Fix smithy sdk no default client

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

@@ -44,7 +44,8 @@ class ServiceGenerator(private val ctx: RenderingContext<ServiceShape>) {
         require(ctx.shape is ServiceShape) { "ServiceShape is required for generating a service interface; was: ${ctx.shape}" }
     }
 
-    private val service: ServiceShape = requireNotNull(ctx.shape) { "ServiceShape is required to render a service client" }
+    private val service: ServiceShape =
+        requireNotNull(ctx.shape) { "ServiceShape is required to render a service client" }
     private val serviceSymbol = ctx.symbolProvider.toSymbol(service)
     private val writer = ctx.writer
 
@@ -72,7 +73,7 @@ class ServiceGenerator(private val ctx: RenderingContext<ServiceShape>) {
                     SectionServiceCompanionObject,
                     context = mapOf(SectionServiceCompanionObject.ServiceSymbol to serviceSymbol)
                 ) {
-                    renderCompanionObject()
+                    renderCompanionObject(ctx.protocolGenerator != null)
                 }
                 writer.write("")
                 renderServiceConfig()
@@ -109,16 +110,20 @@ class ServiceGenerator(private val ctx: RenderingContext<ServiceShape>) {
      *     operator fun invoke(config: Config): LambdaClient = DefaultLambdaClient(config)
      * }
      * ```
+     * @param hasProtocolGenerator true if there is a [ProtocolGenerator] set on the [RenderingContext].  This
+     * determines if the SDK will generate a default client implementation. If there is no [ProtocolGenerator], do not
+     * codegen references to the non-existent default client.
      */
-    private fun renderCompanionObject() {
+    private fun renderCompanionObject(hasProtocolGenerator: Boolean) {
         writer.withBlock("companion object {", "}") {
-            withBlock("operator fun invoke(block: Config.Builder.() -> Unit = {}): ${serviceSymbol.name} {", "}") {
-                write("val config = Config.Builder().apply(block).build()")
-                write("return Default${serviceSymbol.name}(config)")
+            this.callIf(hasProtocolGenerator) {
+                withBlock("operator fun invoke(block: Config.Builder.() -> Unit = {}): ${serviceSymbol.name} {", "}") {
+                    write("val config = Config.Builder().apply(block).build()")
+                    write("return Default${serviceSymbol.name}(config)")
+                }
+                write("")
+                write("operator fun invoke(config: Config): ${serviceSymbol.name} = Default${serviceSymbol.name}(config)")
             }
-
-            write("")
-            write("operator fun invoke(config: Config): ${serviceSymbol.name} = Default${serviceSymbol.name}(config)")
         }
     }
 

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

@@ -63,7 +63,7 @@ class ServiceGeneratorTest {
     }
 
     @Test
-    fun `it renders a companion object`() {
+    fun `it renders a companion object with default client factory if protocol generator`() {
         val expected = """
             companion object {
                 operator fun invoke(block: Config.Builder.() -> Unit = {}): TestClient {
@@ -74,6 +74,16 @@ class ServiceGeneratorTest {
                 operator fun invoke(config: Config): TestClient = DefaultTestClient(config)
             }
         """.formatForTest()
+        val testContents = generateService("service-generator-test-operations.smithy", true)
+        testContents.shouldContainOnlyOnceWithDiff(expected)
+    }
+
+    @Test
+    fun `it renders a companion object without default client factory if no protocol generator`() {
+        val expected = """
+            companion object {
+            }
+        """.formatForTest()
         commonTestContents.shouldContainOnlyOnceWithDiff(expected)
     }
 
@@ -164,14 +174,15 @@ class ServiceGeneratorTest {
     }
 
     // Produce the generated service code given model inputs.
-    private fun generateService(modelResourceName: String): String {
+    private fun generateService(modelResourceName: String, withProtocolGenerator: Boolean = false): String {
         val model = loadModelFromResource(modelResourceName)
 
         val provider: SymbolProvider = KotlinCodegenPlugin.createSymbolProvider(model)
         val writer = KotlinWriter(TestModelDefault.NAMESPACE)
         val service = model.getShape(ShapeId.from(TestModelDefault.SERVICE_SHAPE_ID)).get().asServiceShape().get()
         val settings = KotlinSettings(service.id, KotlinSettings.PackageSettings(TestModelDefault.NAMESPACE, TestModelDefault.MODEL_VERSION), sdkId = service.id.name)
-        val renderingCtx = RenderingContext(writer, service, model, provider, settings)
+        val protocolGenerator = if (withProtocolGenerator) MockHttpProtocolGenerator() else null
+        val renderingCtx = RenderingContext(writer, service, model, provider, settings, protocolGenerator)
         val generator = ServiceGenerator(renderingCtx)
 
         generator.render()