refactor XML deserialization

.changes/fb00b4ae-ffdb-4137-baa8-574848296da1.json

@@ -0,0 +1,8 @@
+{
+    "id": "fb00b4ae-ffdb-4137-baa8-574848296da1",
+    "type": "bugfix",
+    "description": "Refactor XML deserialization to handle flat collections",
+    "issues": [
+        "awslabs/aws-sdk-kotlin#1220"
+    ]
+}

build.gradle.kts

@@ -130,7 +130,8 @@ apiValidation {
             "channel-benchmarks",
             "http-benchmarks",
             "serde-benchmarks",
-            "serde-benchmarks-codegen",
+            "serde-codegen-support",
+            "serde-tests",
             "nullability-tests",
             "paginator-tests",
             "waiter-tests",

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/core/AbstractCodeWriterExt.kt

@@ -187,3 +187,7 @@ fun <T : AbstractCodeWriter<T>> T.callIf(test: Boolean, runnable: Runnable): T {
     }
     return this
 }
+
+/** Escape the [expressionStart] character to avoid problems during formatting */
+fun <T : AbstractCodeWriter<T>> T.escape(text: String): String =
+    text.replace("$expressionStart", "$expressionStart$expressionStart")

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/core/RuntimeTypes.kt

@@ -103,6 +103,7 @@ object RuntimeTypes {
             val Attributes = symbol("Attributes")
             val attributesOf = symbol("attributesOf")
             val AttributeKey = symbol("AttributeKey")
+            val createOrAppend = symbol("createOrAppend")
             val get = symbol("get")
             val mutableMultiMapOf = symbol("mutableMultiMapOf")
             val putIfAbsent = symbol("putIfAbsent")
@@ -230,6 +231,7 @@ object RuntimeTypes {
         val SerialKind = symbol("SerialKind")
         val SerializationException = symbol("SerializationException")
         val DeserializationException = symbol("DeserializationException")
+        val getOrDeserializeErr = symbol("getOrDeserializeErr")
 
         val serializeStruct = symbol("serializeStruct")
         val serializeList = symbol("serializeList")
@@ -241,6 +243,18 @@ object RuntimeTypes {
         val asSdkSerializable = symbol("asSdkSerializable")
         val field = symbol("field")
 
+        val parse = symbol("parse")
+        val parseInt = symbol("parseInt")
+        val parseShort = symbol("parseShort")
+        val parseLong = symbol("parseLong")
+        val parseFloat = symbol("parseFloat")
+        val parseDouble = symbol("parseDouble")
+        val parseByte = symbol("parseByte")
+        val parseBoolean = symbol("parseBoolean")
+        val parseTimestamp = symbol("parseTimestamp")
+        val parseBigInteger = symbol("parseBigInteger")
+        val parseBigDecimal = symbol("parseBigDecimal")
+
         object SerdeJson : RuntimeTypePackage(KotlinDependency.SERDE_JSON) {
             val JsonSerialName = symbol("JsonSerialName")
             val JsonSerializer = symbol("JsonSerializer")
@@ -260,8 +274,13 @@ object RuntimeTypes {
             val XmlMapName = symbol("XmlMapName")
             val XmlError = symbol("XmlError")
             val XmlSerializer = symbol("XmlSerializer")
-            val XmlDeserializer = symbol("XmlDeserializer")
             val XmlUnwrappedOutput = symbol("XmlUnwrappedOutput")
+
+            val XmlTagReader = symbol("XmlTagReader")
+            val xmlStreamReader = symbol("xmlStreamReader")
+            val xmlRootTagReader = symbol("xmlTagReader")
+            val data = symbol("data")
+            val tryData = symbol("tryData")
         }
 
         object SerdeFormUrl : RuntimeTypePackage(KotlinDependency.SERDE_FORM_URL) {

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

@@ -41,6 +41,7 @@ object KotlinTypes {
         val List: Symbol = stdlibSymbol("List")
         val listOf: Symbol = stdlibSymbol("listOf")
         val MutableList: Symbol = stdlibSymbol("MutableList")
+        val MutableMap: Symbol = stdlibSymbol("MutableMap")
         val Map: Symbol = stdlibSymbol("Map")
         val mutableListOf: Symbol = stdlibSymbol("mutableListOf")
         val mutableMapOf: Symbol = stdlibSymbol("mutableMapOf")

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/rendering/protocol/HttpBindingProtocolGenerator.kt

@@ -14,7 +14,7 @@ import software.amazon.smithy.kotlin.codegen.lang.toEscapedLiteral
 import software.amazon.smithy.kotlin.codegen.model.*
 import software.amazon.smithy.kotlin.codegen.rendering.serde.deserializerName
 import software.amazon.smithy.kotlin.codegen.rendering.serde.formatInstant
-import software.amazon.smithy.kotlin.codegen.rendering.serde.parseInstant
+import software.amazon.smithy.kotlin.codegen.rendering.serde.parseInstantExpr
 import software.amazon.smithy.kotlin.codegen.rendering.serde.serializerName
 import software.amazon.smithy.kotlin.codegen.utils.getOrNull
 import software.amazon.smithy.model.Model
@@ -813,14 +813,12 @@ abstract class HttpBindingProtocolGenerator : ProtocolGenerator {
                         HttpBinding.Location.HEADER,
                         defaultTimestampFormat,
                     )
-                    writer
-                        .addImport(RuntimeTypes.Core.Instant)
-                        .write(
-                            "builder.#L = response.headers[#S]?.let { #L }",
-                            memberName,
-                            headerName,
-                            parseInstant("it", tsFormat),
-                        )
+                    writer.write(
+                        "builder.#L = response.headers[#S]?.let { #L }",
+                        memberName,
+                        headerName,
+                        writer.parseInstantExpr("it", tsFormat),
+                    )
                 }
                 is ListShape -> {
                     // member > boolean, number, string, or timestamp
@@ -849,8 +847,7 @@ abstract class HttpBindingProtocolGenerator : ProtocolGenerator {
                             if (tsFormat == TimestampFormatTrait.Format.HTTP_DATE) {
                                 splitFn = "splitHttpDateHeaderListValues"
                             }
-                            writer.addImport(RuntimeTypes.Core.Instant)
-                            parseInstant("it", tsFormat)
+                            writer.parseInstantExpr("it", tsFormat)
                         }
                         is StringShape -> {
                             when {

