Fix recursive constraint violations with paths over list and map shapes (#2371)

* Fix recursive constraint violations with paths over list and map shapes

There is a widespread assumption throughout the generation of constraint
violations that does not hold true all the time, namely, that a
recursive constraint violation graph has the same requirements with
regards to boxing as the regular shape graph.

Some types corresponding to recursive shapes are boxed to introduce
indirection and thus not generate an infinitely recursive type. The
algorithm however does not superfluously introduce boxes when the cycle
goes through a list shape or a map shape. Why list shapes and map
shapes? List shapes and map shapes get rendered in Rust as `Vec<T>` and
`HashMap<K, V>`, respectively, they're the only Smithy shapes that
"organically" introduce indirection (via a pointer to the heap) in the
recursive path. For other recursive paths, we thus have to introduce the
indirection artificially ourselves using `Box`. This is done in the
`RecursiveShapeBoxer` model transform.

However, the constraint violation graph needs to box types in recursive
paths more often. Since we don't collect constraint violations
(yet, see #2040), the constraint violation graph never holds
`Vec<T>`s or `HashMap<K, V>`s, only simple types. Indeed, the following simple
recursive model:

```smithy
union Recursive {
    list: List
}

@length(min: 69)
list List {
    member: Recursive
}
```

has a cycle that goes through a list shape, so no shapes in it need
boxing in the regular shape graph. However, the constraint violation
graph is infinitely recursive if we don't introduce boxing somewhere:

```rust
pub mod model {
    pub mod list {
        pub enum ConstraintViolation {
            Length(usize),
            Member(
                usize,
                crate::model::recursive::ConstraintViolation,
            ),
        }
    }

    pub mod recursive {
        pub enum ConstraintViolation {
            List(crate::model::list::ConstraintViolation),
        }
    }
}
```

This commit fixes things by making the `RecursiveShapeBoxer` model
transform configurable so that the "cycles through lists and maps
introduce indirection" assumption can be lifted. This allows a server
model transform, `RecursiveConstraintViolationBoxer`, to tag member
shapes along recursive paths with a new trait,
`ConstraintViolationRustBoxTrait`, that the constraint violation type
generation then utilizes to ensure that no infinitely recursive
constraint violation types get generated.

For example, for the above model, the generated Rust code would now look
like:

```rust
pub mod model {
    pub mod list {
        pub enum ConstraintViolation {
            Length(usize),
            Member(
                usize,
                std::boxed::Box(crate::model::recursive::ConstraintViolation),
            ),
        }
    }

    pub mod recursive {
        pub enum ConstraintViolation {
            List(crate::model::list::ConstraintViolation),
        }
    }
}
```

Likewise, places where constraint violations are handled (like where
unconstrained types are converted to constrained types) have been
updated to account for the scenario where they now are or need to be
boxed.

Parametrized tests have been added to exhaustively test combinations of
models exercising recursive paths going through (sparse and non-sparse)
list and map shapes, as well as union and structure shapes
(`RecursiveConstraintViolationsTest`). These tests even assert that the
specific member shapes along the cycles are tagged as expected
(`RecursiveConstraintViolationBoxerTest`).

* Address comments
This commit is contained in:
david-perez 2023-02-15 23:09:37 +01:00 committed by GitHub
parent 6cade905f1
commit f9fb9e69d7
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
29 changed files with 480 additions and 79 deletions

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@ -105,14 +105,14 @@ class ClientCodegenVisitor(
// Add errors attached at the service level to the models
.let { ModelTransformer.create().copyServiceErrorsToOperations(it, settings.getService(it)) }
// Add `Box<T>` to recursive shapes as necessary
.let(RecursiveShapeBoxer::transform)
.let(RecursiveShapeBoxer()::transform)
// Normalize the `message` field on errors when enabled in settings (default: true)
.letIf(settings.codegenConfig.addMessageToErrors, AddErrorMessage::transform)
// NormalizeOperations by ensuring every operation has an input & output shape
.let(OperationNormalizer::transform)
// Drop unsupported event stream operations from the model
.let { RemoveEventStreamOperations.transform(it, settings) }
// - Normalize event stream operations
// Normalize event stream operations
.let(EventStreamNormalizer::transform)
/**

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@ -36,7 +36,7 @@ internal class ResiliencyConfigCustomizationTest {
@Test
fun `generates a valid config`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val project = TestWorkspace.testProject()
val codegenContext = testCodegenContext(model, settings = project.rustSettings())

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@ -12,7 +12,8 @@ import software.amazon.smithy.model.traits.Trait
/**
* Trait indicating that this shape should be represented with `Box<T>` when converted into Rust
*
* This is used to handle recursive shapes. See RecursiveShapeBoxer.
* This is used to handle recursive shapes.
* See [software.amazon.smithy.rust.codegen.core.smithy.transformers.RecursiveShapeBoxer].
*
* This trait is synthetic, applied during code generation, and never used in actual models.
*/

