Updates xml error unmarshalling to look at all request id keys when p…

.changes/next-release/bugfix-AWSSDKforJavav2-a6e2ed8.json

@@ -0,0 +1,6 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "contributor": "", 
+    "type": "bugfix", 
+    "description": "Fixes a bug in XML error unmarshalling where error responses with empty body won't populate the requestId field. Affects Amazon S3 API calls such as Head object"
+}

core/protocols/aws-query-protocol/src/main/java/software/amazon/awssdk/protocols/query/internal/unmarshall/AwsXmlErrorUnmarshaller.java

@@ -27,6 +27,7 @@
 import software.amazon.awssdk.awscore.exception.AwsServiceException;
 import software.amazon.awssdk.core.SdkBytes;
 import software.amazon.awssdk.core.SdkPojo;
+import software.amazon.awssdk.core.http.HttpResponseHandler;
 import software.amazon.awssdk.core.interceptor.ExecutionAttributes;
 import software.amazon.awssdk.core.interceptor.SdkExecutionAttribute;
 import software.amazon.awssdk.http.SdkHttpFullResponse;
@@ -39,7 +40,6 @@
  */
 @SdkInternalApi
 public final class AwsXmlErrorUnmarshaller {
-    private static final String X_AMZN_REQUEST_ID_HEADER = "x-amzn-RequestId";
     private static final String X_AMZ_ID_2_HEADER = "x-amz-id-2";
 
     private final List<ExceptionMetadata> exceptions;
@@ -175,7 +175,16 @@ private String getRequestId(SdkHttpFullResponse response, XmlElement document) {
                                        .orElse(document.getElementByName("RequestID"));
         return requestId != null ?
                requestId.textContent() :
-               response.firstMatchingHeader(X_AMZN_REQUEST_ID_HEADER).orElse(null);
+               matchRequestIdHeaders(response);
+    }
+
+    private String matchRequestIdHeaders(SdkHttpFullResponse response) {
+        return HttpResponseHandler.X_AMZN_REQUEST_ID_HEADERS.stream()
+                                                            .map(h -> response.firstMatchingHeader(h))
+                                                            .filter(Optional::isPresent)
+                                                            .map(Optional::get)
+                                                            .findFirst()
+                                                            .orElse(null);
     }
 
     /**

test/protocol-tests/src/test/java/software/amazon/awssdk/protocol/tests/exception/QueryExceptionTests.java

@@ -286,6 +286,19 @@ public void requestIdAndExtendedRequestIdInHeader_IsSetOnException() {
         }
     }
 
+    @Test
+    public void alternateRequestIdInHeader_IsSetOnException() {
+        stubFor(post(urlEqualTo(PATH)).willReturn(
+            aResponse()
+                .withStatus(404)
+                .withHeader("x-amz-request-id", "1234")));
+        try {
+            client.allTypes();
+        } catch (ProtocolQueryException e) {
+            assertThat(e.requestId()).isEqualTo("1234");
+        }
+    }
+
     private void callAllTypes() {
         client.allTypes(AllTypesRequest.builder().build());
     }

test/protocol-tests/src/test/java/software/amazon/awssdk/protocol/tests/exception/RestXmlExceptionTests.java

@@ -216,6 +216,19 @@ public void illegalArgumentException_emptyPathParam() {
                                      IllegalArgumentException.class);
     }
 
+    @Test
+    public void alternateRequestIdInHeader_IsSetOnException() {
+        stubFor(post(urlEqualTo(ALL_TYPES_PATH)).willReturn(
+            aResponse()
+                .withStatus(404)
+                .withHeader("x-amz-request-id", "1234")));
+        try {
+            client.allTypes();
+        } catch (ProtocolRestXmlException e) {
+            assertThat(e.requestId()).isEqualTo("1234");
+        }
+    }
+
     private void callAllTypes() {
         client.allTypes(AllTypesRequest.builder().build());
     }