fix: correctly deserialize lists of documents (#748)

.changes/2032f172-904d-474b-b554-4d7fa04e160c.json

@@ -0,0 +1,5 @@
+{
+ "id": "2032f172-904d-474b-b554-4d7fa04e160c",
+ "type": "bugfix",
+ "description": "Fix deserialization error for shapes with lists of document types"
+}

smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/lang/KotlinTypes.kt

@@ -38,6 +38,8 @@ object KotlinTypes {
  val List: Symbol = builtInSymbol("List", "kotlin.collections")
  val Set: Symbol = builtInSymbol("Set", "kotlin.collections")
  val Map: Symbol = builtInSymbol("Map", "kotlin.collections")
+ val mutableListOf: Symbol = builtInSymbol("mutableListOf", "kotlin.collections")
+ val mutableMapOf: Symbol = builtInSymbol("mutableMapOf", "kotlin.collections")
  }
 
  object Jvm {

smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/rendering/serde/DeserializeStructGenerator.kt

@@ -6,6 +6,7 @@ package software.amazon.smithy.kotlin.codegen.rendering.serde
 
 import software.amazon.smithy.codegen.core.CodegenException
 import software.amazon.smithy.kotlin.codegen.core.*
+import software.amazon.smithy.kotlin.codegen.lang.KotlinTypes
 import software.amazon.smithy.kotlin.codegen.model.*
 import software.amazon.smithy.kotlin.codegen.rendering.protocol.ProtocolGenerator
 import software.amazon.smithy.model.shapes.*
@@ -137,15 +138,20 @@ open class DeserializeStructGenerator(
  val nestingLevel = 0
  val memberName = ctx.symbolProvider.toMemberName(memberShape)
  val descriptorName = memberShape.descriptorName()
- val mutableCollectionType = targetShape.mutableCollectionType()
  val valueCollector = deserializationResultName("builder.$memberName")
  val mutableCollectionName = nestingLevel.variableNameFor(NestedIdentifierType.MAP)
  val collectionReturnExpression = collectionReturnExpression(memberShape, mutableCollectionName)
 