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@ -7,25 +7,50 @@ package software.amazon.smithy.rust.codegen.core.smithy.transformers
import software.amazon.smithy.codegen.core.TopologicalIndex
import software.amazon.smithy.model.Model
import software.amazon.smithy.model.shapes.ListShape
import software.amazon.smithy.model.shapes.CollectionShape
import software.amazon.smithy.model.shapes.MapShape
import software.amazon.smithy.model.shapes.MemberShape
import software.amazon.smithy.model.shapes.SetShape
import software.amazon.smithy.model.shapes.Shape
import software.amazon.smithy.model.transform.ModelTransformer
import software.amazon.smithy.rust.codegen.core.smithy.traits.RustBoxTrait
import software.amazon.smithy.rust.codegen.core.util.hasTrait
object RecursiveShapeBoxer {
class RecursiveShapeBoxer(
/**
* Transform a model which may contain recursive shapes into a model annotated with [RustBoxTrait]
* A predicate that determines when a cycle in the shape graph contains "indirection". If a cycle contains
* indirection, no shape needs to be tagged. What constitutes indirection is up to the caller to decide.
*/
private val containsIndirectionPredicate: (Collection<Shape>) -> Boolean = ::containsIndirection,
/**
* A closure that gets called on one member shape of a cycle that does not contain indirection for "fixing". For
* example, the [RustBoxTrait] trait can be used to tag the member shape.
*/
private val boxShapeFn: (MemberShape) -> MemberShape = ::addRustBoxTrait,
) {
/**
* Transform a model which may contain recursive shapes.
*
* When recursive shapes do NOT go through a List, Map, or Set, they must be boxed in Rust. This function will
* iteratively find loops & add the `RustBox` trait in a deterministic way until it reaches a fixed point.
* For example, when recursive shapes do NOT go through a `CollectionShape` or a `MapShape` shape, they must be
* boxed in Rust. This function will iteratively find cycles and call [boxShapeFn] on a member shape in the
* cycle to act on it. This is done in a deterministic way until it reaches a fixed point.
*
* This function MUST be deterministic (always choose the same shapes to `Box`). If it is not, that is a bug. Even so
* This function MUST be deterministic (always choose the same shapes to fix). If it is not, that is a bug. Even so
* this function may cause backward compatibility issues in certain pathological cases where a changes to recursive
* structures cause different members to be boxed. We may need to address these via customizations.
*
* For example, given the following model,
*
* ```smithy
* namespace com.example
*
* structure Recursive {
* recursiveStruct: Recursive
* anotherField: Boolean
* }
* ```
*
* The `com.example#Recursive$recursiveStruct` member shape is part of a cycle, but the
* `com.example#Recursive$anotherField` member shape is not.
*/
fun transform(model: Model): Model {
val next = transformInner(model)
@ -37,16 +62,17 @@ object RecursiveShapeBoxer {
}
/**
* If [model] contains a recursive loop that must be boxed, apply one instance of [RustBoxTrait] return the new model.
* If [model] contains no loops, return null.
* If [model] contains a recursive loop that must be boxed, return the transformed model resulting form a call to
* [boxShapeFn].
* If [model] contains no loops, return `null`.
*/
private fun transformInner(model: Model): Model? {
// Execute 1-step of the boxing algorithm in the path to reaching a fixed point
// 1. Find all the shapes that are part of a cycle
// 2. Find all the loops that those shapes are part of
// 3. Filter out the loops that go through a layer of indirection
// 3. Pick _just one_ of the remaining loops to fix
// 4. Select the member shape in that loop with the earliest shape id
// Execute 1 step of the boxing algorithm in the path to reaching a fixed point:
// 1. Find all the shapes that are part of a cycle.
// 2. Find all the loops that those shapes are part of.
// 3. Filter out the loops that go through a layer of indirection.
// 3. Pick _just one_ of the remaining loops to fix.
// 4. Select the member shape in that loop with the earliest shape id.
// 5. Box it.
// (External to this function) Go back to 1.
val index = TopologicalIndex.of(model)
@ -58,34 +84,38 @@ object RecursiveShapeBoxer {
// Flatten the connections into shapes.
loops.map { it.shapes }
}
val loopToFix = loops.firstOrNull { !containsIndirection(it) }
val loopToFix = loops.firstOrNull { !containsIndirectionPredicate(it) }
return loopToFix?.let { loop: List<Shape> ->
check(loop.isNotEmpty())
// pick the shape to box in a deterministic way
// Pick the shape to box in a deterministic way.
val shapeToBox = loop.filterIsInstance<MemberShape>().minByOrNull { it.id }!!
ModelTransformer.create().mapShapes(model) { shape ->
if (shape == shapeToBox) {
shape.asMemberShape().get().toBuilder().addTrait(RustBoxTrait()).build()
boxShapeFn(shape.asMemberShape().get())
} else {
shape
}
}
}
}
/**
* Check if a List<Shape> contains a shape which will use a pointer when represented in Rust, avoiding the
* need to add more Boxes
*/
private fun containsIndirection(loop: List<Shape>): Boolean {
return loop.find {
when (it) {
is ListShape,
is MapShape,
is SetShape, -> true
else -> it.hasTrait<RustBoxTrait>()
}
} != null
}
}
/**
* Check if a `List<Shape>` contains a shape which will use a pointer when represented in Rust, avoiding the
* need to add more `Box`es.
*
* Why `CollectionShape`s and `MapShape`s? Note that `CollectionShape`s get rendered in Rust as `Vec<T>`, and
* `MapShape`s as `HashMap<String, T>`; they're the only Smithy shapes that "organically" introduce indirection
* (via a pointer to the heap) in the recursive path. For other recursive paths, we thus have to introduce the
* indirection artificially ourselves using `Box`.
*
*/
private fun containsIndirection(loop: Collection<Shape>): Boolean = loop.find {
when (it) {
is CollectionShape, is MapShape -> true
else -> it.hasTrait<RustBoxTrait>()
}
} != null
private fun addRustBoxTrait(shape: MemberShape): MemberShape = shape.toBuilder().addTrait(RustBoxTrait()).build()

