fix: empty* comparison (#1102)

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

@@ -61,7 +61,6 @@ class DefaultEndpointProviderTestGenerator(
     fun render() {
         writer.addImport("*", namespace = "kotlin.test")
         writer.withBlock("public class #L {", "}", CLASS_NAME) {
-            writer.write("")
             writer.withBlock(
                 "private fun expectEqualEndpoints(expected: #1T, actual: #1T) {",
                 "}",
@@ -79,19 +78,15 @@ class DefaultEndpointProviderTestGenerator(
                         RuntimeTypes.Core.Collections.toMutableAttributes,
                     )
                     writer.write(
-                        "if (actual.attributes.contains(#1T)) newActualAttributes.remove(#1T)",
+                        "newActualAttributes.remove(#T)",
                         RuntimeTypes.Core.BusinessMetrics.ServiceEndpointOverride,
                     )
                     writer.write(
-                        "if (actual.attributes.contains(#1T)) newActualAttributes.remove(#1T)",
+                        "newActualAttributes.remove(#T)",
                         RuntimeTypes.Core.BusinessMetrics.AccountIdBasedEndpointAccountId,
                     )
                     writer.write(
-                        "val newActualAttributesOrEmpty = if (newActualAttributes.isEmpty) #T() else newActualAttributes",
-                        RuntimeTypes.Core.Collections.emptyAttributes,
-                    )
-                    writer.write(
-                        "val newActual = #T(actual.uri, actual.headers, newActualAttributesOrEmpty)",
+                        "val newActual = #T(actual.uri, actual.headers, newActualAttributes)",
                         RuntimeTypes.SmithyClient.Endpoints.Endpoint,
                     )
                     writer.write("assertEquals(expected, newActual)")

runtime/protocol/http/api/http.api

@@ -52,6 +52,7 @@ public final class aws/smithy/kotlin/runtime/http/HeadersBuilder : aws/smithy/ko
 
 public abstract class aws/smithy/kotlin/runtime/http/HttpBody {
 	public static final field Companion Laws/smithy/kotlin/runtime/http/HttpBody$Companion;
+	public fun equals (Ljava/lang/Object;)Z
 	public fun getContentLength ()Ljava/lang/Long;
 	public fun isDuplex ()Z
 	public fun isOneShot ()Z
@@ -74,6 +75,7 @@ public final class aws/smithy/kotlin/runtime/http/HttpBody$Companion {
 
 public final class aws/smithy/kotlin/runtime/http/HttpBody$Empty : aws/smithy/kotlin/runtime/http/HttpBody {
 	public static final field INSTANCE Laws/smithy/kotlin/runtime/http/HttpBody$Empty;
+	public fun equals (Ljava/lang/Object;)Z
 	public fun getContentLength ()Ljava/lang/Long;
 	public final fun isOneShot ()Z
 }

runtime/protocol/http/common/src/aws/smithy/kotlin/runtime/http/DeferredHeaders.kt

@@ -35,6 +35,7 @@ private object EmptyDeferredHeaders : DeferredHeaders {
     override fun entries(): Set<Map.Entry<String, List<Deferred<String>>>> = emptySet()
     override fun contains(name: String): Boolean = false
     override fun isEmpty(): Boolean = true
+    override fun equals(other: Any?): Boolean = other is DeferredHeaders && other.isEmpty()
 }
 
 /**

runtime/protocol/http/common/src/aws/smithy/kotlin/runtime/http/Headers.kt

@@ -32,6 +32,7 @@ private object EmptyHeaders : Headers {
     override fun entries(): Set<Map.Entry<String, List<String>>> = emptySet()
     override fun contains(name: String): Boolean = false
     override fun isEmpty(): Boolean = true
+    override fun equals(other: Any?): Boolean = other is Headers && other.isEmpty()
 }
 
 /**

runtime/protocol/http/common/src/aws/smithy/kotlin/runtime/http/HttpBody.kt

@@ -35,12 +35,19 @@ public sealed class HttpBody {
      */
     public open val isDuplex: Boolean = false
 