  writer.write("$descriptorName.index -> $valueCollector = ")
  .indent()
  .withBlock("deserializer.#T($descriptorName) {", "}", RuntimeTypes.Serde.deserializeMap) {
- write("val $mutableCollectionName = $mutableCollectionType()")
+ write(
+ "val #L = #T<String, #T#L>()",
+ mutableCollectionName,
+ KotlinTypes.Collections.mutableMapOf,
+ ctx.symbolProvider.toSymbol(targetShape.value),
+ nullabilitySuffix(targetShape.isSparse),
+ )
  withBlock("while (hasNextEntry()) {", "}") {
  delegateMapDeserialization(memberShape, targetShape, nestingLevel, mutableCollectionName)
  }
@@ -252,7 +258,6 @@ open class DeserializeStructGenerator(
  val valueName = nestingLevel.variableNameFor(NestedIdentifierType.VALUE)
  val populateNullValuePostfix = if (isSparse) "" else "; continue"
  val descriptorName = rootMemberShape.descriptorName(nestingLevel.nestedDescriptorName())
- val mutableCollectionType = mapShape.mutableCollectionType()
  val nextNestingLevel = nestingLevel + 1
  val memberName = nextNestingLevel.variableNameFor(NestedIdentifierType.MAP)
  val collectionReturnExpression = collectionReturnExpression(rootMemberShape, memberName)
@@ -261,7 +266,13 @@ open class DeserializeStructGenerator(
  writer.withBlock("val $valueName =", "") {
  withBlock("if (nextHasValue()) {", "} else { deserializeNull()$populateNullValuePostfix }") {
  withBlock("deserializer.#T($descriptorName) {", "}", RuntimeTypes.Serde.deserializeMap) {
- write("val $memberName = $mutableCollectionType()")
+ write(
+ "val #L = #T<String, #T#L>()",
+ memberName,
+ KotlinTypes.Collections.mutableMapOf,
+ ctx.symbolProvider.toSymbol(mapShape.value),
+ nullabilitySuffix(mapShape.isSparse),
+ )
  withBlock("while (hasNextEntry()) {", "}") {
  delegateMapDeserialization(rootMemberShape, mapShape, nextNestingLevel, memberName)
  }
@@ -298,7 +309,6 @@ open class DeserializeStructGenerator(
  val valueName = nestingLevel.variableNameFor(NestedIdentifierType.VALUE)
  val populateNullValuePostfix = if (isSparse) "" else "; continue"
  val descriptorName = rootMemberShape.descriptorName(nestingLevel.nestedDescriptorName())
- val mutableCollectionType = collectionShape.mutableCollectionType()
  val nextNestingLevel = nestingLevel + 1
  val memberName = nextNestingLevel.variableNameFor(NestedIdentifierType.COLLECTION)
  val collectionReturnExpression = collectionReturnExpression(rootMemberShape, memberName)
@@ -307,7 +317,13 @@ open class DeserializeStructGenerator(
  writer.withBlock("val $valueName =", "") {
  withBlock("if (nextHasValue()) {", "} else { deserializeNull()$populateNullValuePostfix }") {
  withBlock("deserializer.#T($descriptorName) {", "}", RuntimeTypes.Serde.deserializeList) {
- write("val $memberName = $mutableCollectionType()")
+ write(
+ "val #L = #T<#T#L>()",
+ memberName,
+ KotlinTypes.Collections.mutableListOf,
+ ctx.symbolProvider.toSymbol(collectionShape.member),
+ nullabilitySuffix(collectionShape.isSparse),
+ )
  withBlock("while (hasNextElement()) {", "}") {
  delegateListDeserialization(rootMemberShape, collectionShape, nextNestingLevel, memberName)
  }
@@ -353,15 +369,20 @@ open class DeserializeStructGenerator(
  val nestingLevel = 0
  val memberName = ctx.symbolProvider.toMemberName(memberShape)
  val descriptorName = memberShape.descriptorName()
- val mutableCollectionType = targetShape.mutableCollectionType()
  val valueCollector = deserializationResultName("builder.$memberName")
  val mutableCollectionName = nestingLevel.variableNameFor(NestedIdentifierType.COLLECTION)
  val collectionReturnExpression = collectionReturnExpression(memberShape, mutableCollectionName)
 
  writer.write("$descriptorName.index -> $valueCollector = ")
  .indent()
  .withBlock("deserializer.#T($descriptorName) {", "}", RuntimeTypes.Serde.deserializeList) {
- write("val $mutableCollectionName = $mutableCollectionType()")
+ write(
+ "val #L = #T<#T#L>()",
+ mutableCollectionName,
+ KotlinTypes.Collections.mutableListOf,
+ ctx.symbolProvider.toSymbol(targetShape.member),
+ nullabilitySuffix(targetShape.isSparse),
+ )
  withBlock("while (hasNextElement()) {", "}") {
  delegateListDeserialization(memberShape, targetShape, nestingLevel, mutableCollectionName)
  }
@@ -454,11 +475,16 @@ open class DeserializeStructGenerator(
  val elementName = nestingLevel.variableNameFor(NestedIdentifierType.ELEMENT)
  val nextNestingLevel = nestingLevel + 1
  val mapName = nextNestingLevel.variableNameFor(NestedIdentifierType.MAP)
- val mutableCollectionType = mapShape.mutableCollectionType()
  val collectionReturnExpression = collectionReturnExpression(rootMemberShape, mapName)
 