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

@@ -605,5 +605,3 @@ open class DeserializeStructGenerator(
         }
     }
 }
-
-private fun nullabilitySuffix(isSparse: Boolean): String = if (isSparse) "?" else ""

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

@@ -9,8 +9,7 @@ import software.amazon.smithy.codegen.core.CodegenException
 import software.amazon.smithy.codegen.core.Symbol
 import software.amazon.smithy.codegen.core.SymbolReference
 import software.amazon.smithy.kotlin.codegen.KotlinSettings
-import software.amazon.smithy.kotlin.codegen.core.SymbolRenderer
-import software.amazon.smithy.kotlin.codegen.core.defaultName
+import software.amazon.smithy.kotlin.codegen.core.*
 import software.amazon.smithy.kotlin.codegen.core.mangledSuffix
 import software.amazon.smithy.kotlin.codegen.model.buildSymbol
 import software.amazon.smithy.model.Model
@@ -216,11 +215,31 @@ fun formatInstant(paramName: String, tsFmt: TimestampFormatTrait.Format, forceSt
  * @param paramName The name of the local identifier to convert to an `Instant`
  * @param tsFmt The timestamp format [paramName] is expected to be converted from
  */
-fun parseInstant(paramName: String, tsFmt: TimestampFormatTrait.Format): String = when (tsFmt) {
-    TimestampFormatTrait.Format.EPOCH_SECONDS -> "Instant.fromEpochSeconds($paramName)"
-    TimestampFormatTrait.Format.DATE_TIME -> "Instant.fromIso8601($paramName)"
-    TimestampFormatTrait.Format.HTTP_DATE -> "Instant.fromRfc5322($paramName)"
-    else -> throw CodegenException("unknown timestamp format: $tsFmt")
+fun KotlinWriter.parseInstantExpr(paramName: String, tsFmt: TimestampFormatTrait.Format): String {
+    val fn = when (tsFmt) {
+        TimestampFormatTrait.Format.EPOCH_SECONDS -> "fromEpochSeconds"
+        TimestampFormatTrait.Format.DATE_TIME -> "fromIso8601"
+        TimestampFormatTrait.Format.HTTP_DATE -> "fromRfc5322"
+        else -> throw CodegenException("unknown timestamp format: $tsFmt")
+    }
+    return format("#T.#L(#L)", RuntimeTypes.Core.Instant, fn, paramName)
+}
+
+fun TimestampFormatTrait.Format.toRuntimeEnum(): String = when (this) {
+    TimestampFormatTrait.Format.EPOCH_SECONDS -> "TimestampFormat.EPOCH_SECONDS"
+    TimestampFormatTrait.Format.DATE_TIME -> "TimestampFormat.ISO_8601"
+    TimestampFormatTrait.Format.HTTP_DATE -> "TimestampFormat.RFC_5322"
+    else -> throw CodegenException("unknown timestamp format: $this")
+}
+
+fun TimestampFormatTrait.Format.toRuntimeEnum(writer: KotlinWriter): String {
+    val enum = when (this) {
+        TimestampFormatTrait.Format.EPOCH_SECONDS -> "EPOCH_SECONDS"
+        TimestampFormatTrait.Format.DATE_TIME -> "ISO_8601"
+        TimestampFormatTrait.Format.HTTP_DATE -> "RFC_5322"
+        else -> throw CodegenException("unknown timestamp format: $this")
+    }
+    return writer.format("#T.#L", RuntimeTypes.Core.TimestampFormat, enum)
 }
 
 /**
@@ -289,3 +308,5 @@ internal fun Shape.childShape(model: Model): Shape? = when (this) {
     is MapShape -> model.expectShape(this.value.target)
     else -> null
 }
+
+internal fun nullabilitySuffix(isSparse: Boolean): String = if (isSparse) "?" else ""

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

@@ -680,10 +680,3 @@ open class SerializeStructGenerator(
         return "serialize$suffix"
     }
 }
-
-fun TimestampFormatTrait.Format.toRuntimeEnum(): String = when (this) {
-    TimestampFormatTrait.Format.EPOCH_SECONDS -> "TimestampFormat.EPOCH_SECONDS"
-    TimestampFormatTrait.Format.DATE_TIME -> "TimestampFormat.ISO_8601"
-    TimestampFormatTrait.Format.HTTP_DATE -> "TimestampFormat.RFC_5322"
-    else -> throw CodegenException("unknown timestamp format: $this")
-}