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@ -82,7 +82,7 @@ class InstantiatorTest {
@required
num: Integer
}
""".asSmithyModel().let { RecursiveShapeBoxer.transform(it) }
""".asSmithyModel().let { RecursiveShapeBoxer().transform(it) }
private val codegenContext = testCodegenContext(model)
private val symbolProvider = codegenContext.symbolProvider

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@ -313,7 +313,7 @@ class StructureGeneratorTest {
@Test
fun `it generates accessor methods`() {
val testModel =
RecursiveShapeBoxer.transform(
RecursiveShapeBoxer().transform(
"""
namespace test

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@ -42,7 +42,7 @@ class AwsQueryParserGeneratorTest {
@Test
fun `it modifies operation parsing to include Response and Result tags`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
val parserGenerator = AwsQueryParserGenerator(

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@ -42,7 +42,7 @@ class Ec2QueryParserGeneratorTest {
@Test
fun `it modifies operation parsing to include Response and Result tags`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
val parserGenerator = Ec2QueryParserGenerator(

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@ -114,7 +114,7 @@ class JsonParserGeneratorTest {
@Test
fun `generates valid deserializers`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
fun builderSymbol(shape: StructureShape): Symbol =

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@ -94,7 +94,7 @@ internal class XmlBindingTraitParserGeneratorTest {
@Test
fun `generates valid parsers`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
val parserGenerator = XmlBindingTraitParserGenerator(

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@ -92,7 +92,7 @@ class AwsQuerySerializerGeneratorTest {
true -> CodegenTarget.CLIENT
false -> CodegenTarget.SERVER
}
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model, codegenTarget = codegenTarget)
val symbolProvider = codegenContext.symbolProvider
val parserGenerator = AwsQuerySerializerGenerator(testCodegenContext(model, codegenTarget = codegenTarget))

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@ -85,7 +85,7 @@ class Ec2QuerySerializerGeneratorTest {
@Test
fun `generates valid serializers`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
val parserGenerator = Ec2QuerySerializerGenerator(codegenContext)

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@ -100,7 +100,7 @@ class JsonSerializerGeneratorTest {
@Test
fun `generates valid serializers`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
val parserSerializer = JsonSerializerGenerator(

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@ -105,7 +105,7 @@ internal class XmlBindingTraitSerializerGeneratorTest {
@Test
fun `generates valid serializers`() {
val model = RecursiveShapeBoxer.transform(OperationNormalizer.transform(baseModel))
val model = RecursiveShapeBoxer().transform(OperationNormalizer.transform(baseModel))
val codegenContext = testCodegenContext(model)
val symbolProvider = codegenContext.symbolProvider
val parserGenerator = XmlBindingTraitSerializerGenerator(

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@ -31,7 +31,7 @@ internal class RecursiveShapeBoxerTest {
hello: Hello
}
""".asSmithyModel()
RecursiveShapeBoxer.transform(model) shouldBe model
RecursiveShapeBoxer().transform(model) shouldBe model
}
@Test
@ -43,7 +43,7 @@ internal class RecursiveShapeBoxerTest {
anotherField: Boolean
}
""".asSmithyModel()
val transformed = RecursiveShapeBoxer.transform(model)
val transformed = RecursiveShapeBoxer().transform(model)
val member: MemberShape = transformed.lookup("com.example#Recursive\$RecursiveStruct")
member.expectTrait<RustBoxTrait>()
}
@ -70,7 +70,7 @@ internal class RecursiveShapeBoxerTest {
third: SecondTree
}
""".asSmithyModel()
val transformed = RecursiveShapeBoxer.transform(model)
val transformed = RecursiveShapeBoxer().transform(model)
val boxed = transformed.shapes().filter { it.hasTrait<RustBoxTrait>() }.toList()
boxed.map { it.id.toString().removePrefix("com.example#") }.toSet() shouldBe setOf(
"Atom\$add",

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@ -66,7 +66,7 @@ class RecursiveShapesIntegrationTest {
}
output.message shouldContain "has infinite size"
val fixedProject = check(RecursiveShapeBoxer.transform(model))
val fixedProject = check(RecursiveShapeBoxer().transform(model))
fixedProject.compileAndTest()
}
}

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@ -78,6 +78,7 @@ import software.amazon.smithy.rust.codegen.server.smithy.generators.protocol.Ser
import software.amazon.smithy.rust.codegen.server.smithy.protocols.ServerProtocolLoader
import software.amazon.smithy.rust.codegen.server.smithy.traits.isReachableFromOperationInput
import software.amazon.smithy.rust.codegen.server.smithy.transformers.AttachValidationExceptionToConstrainedOperationInputsInAllowList
import software.amazon.smithy.rust.codegen.server.smithy.transformers.RecursiveConstraintViolationBoxer
import software.amazon.smithy.rust.codegen.server.smithy.transformers.RemoveEbsModelValidationException
import software.amazon.smithy.rust.codegen.server.smithy.transformers.ShapesReachableFromOperationInputTagger
import java.util.logging.Logger
@ -162,7 +163,9 @@ open class ServerCodegenVisitor(
// Add errors attached at the service level to the models
.let { ModelTransformer.create().copyServiceErrorsToOperations(it, settings.getService(it)) }
// Add `Box<T>` to recursive shapes as necessary
.let(RecursiveShapeBoxer::transform)
.let(RecursiveShapeBoxer()::transform)
// Add `Box<T>` to recursive constraint violations as necessary
.let(RecursiveConstraintViolationBoxer::transform)
// Normalize operations by adding synthetic input and output shapes to every operation
.let(OperationNormalizer::transform)
// Remove the EBS model's own `ValidationException`, which collides with `smithy.framework#ValidationException`

