feat: Add default trait support

Sources/SmithyTestUtil/JSONComparator.swift

@@ -47,6 +47,8 @@ fileprivate func anyValuesAreEqual(_ lhs: Any?, _ rhs: Any?) -> Bool {
         return anyDictsAreEqual(lhsDict, rhsDict)
     } else if let lhsArray = lhs as? [Any], let rhsArray = rhs as? [Any] {
         return anyArraysAreEqual(lhsArray, rhsArray)
+    } else if let lhn = lhs as? NSNumber, let rhn = rhs as? NSNumber {
+        return lhn == rhn
     } else {
         return type(of: lhs) == type(of: rhs) && "\(lhs)" == "\(rhs)"
     }

smithy-swift-codegen/src/main/kotlin/software/amazon/smithy/swift/codegen/SwiftSymbolProvider.kt

@@ -13,6 +13,7 @@ import software.amazon.smithy.codegen.core.SymbolProvider
 import software.amazon.smithy.codegen.core.SymbolReference
 import software.amazon.smithy.model.Model
 import software.amazon.smithy.model.knowledge.NullableIndex
+import software.amazon.smithy.model.node.Node
 import software.amazon.smithy.model.shapes.BigDecimalShape
 import software.amazon.smithy.model.shapes.BigIntegerShape
 import software.amazon.smithy.model.shapes.BlobShape
@@ -23,6 +24,7 @@ import software.amazon.smithy.model.shapes.DocumentShape
 import software.amazon.smithy.model.shapes.DoubleShape
 import software.amazon.smithy.model.shapes.EnumShape
 import software.amazon.smithy.model.shapes.FloatShape
+import software.amazon.smithy.model.shapes.IntEnumShape
 import software.amazon.smithy.model.shapes.IntegerShape
 import software.amazon.smithy.model.shapes.ListShape
 import software.amazon.smithy.model.shapes.LongShape
@@ -39,8 +41,11 @@ import software.amazon.smithy.model.shapes.StringShape
 import software.amazon.smithy.model.shapes.StructureShape
 import software.amazon.smithy.model.shapes.TimestampShape
 import software.amazon.smithy.model.shapes.UnionShape
+import software.amazon.smithy.model.traits.ClientOptionalTrait
+import software.amazon.smithy.model.traits.DefaultTrait
 import software.amazon.smithy.model.traits.EnumTrait
 import software.amazon.smithy.model.traits.ErrorTrait
+import software.amazon.smithy.model.traits.InputTrait
 import software.amazon.smithy.model.traits.SparseTrait
 import software.amazon.smithy.model.traits.StreamingTrait
 import software.amazon.smithy.swift.codegen.customtraits.NestedTrait
@@ -49,8 +54,15 @@ import software.amazon.smithy.swift.codegen.model.SymbolProperty
 import software.amazon.smithy.swift.codegen.model.boxed
 import software.amazon.smithy.swift.codegen.model.buildSymbol
 import software.amazon.smithy.swift.codegen.model.defaultName
+import software.amazon.smithy.swift.codegen.model.defaultValue
+import software.amazon.smithy.swift.codegen.model.defaultValueClosure
+import software.amazon.smithy.swift.codegen.model.getTrait
 import software.amazon.smithy.swift.codegen.model.hasTrait
 import software.amazon.smithy.swift.codegen.model.nestedNamespaceType
+import software.amazon.smithy.swift.codegen.swiftmodules.FoundationTypes
+import software.amazon.smithy.swift.codegen.swiftmodules.SmithyReadWriteTypes
+import software.amazon.smithy.swift.codegen.swiftmodules.SmithyTimestampsTypes
+import software.amazon.smithy.swift.codegen.swiftmodules.SmithyTypes
 import software.amazon.smithy.swift.codegen.swiftmodules.SwiftTypes
 import software.amazon.smithy.swift.codegen.utils.ModelFileUtils
 import software.amazon.smithy.swift.codegen.utils.clientName
@@ -104,21 +116,21 @@ class SwiftSymbolProvider(private val model: Model, val swiftSettings: SwiftSett
         return escaper.escapeMemberName(shape.memberName.toLowerCamelCase())
     }
 