+    override fun equals(other: Any?): Boolean =
+        other is HttpBody &&
+            other.contentLength == contentLength &&
+            other.isOneShot == isOneShot &&
+            other.isDuplex == isDuplex
+
     /**
      * Variant of a [HttpBody] without a payload
      */
     public object Empty : HttpBody() {
         final override val isOneShot: Boolean = false
         override val contentLength: Long = 0
+        override fun equals(other: Any?): Boolean = other is HttpBody && other.contentLength == contentLength
     }
 
     /**

runtime/protocol/http/common/test/aws/smithy/kotlin/runtime/http/DeferredHeadersTest.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package aws.smithy.kotlin.runtime.http
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class DeferredHeadersTest {
+    @Test
+    fun testEmptyEquals() {
+        val explicitlyEmpty = DeferredHeaders.Empty
+        val implicitlyEmpty = DeferredHeadersBuilder().build()
+
+        assertEquals(implicitlyEmpty, explicitlyEmpty)
+        assertEquals(explicitlyEmpty, implicitlyEmpty)
+
+        assertEquals(explicitlyEmpty, explicitlyEmpty)
+        assertEquals(implicitlyEmpty, implicitlyEmpty)
+    }
+}

runtime/protocol/http/common/test/aws/smithy/kotlin/runtime/http/HeadersTest.kt

@@ -55,4 +55,16 @@ class HeadersTest {
         assertEquals(firstExpected.entries, first.entries())
         assertEquals(secondExpected.entries, second.entries())
     }
+
+    @Test
+    fun testEmptyEquals() {
+        val explicitlyEmpty = Headers.Empty
+        val implicitlyEmpty = HeadersBuilder().build()
+
+        assertEquals(implicitlyEmpty, explicitlyEmpty)
+        assertEquals(explicitlyEmpty, implicitlyEmpty)
+
+        assertEquals(explicitlyEmpty, explicitlyEmpty)
+        assertEquals(implicitlyEmpty, implicitlyEmpty)
+    }
 }

runtime/protocol/http/common/test/aws/smithy/kotlin/runtime/http/HttpBodyTest.kt

@@ -79,4 +79,16 @@ class HttpBodyTest {
 
         assertEquals(expected, body.readAll()!!.decodeToString())
     }
+
+    @Test
+    fun testEmptyEquals() {
+        val explicitlyEmpty = HttpBody.Empty
+        val implicitlyEmpty = HttpBody.fromBytes(byteArrayOf())
+
+        assertEquals(implicitlyEmpty, explicitlyEmpty)
+        assertEquals(explicitlyEmpty, implicitlyEmpty)
+
+        assertEquals(implicitlyEmpty, implicitlyEmpty)
+        assertEquals(explicitlyEmpty, explicitlyEmpty)
+    }
 }

runtime/runtime-core/common/src/aws/smithy/kotlin/runtime/collections/Attributes.kt

@@ -172,6 +172,7 @@ private object EmptyAttributes : Attributes {
     override val keys: Set<AttributeKey<*>> = emptySet()
     override fun contains(key: AttributeKey<*>): Boolean = false
     override fun <T : Any> getOrNull(key: AttributeKey<T>): T? = null
+    override fun equals(other: Any?): Boolean = other is Attributes && other.isEmpty
 }
 
 /**

runtime/runtime-core/common/test/aws/smithy/kotlin/runtime/collections/AttributesTest.kt

@@ -125,4 +125,16 @@ class AttributesTest {
         assertEquals("foo", attrs[attr1])
         assertEquals(57, attrs[attr2])
     }
+
+    @Test
+    fun testEmptyEquals() {
+        val explicitlyEmpty = emptyAttributes()
+        val implicitlyEmpty = AttributesBuilder().attributes
+
+        assertEquals(implicitlyEmpty, explicitlyEmpty)
+        assertEquals(explicitlyEmpty, implicitlyEmpty)
+
+        assertEquals(explicitlyEmpty, explicitlyEmpty)
+        assertEquals(implicitlyEmpty, implicitlyEmpty)
+    }
 }