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@ -9,12 +9,15 @@ import software.amazon.smithy.model.shapes.CollectionShape
import software.amazon.smithy.rust.codegen.core.rustlang.RustWriter
import software.amazon.smithy.rust.codegen.core.rustlang.Visibility
import software.amazon.smithy.rust.codegen.core.rustlang.join
import software.amazon.smithy.rust.codegen.core.rustlang.rust
import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
import software.amazon.smithy.rust.codegen.core.smithy.makeRustBoxed
import software.amazon.smithy.rust.codegen.core.smithy.module
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.core.util.letIf
import software.amazon.smithy.rust.codegen.server.smithy.PubCrateConstraintViolationSymbolProvider
import software.amazon.smithy.rust.codegen.server.smithy.ServerCodegenContext
import software.amazon.smithy.rust.codegen.server.smithy.canReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
import software.amazon.smithy.rust.codegen.server.smithy.traits.isReachableFromOperationInput
class CollectionConstraintViolationGenerator(
@ -38,16 +41,22 @@ class CollectionConstraintViolationGenerator(
private val constraintsInfo: List<TraitInfo> = collectionConstraintsInfo.map { it.toTraitInfo() }
fun render() {
val memberShape = model.expectShape(shape.member.target)
val targetShape = model.expectShape(shape.member.target)
val constraintViolationSymbol = constraintViolationSymbolProvider.toSymbol(shape)
val constraintViolationName = constraintViolationSymbol.name
val isMemberConstrained = memberShape.canReachConstrainedShape(model, symbolProvider)
val isMemberConstrained = targetShape.canReachConstrainedShape(model, symbolProvider)
val constraintViolationVisibility = Visibility.publicIf(publicConstrainedTypes, Visibility.PUBCRATE)
modelsModuleWriter.withInlineModule(constraintViolationSymbol.module()) {
val constraintViolationVariants = constraintsInfo.map { it.constraintViolationVariant }.toMutableList()
if (isMemberConstrained) {
constraintViolationVariants += {
val memberConstraintViolationSymbol =
constraintViolationSymbolProvider.toSymbol(targetShape).letIf(
shape.member.hasTrait<ConstraintViolationRustBoxTrait>(),
) {
it.makeRustBoxed()
}
rustTemplate(
"""
/// Constraint violation error when an element doesn't satisfy its own constraints.
@ -56,7 +65,7 @@ class CollectionConstraintViolationGenerator(
##[doc(hidden)]
Member(usize, #{MemberConstraintViolationSymbol})
""",
"MemberConstraintViolationSymbol" to constraintViolationSymbolProvider.toSymbol(memberShape),
"MemberConstraintViolationSymbol" to memberConstraintViolationSymbol,
)
}
}

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@ -11,10 +11,13 @@ import software.amazon.smithy.model.traits.LengthTrait
import software.amazon.smithy.rust.codegen.core.rustlang.RustWriter
import software.amazon.smithy.rust.codegen.core.rustlang.Visibility
import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
import software.amazon.smithy.rust.codegen.core.smithy.makeRustBoxed
import software.amazon.smithy.rust.codegen.core.smithy.module
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.core.util.letIf
import software.amazon.smithy.rust.codegen.server.smithy.PubCrateConstraintViolationSymbolProvider
import software.amazon.smithy.rust.codegen.server.smithy.ServerCodegenContext
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
import software.amazon.smithy.rust.codegen.server.smithy.traits.isReachableFromOperationInput
class MapConstraintViolationGenerator(
@ -47,7 +50,14 @@ class MapConstraintViolationGenerator(
constraintViolationCodegenScopeMutableList.add("KeyConstraintViolationSymbol" to constraintViolationSymbolProvider.toSymbol(keyShape))
}
if (isValueConstrained(valueShape, model, symbolProvider)) {
constraintViolationCodegenScopeMutableList.add("ValueConstraintViolationSymbol" to constraintViolationSymbolProvider.toSymbol(valueShape))
constraintViolationCodegenScopeMutableList.add(
"ValueConstraintViolationSymbol" to
constraintViolationSymbolProvider.toSymbol(valueShape).letIf(
shape.value.hasTrait<ConstraintViolationRustBoxTrait>(),
) {
it.makeRustBoxed()
},
)
constraintViolationCodegenScopeMutableList.add("KeySymbol" to constrainedShapeSymbolProvider.toSymbol(keyShape))
}
val constraintViolationCodegenScope = constraintViolationCodegenScopeMutableList.toTypedArray()

