Update codegen to generate base exception rather than UnknownServiceErrorException

codegen/smithy-aws-kotlin-codegen/src/main/kotlin/aws/sdk/kotlin/codegen/customization/s3/S3Generator.kt

@@ -92,7 +92,7 @@ class S3Generator : RestXml() {
             }
             .dedent()
             .withBlock("} catch (ex: Exception) {", "}") {
-                withBlock("""throw #T("failed to parse response as ${ctx.protocol.name} error", ex).also {""", "}", AwsRuntimeTypes.Core.UnknownServiceErrorException) {
+                withBlock("""throw #T("Failed to parse response as '${ctx.protocol.name}' error", ex).also {""", "}", exceptionBaseSymbol) {
                     write("#T(it, wrappedResponse, null)", setS3ErrorMetadata)
                 }
             }

codegen/smithy-aws-kotlin-codegen/src/main/kotlin/aws/sdk/kotlin/codegen/protocols/core/AwsHttpBindingProtocolGenerator.kt

@@ -136,7 +136,7 @@ abstract class AwsHttpBindingProtocolGenerator : HttpBindingProtocolGenerator()
             }
             .dedent()
             .withBlock("} catch (ex: Exception) {", "}") {
-                withBlock("""throw #T("failed to parse response as ${ctx.protocol.name} error", ex).also {""", "}", AwsRuntimeTypes.Core.UnknownServiceErrorException) {
+                withBlock("""throw #T("Failed to parse response as '${ctx.protocol.name}' error", ex).also {""", "}", exceptionBaseSymbol) {
                     write("#T(it, wrappedResponse, null)", AwsRuntimeTypes.Http.setAseErrorMetadata)
                 }
             }

codegen/smithy-aws-kotlin-codegen/src/test/kotlin/aws/sdk/kotlin/codegen/protocols/core/AwsHttpBindingProtocolGeneratorTest.kt

@@ -0,0 +1,128 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+package aws.sdk.kotlin.codegen.protocols.core
+
+import software.amazon.smithy.kotlin.codegen.core.KotlinWriter
+import software.amazon.smithy.kotlin.codegen.model.expectShape
+import software.amazon.smithy.kotlin.codegen.rendering.protocol.HttpBindingResolver
+import software.amazon.smithy.kotlin.codegen.rendering.protocol.ProtocolGenerator
+import software.amazon.smithy.kotlin.codegen.test.defaultSettings
+import software.amazon.smithy.kotlin.codegen.test.newTestContext
+import software.amazon.smithy.kotlin.codegen.test.shouldContainOnlyOnceWithDiff
+import software.amazon.smithy.kotlin.codegen.test.toSmithyModel
+import software.amazon.smithy.model.Model
+import software.amazon.smithy.model.shapes.OperationShape
+import software.amazon.smithy.model.shapes.ServiceShape
+import software.amazon.smithy.model.shapes.Shape
+import software.amazon.smithy.model.shapes.ShapeId
+import software.amazon.smithy.model.traits.TimestampFormatTrait
+import kotlin.test.Test
+
+class AwsHttpBindingProtocolGeneratorTest {
+
+    @Test
+    fun `it throws base service exception on error parse failure`() {
+        val model = """
+            namespace com.test
+            use aws.protocols#restJson1
+
+            @restJson1
+            service Example {
+                version: "1.0.0",
+                operations: [GetFoo]
+            }
+
+            operation GetFoo {
+                errors: [FooError]
+            }
+
+            @error("server")
+            structure FooError {
+                payload: String
+            }
+        """.toSmithyModel()
+
+        // This is the value that produces the name of the service base exception type
+        val serviceSdkName = "SdkName"
+
+        val testCtx = model.newTestContext(
+            serviceName = "Example",
+            settings = model.defaultSettings(sdkId = serviceSdkName)
+        )
+        val writer = KotlinWriter("com.test")
+        val unit = TestableAwsHttpBindingProtocolGenerator()
+        val op = model.expectShape<OperationShape>("com.test#GetFoo")
+
+        unit.renderThrowOperationError(testCtx.generationCtx, op, writer)
+
+        val actual = writer.toString()
+        val expected = """
+            throw ${serviceSdkName}Exception("Failed to parse response as 'restJson1' error", ex).also {
+        """.trimIndent()
+
+        actual.shouldContainOnlyOnceWithDiff(expected)
+    }
+
+    // A concrete implementation of AwsHttpBindingProtocolGenerator to exercise renderThrowOperationError()
+    class TestableAwsHttpBindingProtocolGenerator : AwsHttpBindingProtocolGenerator() {
+        override fun renderDeserializeErrorDetails(
+            ctx: ProtocolGenerator.GenerationContext,
+            op: OperationShape,
+            writer: KotlinWriter
+        ) {
+            // NOP
+        }
+
+        override val defaultTimestampFormat: TimestampFormatTrait.Format
+            get() = TODO("Unneeded for test")
+
+        override fun getProtocolHttpBindingResolver(model: Model, serviceShape: ServiceShape): HttpBindingResolver {
+            TODO("Unneeded for test")
+        }
+
+        override fun renderSerializeOperationBody(
+            ctx: ProtocolGenerator.GenerationContext,
+            op: OperationShape,
+            writer: KotlinWriter
+        ) {
+            TODO("Unneeded for test")
+        }
+
+        override fun renderDeserializeOperationBody(
+            ctx: ProtocolGenerator.GenerationContext,
+            op: OperationShape,
+            writer: KotlinWriter
+        ) {
+            TODO("Unneeded for test")
+        }
+
+        override fun renderSerializeDocumentBody(
+            ctx: ProtocolGenerator.GenerationContext,
+            shape: Shape,
+            writer: KotlinWriter
+        ) {
+            TODO("Unneeded for test")
+        }
+
+        override fun renderDeserializeDocumentBody(
+            ctx: ProtocolGenerator.GenerationContext,
+            shape: Shape,
+            writer: KotlinWriter
+        ) {
+            TODO("Unneeded for test")
+        }
+
+        override fun renderDeserializeException(
+            ctx: ProtocolGenerator.GenerationContext,
+            shape: Shape,
+            writer: KotlinWriter
+        ) {
+            TODO("Unneeded for test")
+        }
+
+        override val protocol: ShapeId
+            get() = TODO("Unneeded for test")
+    }
+}