-    override fun integerShape(shape: IntegerShape): Symbol = numberShape(shape, "Int", "0")
+    override fun integerShape(shape: IntegerShape): Symbol = numberShape(shape, "Int")
 
-    override fun floatShape(shape: FloatShape): Symbol = numberShape(shape, "Float", "0.0")
+    override fun floatShape(shape: FloatShape): Symbol = numberShape(shape, "Float")
 
-    override fun longShape(shape: LongShape): Symbol = numberShape(shape, "Int", "0")
+    override fun longShape(shape: LongShape): Symbol = numberShape(shape, "Int")
 
-    override fun doubleShape(shape: DoubleShape): Symbol = numberShape(shape, "Double", "0.0")
+    override fun doubleShape(shape: DoubleShape): Symbol = numberShape(shape, "Double")
 
-    override fun byteShape(shape: ByteShape): Symbol = numberShape(shape, "Int8", "0")
+    override fun byteShape(shape: ByteShape): Symbol = numberShape(shape, "Int8")
 
-    override fun shortShape(shape: ShortShape): Symbol = numberShape(shape, "Int16", "0")
+    override fun shortShape(shape: ShortShape): Symbol = numberShape(shape, "Int16")
 
-    override fun bigIntegerShape(shape: BigIntegerShape): Symbol = numberShape(shape, "Int", defaultValue = "0")
+    override fun bigIntegerShape(shape: BigIntegerShape): Symbol = numberShape(shape, "Int")
 
-    override fun bigDecimalShape(shape: BigDecimalShape): Symbol = numberShape(shape, "Double", "0.0")
+    override fun bigDecimalShape(shape: BigDecimalShape): Symbol = numberShape(shape, "Double")
 
     override fun stringShape(shape: StringShape): Symbol {
         val enumTrait = shape.getTrait(EnumTrait::class.java)
@@ -149,7 +161,7 @@ class SwiftSymbolProvider(private val model: Model, val swiftSettings: SwiftSett
     }
 
     override fun booleanShape(shape: BooleanShape): Symbol {
-        return createSymbolBuilder(shape, "Bool", namespace = "Swift", SwiftDeclaration.STRUCT).putProperty(SymbolProperty.DEFAULT_VALUE_KEY, "false").build()
+        return createSymbolBuilder(shape, "Bool", namespace = "Swift", SwiftDeclaration.STRUCT).build()
     }
 
     override fun structureShape(shape: StructureShape): Symbol {
@@ -205,7 +217,7 @@ class SwiftSymbolProvider(private val model: Model, val swiftSettings: SwiftSett
                 .putProperty(SymbolProperty.NESTED_SYMBOL, symbol)
                 .build()
         }
-        return symbol
+        return handleDefaultValue(shape, symbol.toBuilder()).build()
     }
 
     override fun timestampShape(shape: TimestampShape): Symbol {
@@ -243,25 +255,30 @@ class SwiftSymbolProvider(private val model: Model, val swiftSettings: SwiftSett
             .build()
     }
 
-    private fun numberShape(shape: Shape?, typeName: String, defaultValue: String = "0"): Symbol {
-        if (shape != null && shape.isIntEnumShape()) {
+    private fun numberShape(shape: Shape, typeName: String): Symbol {
+        if (shape.isIntEnumShape()) {
             return createEnumSymbol(shape)
         }
-        return createSymbolBuilder(shape, typeName, "Swift", SwiftDeclaration.STRUCT).putProperty(SymbolProperty.DEFAULT_VALUE_KEY, defaultValue).build()
+        return createSymbolBuilder(shape, typeName, "Swift", SwiftDeclaration.STRUCT).build()
     }
 
     /**
      * Creates a symbol builder for the shape with the given type name in the root namespace.
      */
-    private fun createSymbolBuilder(shape: Shape?, typeName: String, declaration: SwiftDeclaration, boxed: Boolean = false): Symbol.Builder {
+    private fun createSymbolBuilder(
+        shape: Shape,
+        typeName: String,
+        declaration: SwiftDeclaration,
+        boxed: Boolean = false
+    ): Symbol.Builder {
         val builder = Symbol.builder()
             .putProperty("shape", shape)
             .putProperty("decl", declaration.keyword)
             .name(typeName)
         if (boxed) {
             builder.boxed()
         }
-        return builder
+        return handleDefaultValue(shape, builder)
     }
 