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@ -20,13 +20,13 @@ import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
import software.amazon.smithy.rust.codegen.core.smithy.isOptional
import software.amazon.smithy.rust.codegen.core.smithy.makeRustBoxed
import software.amazon.smithy.rust.codegen.core.smithy.traits.RustBoxTrait
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.core.util.letIf
import software.amazon.smithy.rust.codegen.core.util.toPascalCase
import software.amazon.smithy.rust.codegen.server.smithy.PubCrateConstraintViolationSymbolProvider
import software.amazon.smithy.rust.codegen.server.smithy.ServerCodegenContext
import software.amazon.smithy.rust.codegen.server.smithy.targetCanReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
/**
* Renders constraint violation types that arise when building a structure shape builder.
@ -138,8 +138,8 @@ class ServerBuilderConstraintViolations(
val constraintViolationSymbol =
constraintViolationSymbolProvider.toSymbol(targetShape)
// If the corresponding structure's member is boxed, box this constraint violation symbol too.
.letIf(constraintViolation.forMember.hasTrait<RustBoxTrait>()) {
// Box this constraint violation symbol if necessary.
.letIf(constraintViolation.forMember.hasTrait<ConstraintViolationRustBoxTrait>()) {
it.makeRustBoxed()
}

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@ -49,6 +49,7 @@ import software.amazon.smithy.rust.codegen.server.smithy.ServerRuntimeType
import software.amazon.smithy.rust.codegen.server.smithy.canReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.hasConstraintTraitOrTargetHasConstraintTrait
import software.amazon.smithy.rust.codegen.server.smithy.targetCanReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
import software.amazon.smithy.rust.codegen.server.smithy.traits.isReachableFromOperationInput
import software.amazon.smithy.rust.codegen.server.smithy.wouldHaveConstrainedWrapperTupleTypeWerePublicConstrainedTypesEnabled
@ -541,6 +542,8 @@ class ServerBuilderGenerator(
val hasBox = builderMemberSymbol(member)
.mapRustType { it.stripOuter<RustType.Option>() }
.isRustBoxed()
val errHasBox = member.hasTrait<ConstraintViolationRustBoxTrait>()
if (hasBox) {
writer.rustTemplate(
"""
@ -548,11 +551,6 @@ class ServerBuilderGenerator(
#{MaybeConstrained}::Constrained(x) => Ok(Box::new(x)),
#{MaybeConstrained}::Unconstrained(x) => Ok(Box::new(x.try_into()?)),
})
.map(|res|
res${ if (constrainedTypeHoldsFinalType(member)) "" else ".map(|v| v.into())" }
.map_err(|err| ConstraintViolation::${constraintViolation.name()}(Box::new(err)))
)
.transpose()?
""",
*codegenScope,
)
@ -563,16 +561,23 @@ class ServerBuilderGenerator(
#{MaybeConstrained}::Constrained(x) => Ok(x),
#{MaybeConstrained}::Unconstrained(x) => x.try_into(),
})
.map(|res|
res${if (constrainedTypeHoldsFinalType(member)) "" else ".map(|v| v.into())"}
.map_err(ConstraintViolation::${constraintViolation.name()})
)
.transpose()?
""",
*codegenScope,
)
}
writer.rustTemplate(
"""
.map(|res|
res${if (constrainedTypeHoldsFinalType(member)) "" else ".map(|v| v.into())"}
${if (errHasBox) ".map_err(Box::new)" else "" }
.map_err(ConstraintViolation::${constraintViolation.name()})
)
.transpose()?
""",
*codegenScope,
)
// Constrained types are not public and this is a member shape that would have generated a
// public constrained type, were the setting to be enabled.
// We've just checked the constraints hold by going through the non-public

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@ -19,11 +19,13 @@ import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
import software.amazon.smithy.rust.codegen.core.smithy.isOptional
import software.amazon.smithy.rust.codegen.core.smithy.makeMaybeConstrained
import software.amazon.smithy.rust.codegen.core.smithy.module
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.server.smithy.PubCrateConstraintViolationSymbolProvider
import software.amazon.smithy.rust.codegen.server.smithy.ServerCodegenContext
import software.amazon.smithy.rust.codegen.server.smithy.UnconstrainedShapeSymbolProvider
import software.amazon.smithy.rust.codegen.server.smithy.canReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.isDirectlyConstrained
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
/**
* Generates a Rust type for a constrained collection shape that is able to hold values for the corresponding
@ -107,7 +109,11 @@ class UnconstrainedCollectionGenerator(
constrainedShapeSymbolProvider.toSymbol(shape.member)
}
val innerConstraintViolationSymbol = constraintViolationSymbolProvider.toSymbol(innerShape)
val boxErr = if (shape.member.hasTrait<ConstraintViolationRustBoxTrait>()) {
".map_err(|(idx, inner_violation)| (idx, Box::new(inner_violation)))"
} else {
""
}
val constrainValueWritable = writable {
conditionalBlock("inner.map(|inner| ", ").transpose()", constrainedMemberSymbol.isOptional()) {
rust("inner.try_into().map_err(|inner_violation| (idx, inner_violation))")
@ -124,7 +130,9 @@ class UnconstrainedCollectionGenerator(
#{ConstrainValueWritable:W}
})
.collect();
let inner = res.map_err(|(idx, inner_violation)| Self::Error::Member(idx, inner_violation))?;
let inner = res
$boxErr
.map_err(|(idx, inner_violation)| Self::Error::Member(idx, inner_violation))?;
""",
"Vec" to RuntimeType.Vec,
"ConstrainedMemberSymbol" to constrainedMemberSymbol,

