Support range/length refinement providers for enums (#1283)

Co-authored-by: Jakub Kozłowski <kubukoz@gmail.com>

CHANGELOG.md

@@ -1,5 +1,9 @@
 # 0.18.3
 
+* Support constraint traits on members targeting enums
+
+Although it's weird to allow it, it is actually supported in Smithy.
+
 * Tweak operation schema `*Input` and `*Output` functions
 
 Some schema visitor will adjust their behaviour if a shape is the input or the output of an operation. For this reason we have a `InputOutput` class with a `Input` and `Output` hint that you can add to schemas to adjust the behaviour. `OperationSchema` has functions to work on input schemas and output schemas of an operation. This change makes these functions automatically add the relevant hint.

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

@@ -0,0 +1,25 @@
+package smithy4s.example
+
+import smithy4s.Hints
+import smithy4s.Schema
+import smithy4s.ShapeId
+import smithy4s.ShapeTag
+import smithy4s.schema.Schema.struct
+
+/** @param card
+  *   FaceCard types
+  */
+final case class StructureConstrainingEnum(letter: Option[Letters] = None, card: Option[FaceCard] = None)
+
+object StructureConstrainingEnum extends ShapeTag.Companion[StructureConstrainingEnum] {
+  val id: ShapeId = ShapeId("smithy4s.example", "StructureConstrainingEnum")
+
+  val hints: Hints = Hints.empty
+
+  implicit val schema: Schema[StructureConstrainingEnum] = struct(
+    Letters.schema.validated(smithy.api.Length(min = Some(2L), max = None)).validated(smithy.api.Pattern(s"$$aaa$$")).optional[StructureConstrainingEnum]("letter", _.letter),
+    FaceCard.schema.validated(smithy.api.Range(min = None, max = Some(scala.math.BigDecimal(1.0)))).optional[StructureConstrainingEnum]("card", _.card),
+  ){
+    StructureConstrainingEnum.apply
+  }.withId(id).addHints(hints)
+}

modules/core/src/smithy4s/RefinementProvider.scala

@@ -18,6 +18,7 @@ package smithy4s
 
 import smithy.api.Length
 import smithy.api.Pattern
+import smithy.api.Range
 
 /**
    * Given a constraint of type C, an RefinementProvider can produce a Refinement that
@@ -39,9 +40,46 @@ trait RefinementProvider[C, A, B] { self =>
     }
 }
 
-object RefinementProvider {
+object RefinementProvider extends LowPriorityImplicits {
 
-  private abstract class SimpleImpl[C, A](implicit _tag: ShapeTag[C])
+  type Simple[C, A] = RefinementProvider[C, A, A]
+
+  implicit val stringLengthConstraint: Simple[Length, String] =
+    new LengthConstraint[String](_.length)
+
+  implicit val blobLengthConstraint: Simple[Length, Blob] =
+    new LengthConstraint[Blob](_.size)
+
+  implicit def iterableLengthConstraint[C[_], A](implicit
+      ev: C[A] <:< Iterable[A]
+  ): Simple[Length, C[A]] =
+    new LengthConstraint[C[A]](ca => ev(ca).size)
+
+  implicit def mapLengthConstraint[K, V]: Simple[Length, Map[K, V]] =
+    new LengthConstraint[Map[K, V]](_.size)
+
+  implicit val stringPatternConstraints: Simple[Pattern, String] =
+    new PatternConstraint[String](identity)
+
+  implicit def numericRangeConstraints[N: Numeric]
+      : Simple[smithy.api.Range, N] = new RangeConstraint[N, N](identity[N])
+
+  // Lazy to avoid some pernicious recursive initialisation issue between
+  // the ShapeId static object and the generated code that makes use of it,
+  // as the `IdRef` type is referenced here.
+  //
+  // The problem only occurs in JS/Native.
+  lazy implicit val idRefRefinement
+      : RefinementProvider[smithy.api.IdRef, String, ShapeId] =
+    Refinement.drivenBy[smithy.api.IdRef](
+      ShapeId.parse(_: String) match {
+        case None        => Left("Invalid ShapeId")
+        case Some(value) => Right(value)
+      },
+      (_: ShapeId).show
+    )
+
+  private[smithy4s] abstract class SimpleImpl[C, A](implicit _tag: ShapeTag[C])
       extends RefinementProvider[C, A, A] {
 
