Fixed an issue in sync clients where empty response payloads could cause a null pointer exception. (#3371)

Before this change, we passed null to response transformers when the HTTP client returned empty. Our built-in response transformers expected non-null, so this would fail. This change passes an empty body to response transformers, instead.

Author: millems

.changes/next-release/bugfix-AWSSDKforJavav2-a18a347.json

@@ -0,0 +1,6 @@
+{
+    "type": "bugfix",
+    "category": "AWS SDK for Java v2",
+    "contributor": "",
+    "description": "Fixed an issue in sync clients where empty response payloads could cause a null pointer exception."
+}

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/handler/BaseSyncClientHandler.java

@@ -203,7 +203,7 @@ private HttpResponseHandlerAdapter(HttpResponseHandler<OutputT> httpResponseHand
         @Override
         public ReturnT handle(SdkHttpFullResponse response, ExecutionAttributes executionAttributes) throws Exception {
             OutputT resp = httpResponseHandler.handle(response, executionAttributes);
-            return transformResponse(resp, response.content().orElse(null));
+            return transformResponse(resp, response.content().orElseGet(AbortableInputStream::createEmpty));
         }
 
         @Override

core/sdk-core/src/main/java/software/amazon/awssdk/core/sync/ResponseTransformer.java

@@ -172,7 +172,7 @@ static <ResponseT> ResponseTransformer<ResponseT, ResponseBytes<ResponseT>> toBy
         return (response, inputStream) -> {
             try {
                 InterruptMonitor.checkInterrupted();
-                return ResponseBytes.fromByteArray(response, IoUtils.toByteArray(inputStream));
+                return ResponseBytes.fromByteArrayUnsafe(response, IoUtils.toByteArray(inputStream));
             } catch (IOException e) {
                 throw RetryableException.builder().message("Failed to read response.").cause(e).build();
             }

http-client-spi/src/main/java/software/amazon/awssdk/http/AbortableInputStream.java

@@ -17,6 +17,7 @@
 
 import static software.amazon.awssdk.utils.Validate.paramNotNull;
 
+import java.io.ByteArrayInputStream;
 import java.io.FilterInputStream;
 import java.io.InputStream;
 import software.amazon.awssdk.annotations.SdkProtectedApi;
@@ -61,6 +62,10 @@ public static AbortableInputStream create(InputStream delegate) {
         return new AbortableInputStream(delegate, () -> { });
     }
 
+    public static AbortableInputStream createEmpty() {
+        return create(new ByteArrayInputStream(new byte[0]));
+    }
+
     @Override
     public void abort() {
         abortable.abort();

http-clients/url-connection-client/src/it/java/software/amazon/awssdk/http/urlconnection/EmptyFileS3IntegrationTest.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.http.urlconnection;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static software.amazon.awssdk.testutils.service.S3BucketUtils.temporaryBucketName;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import software.amazon.awssdk.core.sync.RequestBody;
+import software.amazon.awssdk.services.s3.S3Client;
+
+public class EmptyFileS3IntegrationTest extends UrlHttpConnectionS3IntegrationTestBase {
+    private static final String BUCKET = temporaryBucketName(EmptyFileS3IntegrationTest.class);
+
+    @BeforeClass
+    public static void setup() {
+        createBucket(BUCKET);
+    }
+
+    @AfterClass
+    public static void cleanup() {
+        deleteBucketAndAllContents(BUCKET);
+    }
+
+    @Test
+    public void s3EmptyFileGetAsBytesWorksWithoutChecksumValidationEnabled() {
+        try (S3Client s3 = s3ClientBuilder().serviceConfiguration(c -> c.checksumValidationEnabled(false))
+                                            .build()) {
+            s3.putObject(r -> r.bucket(BUCKET).key("x"), RequestBody.empty());
+            assertThat(s3.getObjectAsBytes(r -> r.bucket(BUCKET).key("x")).asUtf8String()).isEmpty();
+        }
+    }
+
+    @Test
+    public void s3EmptyFileContentLengthIsCorrectWithoutChecksumValidationEnabled() {
+        try (S3Client s3 = s3ClientBuilder().serviceConfiguration(c -> c.checksumValidationEnabled(false))
+                                            .build()) {
+            s3.putObject(r -> r.bucket(BUCKET).key("x"), RequestBody.empty());
+            assertThat(s3.getObject(r -> r.bucket(BUCKET).key("x")).response().contentLength()).isEqualTo(0);
+        }
+    }
+}

http-clients/url-connection-client/src/it/java/software/amazon/awssdk/http/urlconnection/UrlHttpConnectionS3IntegrationTestBase.java

@@ -15,32 +15,19 @@
 
 package software.amazon.awssdk.http.urlconnection;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
 import java.util.Iterator;
 import java.util.List;
 import org.junit.BeforeClass;
-import software.amazon.awssdk.core.ClientType;
-import software.amazon.awssdk.core.interceptor.Context;
-import software.amazon.awssdk.core.interceptor.ExecutionAttributes;
-import software.amazon.awssdk.core.interceptor.ExecutionInterceptor;
-import software.amazon.awssdk.http.apache.ApacheHttpClient;
 import software.amazon.awssdk.regions.Region;
-import software.amazon.awssdk.services.s3.S3AsyncClient;
-import software.amazon.awssdk.services.s3.S3AsyncClientBuilder;
 import software.amazon.awssdk.services.s3.S3Client;
 import software.amazon.awssdk.services.s3.S3ClientBuilder;
-import software.amazon.awssdk.services.s3.model.BucketLocationConstraint;
-import software.amazon.awssdk.services.s3.model.CreateBucketConfiguration;
-import software.amazon.awssdk.services.s3.model.CreateBucketRequest;
 import software.amazon.awssdk.services.s3.model.DeleteBucketRequest;
 import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
 import software.amazon.awssdk.services.s3.model.ListObjectVersionsRequest;
 import software.amazon.awssdk.services.s3.model.ListObjectVersionsResponse;
 import software.amazon.awssdk.services.s3.model.ListObjectsRequest;
 import software.amazon.awssdk.services.s3.model.ListObjectsResponse;
 import software.amazon.awssdk.services.s3.model.NoSuchBucketException;
-import software.amazon.awssdk.services.s3.model.S3Exception;
 import software.amazon.awssdk.services.s3.model.S3Object;
 import software.amazon.awssdk.testutils.Waiter;
 import software.amazon.awssdk.testutils.service.AwsTestBase;
@@ -79,6 +66,7 @@ protected static void createBucket(String bucket) {
         Waiter.run(() -> s3.createBucket(r -> r.bucket(bucket)))
               .ignoringException(NoSuchBucketException.class)
               .orFail();
+        s3.waiter().waitUntilBucketExists(r -> r.bucket(bucket));
     }
 
     protected static void deleteBucketAndAllContents(String bucketName) {