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@ -20,10 +20,12 @@ import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
import software.amazon.smithy.rust.codegen.core.smithy.isOptional
import software.amazon.smithy.rust.codegen.core.smithy.makeMaybeConstrained
import software.amazon.smithy.rust.codegen.core.smithy.module
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.server.smithy.PubCrateConstraintViolationSymbolProvider
import software.amazon.smithy.rust.codegen.server.smithy.ServerCodegenContext
import software.amazon.smithy.rust.codegen.server.smithy.canReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.isDirectlyConstrained
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
/**
* Generates a Rust type for a constrained map shape that is able to hold values for the corresponding
@ -125,6 +127,11 @@ class UnconstrainedMapGenerator(
)
}
val constrainValueWritable = writable {
val boxErr = if (shape.value.hasTrait<ConstraintViolationRustBoxTrait>()) {
".map_err(Box::new)"
} else {
""
}
if (constrainedMemberValueSymbol.isOptional()) {
// The map is `@sparse`.
rustBlock("match v") {
@ -133,7 +140,7 @@ class UnconstrainedMapGenerator(
// DRYing this up with the else branch below would make this less understandable.
rustTemplate(
"""
match #{ConstrainedValueSymbol}::try_from(v) {
match #{ConstrainedValueSymbol}::try_from(v)$boxErr {
Ok(v) => Ok((k, Some(v))),
Err(inner_constraint_violation) => Err(Self::Error::Value(k, inner_constraint_violation)),
}
@ -145,7 +152,7 @@ class UnconstrainedMapGenerator(
} else {
rustTemplate(
"""
match #{ConstrainedValueSymbol}::try_from(v) {
match #{ConstrainedValueSymbol}::try_from(v)$boxErr {
Ok(v) => #{Epilogue:W},
Err(inner_constraint_violation) => Err(Self::Error::Value(k, inner_constraint_violation)),
}
@ -214,9 +221,10 @@ class UnconstrainedMapGenerator(
// ```
rustTemplate(
"""
let hm: std::collections::HashMap<#{KeySymbol}, #{ValueSymbol}> =
let hm: #{HashMap}<#{KeySymbol}, #{ValueSymbol}> =
hm.into_iter().map(|(k, v)| (k, v.into())).collect();
""",
"HashMap" to RuntimeType.HashMap,
"KeySymbol" to symbolProvider.toSymbol(keyShape),
"ValueSymbol" to symbolProvider.toSymbol(valueShape),
)

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@ -33,6 +33,7 @@ import software.amazon.smithy.rust.codegen.server.smithy.ServerCodegenContext
import software.amazon.smithy.rust.codegen.server.smithy.canReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.isDirectlyConstrained
import software.amazon.smithy.rust.codegen.server.smithy.targetCanReachConstrainedShape
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
import software.amazon.smithy.rust.codegen.server.smithy.traits.isReachableFromOperationInput
/**
@ -171,8 +172,8 @@ class UnconstrainedUnionGenerator(
val constraintViolationSymbol =
constraintViolationSymbolProvider.toSymbol(targetShape)
// If the corresponding union's member is boxed, box this constraint violation symbol too.
.letIf(constraintViolation.forMember.hasTrait<RustBoxTrait>()) {
// Box this constraint violation symbol if necessary.
.letIf(constraintViolation.forMember.hasTrait<ConstraintViolationRustBoxTrait>()) {
it.makeRustBoxed()
}
@ -201,10 +202,15 @@ class UnconstrainedUnionGenerator(
(!publicConstrainedTypes || !targetShape.isDirectlyConstrained(symbolProvider))
val (unconstrainedVar, boxIt) = if (member.hasTrait<RustBoxTrait>()) {
"(*unconstrained)" to ".map(Box::new).map_err(Box::new)"
"(*unconstrained)" to ".map(Box::new)"
} else {
"unconstrained" to ""
}
val boxErr = if (member.hasTrait<ConstraintViolationRustBoxTrait>()) {
".map_err(Box::new)"
} else {
""
}
if (resolveToNonPublicConstrainedType) {
val constrainedSymbol =
@ -219,6 +225,7 @@ class UnconstrainedUnionGenerator(
let constrained: #{ConstrainedSymbol} = $unconstrainedVar
.try_into()
$boxIt
$boxErr
.map_err(Self::Error::${ConstraintViolation(member).name()})?;
constrained.into()
}
@ -231,6 +238,7 @@ class UnconstrainedUnionGenerator(
$unconstrainedVar
.try_into()
$boxIt
$boxErr
.map_err(Self::Error::${ConstraintViolation(member).name()})?
""",
)

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@ -0,0 +1,25 @@
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package software.amazon.smithy.rust.codegen.server.smithy.traits
import software.amazon.smithy.model.node.Node
import software.amazon.smithy.model.shapes.ShapeId
import software.amazon.smithy.model.traits.Trait
/**
* This shape is analogous to [software.amazon.smithy.rust.codegen.core.smithy.traits.RustBoxTrait], but for the
* constraint violation graph. The sets of shapes we tag are different, and they are interpreted by the code generator
* differently, so we need a separate tag.
*
* This is used to handle recursive constraint violations.
* See [software.amazon.smithy.rust.codegen.server.smithy.transformers.RecursiveConstraintViolationBoxer].
*/
class ConstraintViolationRustBoxTrait : Trait {
val ID = ShapeId.from("software.amazon.smithy.rust.codegen.smithy.rust.synthetic#constraintViolationBox")
override fun toNode(): Node = Node.objectNode()
override fun toShapeId(): ShapeId = ID
}

