EndpointAnnotationsMacro.scala b/core/src/main/scala-2/sttp/tapir/internal/EndpointAnnotationsMacro.scala
@@ -32,9 +32,6 @@ private[tapir] abstract class EndpointAnnotationsMacro(val c: blackbox.Context)
   protected val securitySchemeNameType = c.weakTypeOf[securitySchemeName]
 
   protected def validateCaseClass[A](util: CaseClassUtil[c.type, A]): Unit = {
-    if (util.fields.isEmpty) {
-      c.abort(c.enclosingPosition, "Case class must have at least one field")
-    }
     if (1 < util.fields.flatMap(bodyAnnotation).size) {
       c.abort(c.enclosingPosition, "No more than one body annotation is allowed")
     }
@@ -114,8 +111,10 @@ private[tapir] abstract class EndpointAnnotationsMacro(val c: blackbox.Context)
       }
 
       q"(t: $tupleType) => $className(..$ctorArgs)"
-    } else {
+    } else if (inputIdxToFieldIdx.size == 1) {
       q"(t: ${util.fields.head.info}) => $className(t)"
+    } else {
+      q"(t: ${}) => $className()"
     }
   }
 

diff --git a/core/src/main/scala-2/sttp/tapir/internal/EndpointOutputAnnotationsMacro.scala b/core/src/main/scala-2/sttp/tapir/internal/EndpointOutputAnnotationsMacro.scala
@@ -18,7 +18,9 @@ private[tapir] class EndpointOutputAnnotationsMacro(override val c: blackbox.Con
   def generateEndpointOutput[A: c.WeakTypeTag]: c.Expr[EndpointOutput[A]] = {
     val util = new CaseClassUtil[c.type, A](c, "response endpoint")
     validateCaseClass(util)
-
+    if (util.fields.isEmpty) {
+      c.abort(c.enclosingPosition, "Case class must have at least one field")
+    }
     val outputs = util.fields map { field =>
       val output = util
         .extractOptStringArgFromAnnotation(field, headerType)

diff --git a/core/src/main/scala-2/sttp/tapir/internal/MapToMacro.scala b/core/src/main/scala-2/sttp/tapir/internal/MapToMacro.scala
@@ -34,8 +34,9 @@ private[tapir] object MapToMacro {
     val caseClassUtil = new CaseClassUtil[c.type, CASE_CLASS](c, "mapTo mapping")
     val tupleType = weakTypeOf[TUPLE]
     val tupleTypeArgs = tupleType.dealias.typeArgs
-
-    if (caseClassUtil.fields.size == 1) {
+    if (caseClassUtil.fields.size == 0) {
+      q"(t: ${tupleType.dealias}) => ${caseClassUtil.className}()"
+    } else if (caseClassUtil.fields.size == 1) {
       verifySingleFieldCaseClass(c)(caseClassUtil, tupleType)
       // Compilation failure if `CaseClass` gets passed as `[Wrapper.CaseClass]` caused by invalid `className`
       // retrieval below, workaround available (see: https://github.com/softwaremill/tapir/issues/2540)
@@ -54,10 +55,8 @@ private[tapir] object MapToMacro {
 
     val caseClassUtil = new CaseClassUtil[c.type, CASE_CLASS](c, "mapTo mapping")
     val tupleType = weakTypeOf[TUPLE]
-
     if (caseClassUtil.fields.size == 1) {
       verifySingleFieldCaseClass(c)(caseClassUtil, tupleType)
-
     } else {
       verifyCaseClassMatchesTuple(c)(caseClassUtil, tupleType, tupleType.dealias.typeArgs)
     }
@@ -85,7 +84,7 @@ private[tapir] object MapToMacro {
       tupleTypeArgs: List[c.Type]
   ): Unit = {
     val tupleSymbol = tupleType.typeSymbol
-    if (!tupleSymbol.fullName.startsWith("scala.Tuple")) {
+    if (!tupleSymbol.fullName.startsWith("scala.Tuple") && caseClassUtil.fields.nonEmpty) {
       c.abort(c.enclosingPosition, s"Expected source type to be a tuple, but got: $tupleType")
     }
 

diff --git a/core/src/main/scala-3/sttp/tapir/internal/AnnotationsMacros.scala b/core/src/main/scala-3/sttp/tapir/internal/AnnotationsMacros.scala
@@ -447,7 +447,9 @@ private[tapir] class AnnotationsMacros[T <: Product: Type](using q: Quotes) {
       Select.unique(tExpr.asTerm, field.name).asExprOf[Any]
     }
 
-    if (inputIdxToFieldIdx.size > 1) {
+    if (inputIdxToFieldIdx.size == 0) {
+      '{ (t: T) => ().asInstanceOf[A] }
+    } else if (inputIdxToFieldIdx.size > 1) {
       '{ (t: T) => ${ Expr.ofTupleFromSeq(tupleArgs('t)) }.asInstanceOf[A] }
     } else {
       '{ (t: T) => ${ tupleArgs('t).head }.asInstanceOf[A] }

diff --git a/core/src/main/scala-3/sttp/tapir/internal/MappingMacros.scala b/core/src/main/scala-3/sttp/tapir/internal/MappingMacros.scala
@@ -15,6 +15,7 @@ private[tapir] object MappingMacros {
         case _        => mc.fromProduct(Tuple1(t))
       }
     def from(out: Out): In = Tuple.fromProduct(out) match {
+      case EmptyTuple    => EmptyTuple.asInstanceOf[In]
       case Tuple1(value) => value.asInstanceOf[In]
       case value         => value.asInstanceOf[In]
     }
@@ -23,6 +24,7 @@ private[tapir] object MappingMacros {
 
   inline def checkFields[A, B](using m: Mirror.ProductOf[A]): Unit =
     inline (erasedValue[m.MirroredElemTypes], erasedValue[B]) match {
+      case _: (EmptyTuple, Unit)   => ()
       case _: (B *: EmptyTuple, B) => ()
       case _: (B, B)               => ()
       case e                       => ComplietimeErrors.reportIncorrectMapping[B, A]

diff --git a/core/src/test/scala/sttp/tapir/annotations/DeriveEndpointIOTest.scala b/core/src/test/scala/sttp/tapir/annotations/DeriveEndpointIOTest.scala
@@ -182,6 +182,9 @@ object TapirRequestTest16 {
   val testAttributeKey: AttributeKey[String] = AttributeKey[String]
 }
 
+@endpointInput("some/path")
+final case class TapirRequestTest17()
+
 class DeriveEndpointIOTest extends AnyFlatSpec with Matchers with TableDrivenPropertyChecks with Tapir {
 
   "@endpointInput" should "derive correct input for @query, @cookie, @header" in {
@@ -317,6 +320,11 @@ class DeriveEndpointIOTest extends AnyFlatSpec with Matchers with TableDrivenPro
     }
   }
 
+  it should "accept empty case classes when annotated with @endpointInput" in {
+    val expectedInput = ("some" / "path").mapTo[TapirRequestTest17]
+    compareTransputs(EndpointInput.derived[TapirRequestTest17], expectedInput) shouldBe true
+  }
+
   it should "not compile if there is field without annotation" in {
     assertDoesNotCompile("""
       final case class Test(