  writer.withBlock("val $elementName = deserializer.#T($descriptorName) {", "}", RuntimeTypes.Serde.deserializeMap) {
- write("val $mapName = $mutableCollectionType()")
+ write(
+ "val #L = #T<String, #T#L>()",
+ mapName,
+ KotlinTypes.Collections.mutableMapOf,
+ ctx.symbolProvider.toSymbol(mapShape.value),
+ nullabilitySuffix(mapShape.isSparse),
+ )
  withBlock("while (hasNextEntry()) {", "}") {
  delegateMapDeserialization(rootMemberShape, mapShape, nextNestingLevel, mapName)
  }
@@ -487,11 +513,16 @@ open class DeserializeStructGenerator(
  val elementName = nestingLevel.variableNameFor(NestedIdentifierType.ELEMENT)
  val nextNestingLevel = nestingLevel + 1
  val listName = nextNestingLevel.variableNameFor(NestedIdentifierType.COLLECTION)
- val mutableCollectionType = elementShape.mutableCollectionType()
  val collectionReturnExpression = collectionReturnExpression(rootMemberShape, listName)
 
  writer.withBlock("val $elementName = deserializer.#T($descriptorName) {", "}", RuntimeTypes.Serde.deserializeList) {
- write("val $listName = $mutableCollectionType()")
+ write(
+ "val #L = #T<#T#L>()",
+ listName,
+ KotlinTypes.Collections.mutableListOf,
+ ctx.symbolProvider.toSymbol(elementShape.member),
+ nullabilitySuffix(elementShape.isSparse),
+ )
  withBlock("while (hasNextElement()) {", "}") {
  delegateListDeserialization(rootMemberShape, elementShape, nextNestingLevel, listName)
  }
@@ -569,12 +600,6 @@ open class DeserializeStructGenerator(
  else -> throw CodegenException("unknown deserializer for member: $shape; target: $target")
  }
  }
-
- // Return the function to generate a mutable instance of collection type of input shape.
- private fun MapShape.mutableCollectionType(): String =
- ctx.symbolProvider.toSymbol(this).getProperty(SymbolProperty.MUTABLE_COLLECTION_FUNCTION).get() as String
-
- // Return the function to generate a mutable instance of collection type of input shape.
- private fun CollectionShape.mutableCollectionType(): String =
- ctx.symbolProvider.toSymbol(this).getProperty(SymbolProperty.MUTABLE_COLLECTION_FUNCTION).get() as String
 }
+
+private fun nullabilitySuffix(isSparse: Boolean): String = if (isSparse) "?" else ""

smithy-kotlin-codegen/src/test/kotlin/software/amazon/smithy/kotlin/codegen/rendering/serde/DeserializeStructGeneratorTest.kt

@@ -118,6 +118,46 @@ class DeserializeStructGeneratorTest {
  actual.shouldContainOnlyOnceWithDiff(expected)
  }
 
+ @Test
+ fun `it deserializes a structure with a list of document values`() {
+ val model = (
+ modelPrefix + """ 
+ structure FooResponse { 
+ payload: DocumentList
+ }
+ 
+ list DocumentList {
+ member: Document
+ }
+ """
+ ).toSmithyModel()
+
+ val expected = """
+ deserializer.deserializeStruct(OBJ_DESCRIPTOR) {
+ loop@while (true) {
+ when (findNextFieldIndex()) {
+ PAYLOAD_DESCRIPTOR.index -> builder.payload =
+ deserializer.deserializeList(PAYLOAD_DESCRIPTOR) {
+ val col0 = mutableListOf<Document>()
+ while (hasNextElement()) {
+ val el0 = if (nextHasValue()) { deserializeDocument() } else { deserializeNull(); continue }
+ col0.add(el0)
+ }
+ col0
+ }
+ null -> break@loop
+ else -> skipValue()
+ }
+ }
+ }
+ """.trimIndent()
+
+ val actual = codegenDeserializerForShape(model, "com.test#Foo")
+
+ actual.shouldContainOnlyOnceWithDiff(expected)
+ actual.shouldContainOnlyOnceWithDiff("import aws.smithy.kotlin.runtime.smithy.Document")
+ }
+
  @Test
  fun `it deserializes a structure with a nested structure`() {
  val model = (