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@ -0,0 +1,78 @@
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package software.amazon.smithy.rust.codegen.server.smithy.transformers
import software.amazon.smithy.model.Model
import software.amazon.smithy.model.shapes.MemberShape
import software.amazon.smithy.model.shapes.Shape
import software.amazon.smithy.rust.codegen.core.smithy.transformers.RecursiveShapeBoxer
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
object RecursiveConstraintViolationBoxer {
/**
* Transform a model which may contain recursive shapes into a model annotated with [ConstraintViolationRustBoxTrait].
*
* See [RecursiveShapeBoxer] for how the tagging algorithm works.
*
* The constraint violation graph needs to box types in recursive paths more often. Since we don't collect
* constraint violations (yet, see [0]), the constraint violation graph never holds `Vec<T>`s or `HashMap<K, V>`s,
* only simple types. Indeed, the following simple recursive model:
*
* ```smithy
* union Recursive {
* list: List
* }
*
* @length(min: 69)
* list List {
* member: Recursive
* }
* ```
*
* has a cycle that goes through a list shape, so no shapes in it need boxing in the regular shape graph. However,
* the constraint violation graph is infinitely recursive if we don't introduce boxing somewhere:
*
* ```rust
* pub mod model {
* pub mod list {
* pub enum ConstraintViolation {
* Length(usize),
* Member(
* usize,
* crate::model::recursive::ConstraintViolation,
* ),
* }
* }
*
* pub mod recursive {
* pub enum ConstraintViolation {
* List(crate::model::list::ConstraintViolation),
* }
* }
* }
* ```
*
* So what we do to fix this is to configure the `RecursiveShapeBoxer` model transform so that the "cycles through
* lists and maps introduce indirection" assumption can be lifted. This allows this model transform to tag member
* shapes along recursive paths with a new trait, `ConstraintViolationRustBoxTrait`, that the constraint violation
* type generation then utilizes to ensure that no infinitely recursive constraint violation types get generated.
* Places where constraint violations are handled (like where unconstrained types are converted to constrained
* types) must account for the scenario where they now are or need to be boxed.
*
* [0] https://github.com/awslabs/smithy-rs/pull/2040
*/
fun transform(model: Model): Model = RecursiveShapeBoxer(
containsIndirectionPredicate = ::constraintViolationLoopContainsIndirection,
boxShapeFn = ::addConstraintViolationRustBoxTrait,
).transform(model)
private fun constraintViolationLoopContainsIndirection(loop: Collection<Shape>): Boolean =
loop.find { it.hasTrait<ConstraintViolationRustBoxTrait>() } != null
private fun addConstraintViolationRustBoxTrait(memberShape: MemberShape): MemberShape =
memberShape.toBuilder().addTrait(ConstraintViolationRustBoxTrait()).build()
}