     /**
@@ -270,7 +287,7 @@ class SwiftSymbolProvider(private val model: Model, val swiftSettings: SwiftSett
      * the namespace (and ultimately the package name) to `foo.bar` for the symbol.
      */
     private fun createSymbolBuilder(
-        shape: Shape?,
+        shape: Shape,
         typeName: String,
         namespace: String,
         declaration: SwiftDeclaration,
@@ -284,6 +301,117 @@ class SwiftSymbolProvider(private val model: Model, val swiftSettings: SwiftSett
         return ModelFileUtils.filename(swiftSettings, name)
     }
 
+    /**
+     * Resolve default value for a given shape and save it as a property in symbol builder if needed.
+     *
+     * The default trait can be applied to list shape, map shape, and all simple types as per Smithy spec.
+     * Both the member shape and the target shape may have the default trait.
+     *
+     * There exist default value restrictions for the following shapes:
+     *  - enum: can be set to any valid string value of the enum.
+     *  - intEnum: can be set to any valid integer value of the enum.
+     *  - document: can be set to null, true, false, string, numbers, an empty list, or an empty map.
+     *  - list: can only be set to an empty list.
+     *  - map: can only be set to an empty map.
+     */
+    private fun handleDefaultValue(shape: Shape, builder: Symbol.Builder): Symbol.Builder {
+        // Skip if the current shape is a member shape with @clientOptional trait
+        if (shape.hasTrait<ClientOptionalTrait>()) return builder
+        // Skip if the current shape doesn't have default trait. Otherwise, get the default value as literal string
+        val defaultValueLiteral = shape.getTrait<DefaultTrait>()?.toNode()?.toString() ?: return builder
+        // If default value is "null", it is explicit notation for no default value. Return unmodified builder.
+        if (defaultValueLiteral == "null") return builder
+
+        // The current shape may be a member shape or a root level shape.
+        val targetShape = when (shape) {
+            is MemberShape -> {
+                // If containing shape is an input shape, return unmodified builder.
+                if (model.expectShape(shape.container).hasTrait<InputTrait>()) return builder
+                model.expectShape(shape.target)
+            }
+            else -> shape
+        }
+        val node = shape.getTrait<DefaultTrait>()!!.toNode()
+
+        return when (targetShape) {
+            is ListShape -> builder.defaultValue("[]")
+            is EnumShape -> builder.defaultValue(".${swiftEnumCaseName(null, defaultValueLiteral)}")
+            is IntEnumShape -> {
+                // Get the corresponding enum member name (enum case name) for the int value from default trait
+                val enumMemberName = targetShape.enumValues.entries.firstOrNull {
+                    it.value == defaultValueLiteral.toInt()
+                }!!.key
+                builder.defaultValue(".${swiftEnumCaseName(enumMemberName, defaultValueLiteral)}")
+            }
+            is StringShape -> builder.defaultValue("\"$defaultValueLiteral\"")
+            is MapShape -> builder.defaultValue("[:]")
+            is BlobShape -> handleBlobDefaultValue(defaultValueLiteral, targetShape, builder)
+            is DocumentShape -> {
+                handleDocumentDefaultValue(defaultValueLiteral, node, builder)
+            }
+            is TimestampShape -> handleTimestampDefaultValue(defaultValueLiteral, node, builder)
+            is FloatShape, is DoubleShape -> {
+                val decimal = ".0".takeIf { !defaultValueLiteral.contains(".") } ?: ""
+                builder.defaultValue(defaultValueLiteral + decimal)
+            }
+            // For: boolean, byte, short, integer, long, bigInteger, bigDecimal,
+            //      just take the literal string value from the trait.
+            else -> builder.defaultValue(defaultValueLiteral)
+        }
+    }
+
+    // Document: default value can be set to null, true, false, string, numbers, an empty list, or an empty map.
+    private fun handleDocumentDefaultValue(literal: String, node: Node, builder: Symbol.Builder): Symbol.Builder {
+        var formatString = when {
+            node.isObjectNode -> "\$N.object([:])"
+            node.isArrayNode -> "\$N.array([])"
+            node.isBooleanNode -> "\$N.boolean($literal)"
+            node.isStringNode -> "\$N.string(\"$literal\")"
+            node.isNumberNode -> "\$N.number($literal)"
+            else -> return builder // no-op
+        }
+        return builder.defaultValueClosure { writer ->
+            writer.format(formatString, SmithyReadWriteTypes.Document)
+        }
+    }
+
+    private fun handleBlobDefaultValue(literal: String, shape: Shape, builder: Symbol.Builder): Symbol.Builder {
+        return builder.defaultValueClosure(
+            if (shape.hasTrait<StreamingTrait>()) {
+                { writer ->
+                    writer.format(
+                        "\$N.data(\$N(\"$literal\".utf8))",
+                        SmithyTypes.ByteStream,
+                        FoundationTypes.Data
+                    )
+                }
+            } else {
+                { writer ->
+                    writer.format("\$N(\"$literal\".utf8)", FoundationTypes.Data)
+                }
+            }
+        )
+    }
+
+    private fun handleTimestampDefaultValue(literal: String, node: Node, builder: Symbol.Builder): Symbol.Builder {
+        // Smithy validates that default value given to timestamp shape must either be a
+        // number (for epoch-seconds) or a date-time string compliant with RFC3339.
+        return builder.defaultValueClosure(
+            if (node.isNumberNode) {
+                { writer ->
+                    writer.format("\$N(timeIntervalSince1970: $literal)", FoundationTypes.Date)
+                }
+            } else {
+                { writer ->
+                    writer.format(
+                        "\$N(format: .dateTime).date(from: \"$literal\")",
+                        SmithyTimestampsTypes.TimestampFormatter
+                    )
+                }
+            }
+        )
+    }
+
     /**
      * Add all the [members] as references needed to declare the given symbol being built.
      */