     val tag: ShapeTag[C] = _tag
@@ -61,28 +99,7 @@ object RefinementProvider {
 
   }
 
-  type Simple[C, A] = RefinementProvider[C, A, A]
-
-  implicit def isomorphismConstraint[C, A, A0](implicit
-      constraintOnA: Simple[C, A],
-      iso: Bijection[A, A0]
-  ): Simple[C, A0] = constraintOnA.imapFull[A0, A0](iso, iso)
-
-  implicit val stringLengthConstraint: Simple[Length, String] =
-    new LengthConstraint[String](_.length)
-
-  implicit val blobLengthConstraint: Simple[Length, Blob] =
-    new LengthConstraint[Blob](_.size)
-
-  implicit def iterableLengthConstraint[C[_], A](implicit
-      ev: C[A] <:< Iterable[A]
-  ): Simple[Length, C[A]] =
-    new LengthConstraint[C[A]](ca => ev(ca).size)
-
-  implicit def mapLengthConstraint[K, V]: Simple[Length, Map[K, V]] =
-    new LengthConstraint[Map[K, V]](_.size)
-
-  private class LengthConstraint[A](getLength: A => Int)
+  private[smithy4s] class LengthConstraint[A](getLength: A => Int)
       extends SimpleImpl[Length, A] {
 
     def get(lengthHint: Length): A => Either[String, Unit] = { (a: A) =>
@@ -111,33 +128,31 @@ object RefinementProvider {
     }
   }
 
-  implicit val stringPatternConstraints: Simple[Pattern, String] =
-    new SimpleImpl[Pattern, String] {
-
-      def get(
-          pattern: Pattern
-      ): String => Either[String, Unit] = {
-        val regex = pattern.value.r
-        (input: String) =>
-          if (regex.findFirstIn(input).isDefined) Right(())
-          else
-            Left(
-              s"String '$input' does not match pattern '${pattern.value}'"
-            )
+  private[smithy4s] class PatternConstraint[E](getValue: E => String)
+      extends SimpleImpl[Pattern, E] {
+
+    def get(pattern: Pattern): E => Either[String, Unit] = {
+      val regex = pattern.value.r
+      (input: E) => {
+        val value = getValue(input)
+        if (regex.findFirstIn(getValue(input)).isDefined) Right(())
+        else
+          Left(
+            s"String '$value' does not match pattern '${pattern.value}'"
+          )
       }
-
     }
+  }
 
-  implicit def numericRangeConstraints[N: Numeric]
-      : Simple[smithy.api.Range, N] = new SimpleImpl[smithy.api.Range, N] {
-
+  private[smithy4s] class RangeConstraint[A, N: Numeric](getValue: A => N)
+      extends SimpleImpl[Range, A] {
     def get(
         range: smithy.api.Range
-    ): N => Either[String, Unit] = {
+    ): A => Either[String, Unit] = {
       val N = implicitly[Numeric[N]]
 
-      (n: N) =>
-        val value = BigDecimal(N.toDouble(n))
+      (a: A) =>
+        val value = BigDecimal(N.toDouble(getValue(a)))
         (range.min, range.max) match {
           case (Some(min), Some(max)) =>
             if (value >= min && value <= max) Right(())
@@ -162,18 +177,25 @@ object RefinementProvider {
     }
   }
 
-  // Lazy to avoid some pernicious recursive initialisation issue between
-  // the ShapeId static object and the generated code that makes use of it,
-  // as the `IdRef` type is referenced here.
-  //
-  // The problem only occurs in JS/Native.
-  lazy implicit val idRefRefinement
-      : RefinementProvider[smithy.api.IdRef, String, ShapeId] =
-    Refinement.drivenBy[smithy.api.IdRef](
-      ShapeId.parse(_: String) match {
-        case None        => Left("Invalid ShapeId")
-        case Some(value) => Right(value)
-      },
-      (_: ShapeId).show
-    )
+}
+
+private[smithy4s] trait LowPriorityImplicits {
+
+  implicit def enumLengthConstraint[E <: Enumeration.Value]
+      : RefinementProvider[Length, E, E] =
+    new RefinementProvider.LengthConstraint[E](e => e.value.size)
+
+  implicit def enumRangeConstraint[E <: Enumeration.Value]
+      : RefinementProvider[Range, E, E] =
+    new RefinementProvider.RangeConstraint[E, Int](e => e.intValue)
+
+  implicit def enumPatternConstraint[E <: Enumeration.Value]
+      : RefinementProvider[Pattern, E, E] =
+    new RefinementProvider.PatternConstraint[E](e => e.value)
+
+  implicit def isomorphismConstraint[C, A, A0](implicit
+      constraintOnA: RefinementProvider.Simple[C, A],
+      iso: Bijection[A, A0]
+  ): RefinementProvider[C, A0, A0] = constraintOnA.imapFull[A0, A0](iso, iso)
+
 }

sampleSpecs/constrainedEnum.smithy

@@ -0,0 +1,15 @@
+$version: "2"
+
+namespace smithy4s.example
+
+// see https://github.com/disneystreaming/smithy4s/issues/1282
+// We're testing that the render code compiles correctly, which
+// depends on the presence of a RefinementProvider between Range
+// and an enumeration value.
+structure StructureConstrainingEnum {
+    @length(min: 2)
+    @pattern("$aaa$")
+    letter: Letters
+    @range(max: 1)
+    card: FaceCard
+}