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@ -0,0 +1,185 @@
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package software.amazon.smithy.rust.codegen.server.smithy
import org.junit.jupiter.api.extension.ExtensionContext
import org.junit.jupiter.params.ParameterizedTest
import org.junit.jupiter.params.provider.Arguments
import org.junit.jupiter.params.provider.ArgumentsProvider
import org.junit.jupiter.params.provider.ArgumentsSource
import software.amazon.smithy.model.Model
import software.amazon.smithy.rust.codegen.core.testutil.asSmithyModel
import software.amazon.smithy.rust.codegen.server.smithy.testutil.serverIntegrationTest
import java.util.stream.Stream
internal class RecursiveConstraintViolationsTest {
data class TestCase(
/** The test name is only used in the generated report, to easily identify a failing test. **/
val testName: String,
/** The model to generate **/
val model: Model,
/** The shape ID of the member shape that should have the marker trait attached. **/
val shapeIdWithConstraintViolationRustBoxTrait: String,
)
class RecursiveConstraintViolationsTestProvider : ArgumentsProvider {
private val baseModel =
"""
namespace com.amazonaws.recursiveconstraintviolations
use aws.protocols#restJson1
use smithy.framework#ValidationException
@restJson1
service RecursiveConstraintViolations {
operations: [
Operation
]
}
@http(uri: "/operation", method: "POST")
operation Operation {
input: Recursive
output: Recursive
errors: [ValidationException]
}
"""
private fun recursiveListModel(sparse: Boolean, listPrefix: String = ""): Pair<Model, String> =
"""
$baseModel
structure Recursive {
list: ${listPrefix}List
}
${ if (sparse) { "@sparse" } else { "" } }
@length(min: 69)
list ${listPrefix}List {
member: Recursive
}
""".asSmithyModel() to if ("${listPrefix}List" < "Recursive") {
"com.amazonaws.recursiveconstraintviolations#${listPrefix}List\$member"
} else {
"com.amazonaws.recursiveconstraintviolations#Recursive\$list"
}
private fun recursiveMapModel(sparse: Boolean, mapPrefix: String = ""): Pair<Model, String> =
"""
$baseModel
structure Recursive {
map: ${mapPrefix}Map
}
${ if (sparse) { "@sparse" } else { "" } }
@length(min: 69)
map ${mapPrefix}Map {
key: String,
value: Recursive
}
""".asSmithyModel() to if ("${mapPrefix}Map" < "Recursive") {
"com.amazonaws.recursiveconstraintviolations#${mapPrefix}Map\$value"
} else {
"com.amazonaws.recursiveconstraintviolations#Recursive\$map"
}
private fun recursiveUnionModel(unionPrefix: String = ""): Pair<Model, String> =
"""
$baseModel
structure Recursive {
attributeValue: ${unionPrefix}AttributeValue
}
// Named `${unionPrefix}AttributeValue` in honor of DynamoDB's famous `AttributeValue`.
// https://docs.rs/aws-sdk-dynamodb/latest/aws_sdk_dynamodb/model/enum.AttributeValue.html
union ${unionPrefix}AttributeValue {
set: SetAttribute
}
@uniqueItems
list SetAttribute {
member: ${unionPrefix}AttributeValue
}
""".asSmithyModel() to
// The first loop the algorithm picks out to fix turns out to be the `list <-> union` loop:
//
// ```
// [
// ${unionPrefix}AttributeValue,
// ${unionPrefix}AttributeValue$set,
// SetAttribute,
// SetAttribute$member
// ]
// ```
//
// Upon which, after fixing it, the other loop (`structure <-> list <-> union`) already contains
// indirection, so we disregard it.
//
// This is hence a good test in that it tests that `RecursiveConstraintViolationBoxer` does not
// superfluously add more indirection than strictly necessary.
// However, it is a bad test in that if the Smithy library ever returns the recursive paths in a
// different order, the (`structure <-> list <-> union`) loop might be fixed first, and this test might
// start to fail! So watch out for that. Nonetheless, `RecursiveShapeBoxer` calls out:
//
// This function MUST be deterministic (always choose the same shapes to `Box`). If it is not, that is a bug.
//
// So I think it's fair to write this test under the above assumption.
if ("${unionPrefix}AttributeValue" < "SetAttribute") {
"com.amazonaws.recursiveconstraintviolations#${unionPrefix}AttributeValue\$set"
} else {
"com.amazonaws.recursiveconstraintviolations#SetAttribute\$member"
}
override fun provideArguments(context: ExtensionContext?): Stream<out Arguments> {
val listModels = listOf(false, true).flatMap { isSparse ->
listOf("", "ZZZ").map { listPrefix ->
val (model, shapeIdWithConstraintViolationRustBoxTrait) = recursiveListModel(isSparse, listPrefix)
var testName = "${ if (isSparse) "sparse" else "non-sparse" } recursive list"
if (listPrefix.isNotEmpty()) {
testName += " with shape name prefix $listPrefix"
}
TestCase(testName, model, shapeIdWithConstraintViolationRustBoxTrait)
}
}
val mapModels = listOf(false, true).flatMap { isSparse ->
listOf("", "ZZZ").map { mapPrefix ->
val (model, shapeIdWithConstraintViolationRustBoxTrait) = recursiveMapModel(isSparse, mapPrefix)
var testName = "${ if (isSparse) "sparse" else "non-sparse" } recursive map"
if (mapPrefix.isNotEmpty()) {
testName += " with shape name prefix $mapPrefix"
}
TestCase(testName, model, shapeIdWithConstraintViolationRustBoxTrait)
}
}
val unionModels = listOf("", "ZZZ").map { unionPrefix ->
val (model, shapeIdWithConstraintViolationRustBoxTrait) = recursiveUnionModel(unionPrefix)
var testName = "recursive union"
if (unionPrefix.isNotEmpty()) {
testName += " with shape name prefix $unionPrefix"
}
TestCase(testName, model, shapeIdWithConstraintViolationRustBoxTrait)
}
return listOf(listModels, mapModels, unionModels)
.flatten()
.map { Arguments.of(it) }.stream()
}
}
/**
* Ensures the models generate code that compiles.
*
* Make sure the tests in [software.amazon.smithy.rust.codegen.server.smithy.transformers.RecursiveConstraintViolationBoxerTest]
* are all passing before debugging any of these tests, since the former tests test preconditions for these.
*/
@ParameterizedTest
@ArgumentsSource(RecursiveConstraintViolationsTestProvider::class)
fun `recursive constraint violation code generation test`(testCase: TestCase) {
serverIntegrationTest(testCase.model)
}
}

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@ -123,7 +123,7 @@ class ServerInstantiatorTest {
},
])
string NamedEnum
""".asSmithyModel().let { RecursiveShapeBoxer.transform(it) }
""".asSmithyModel().let { RecursiveShapeBoxer().transform(it) }
private val codegenContext = serverTestCodegenContext(model)
private val symbolProvider = codegenContext.symbolProvider

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@ -0,0 +1,31 @@
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package software.amazon.smithy.rust.codegen.server.smithy.transformers
import io.kotest.matchers.shouldBe
import org.junit.jupiter.params.ParameterizedTest
import org.junit.jupiter.params.provider.ArgumentsSource
import software.amazon.smithy.rust.codegen.core.util.hasTrait
import software.amazon.smithy.rust.codegen.core.util.lookup
import software.amazon.smithy.rust.codegen.server.smithy.RecursiveConstraintViolationsTest
import software.amazon.smithy.rust.codegen.server.smithy.traits.ConstraintViolationRustBoxTrait
import kotlin.streams.toList
internal class RecursiveConstraintViolationBoxerTest {
@ParameterizedTest
@ArgumentsSource(RecursiveConstraintViolationsTest.RecursiveConstraintViolationsTestProvider::class)
fun `recursive constraint violation boxer test`(testCase: RecursiveConstraintViolationsTest.TestCase) {
val transformed = RecursiveConstraintViolationBoxer.transform(testCase.model)
val shapesWithConstraintViolationRustBoxTrait = transformed.shapes().filter {
it.hasTrait<ConstraintViolationRustBoxTrait>()
}.toList()
// Only the provided member shape should have the trait attached.
shapesWithConstraintViolationRustBoxTrait shouldBe
listOf(transformed.lookup(testCase.shapeIdWithConstraintViolationRustBoxTrait))
}
}