smithy-swift-codegen/src/main/kotlin/software/amazon/smithy/swift/codegen/SwiftWriter.kt

@@ -21,7 +21,9 @@ import software.amazon.smithy.swift.cod.DocumentationConverter
 import software.amazon.smithy.swift.codegen.integration.SectionId
 import software.amazon.smithy.swift.codegen.integration.SectionWriter
 import software.amazon.smithy.swift.codegen.integration.SwiftIntegration
+import software.amazon.smithy.swift.codegen.model.SymbolProperty
 import software.amazon.smithy.swift.codegen.model.defaultValue
+import software.amazon.smithy.swift.codegen.model.defaultValueFromClosure
 import software.amazon.smithy.swift.codegen.model.isBoxed
 import software.amazon.smithy.swift.codegen.model.isBuiltIn
 import software.amazon.smithy.swift.codegen.model.isGeneric
@@ -190,7 +192,7 @@ class SwiftWriter(
                     }
 
                     if (shouldSetDefault) {
-                        type.defaultValue()?.let {
+                        getDefaultValue(type)?.let {
                             formatted += " = $it"
                         }
                     }
@@ -200,6 +202,14 @@ class SwiftWriter(
                 else -> throw CodegenException("Invalid type provided for \$T. Expected a Symbol, but found `$type`")
             }
         }
+
+        private fun getDefaultValue(symbol: Symbol): String? {
+            return if (symbol.properties.containsKey(SymbolProperty.DEFAULT_VALUE_CLOSURE_KEY)) {
+                symbol.defaultValueFromClosure(writer)
+            } else {
+                symbol.defaultValue()
+            }
+        }
     }
 
     /**

smithy-swift-codegen/src/main/kotlin/software/amazon/smithy/swift/codegen/Utils.kt

@@ -19,7 +19,7 @@ fun String.removeSurroundingBackticks() = removeSurrounding("`", "`")
  */
 fun swiftEnumCaseName(name: String?, value: String, shouldBeEscaped: Boolean = true): String {
     val resolvedName = name ?: value
-    var enumCaseName = CaseUtils.toCamelCase(resolvedName.replace(Regex("[^a-zA-Z0-9_ ]"), ""))
+    var enumCaseName = CaseUtils.toCamelCase(resolvedName.replace(Regex("[^a-zA-Z0-9_ -]"), ""))
     if (!SwiftSymbolProvider.isValidSwiftIdentifier(enumCaseName)) {
         enumCaseName = "_$enumCaseName"
     }