From 6a92568b40a545c148ffca169766d006df2ab16c Mon Sep 17 00:00:00 2001
From: Russell Cohen <rcoh@amazon.com>
Date: Thu, 3 Jun 2021 15:45:39 -0400
Subject: [PATCH] fix s3 head object errors (#460)

s3 head object and head bucket can both return 404 with no body. This requires a special error handling case to avoid attempting to parse the body as XML.
---
 .../rustsdk/customize/s3/S3Decorator.kt       | 16 ++++++++++---
 aws/sdk/aws-models/s3-tests.smithy            | 23 +++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)
 create mode 100644 aws/sdk/aws-models/s3-tests.smithy

diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/customize/s3/S3Decorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/customize/s3/S3Decorator.kt
index 689e62a33..a4d0c7c8a 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/customize/s3/S3Decorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/customize/s3/S3Decorator.kt
@@ -68,10 +68,20 @@ class S3(protocolConfig: ProtocolConfig) : RestXml(protocolConfig) {
             ) {
                 rustTemplate(
                     """
-                    let base_err = #{base_errors}::parse_generic_error(response.body().as_ref())?;
-                    Ok(#{s3_errors}::parse_extended_error(base_err, &response))
+                    if response.body().is_empty() {
+                        let mut err = #{Error}::builder();
+                        if response.status().as_u16() == 404 {
+                            err.code("NotFound");
+                        }
+                        Ok(err.build())
+                    } else {
+                        let base_err = #{base_errors}::parse_generic_error(response.body().as_ref())?;
+                        Ok(#{s3_errors}::parse_extended_error(base_err, &response))
+                    }
                 """,
-                    "base_errors" to restXmlErrors, "s3_errors" to AwsRuntimeType.S3Errors
+                    "base_errors" to restXmlErrors,
+                    "s3_errors" to AwsRuntimeType.S3Errors,
+                    "Error" to RuntimeType.GenericError(runtimeConfig)
                 )
             }
         }
diff --git a/aws/sdk/aws-models/s3-tests.smithy b/aws/sdk/aws-models/s3-tests.smithy
new file mode 100644
index 000000000..3cca54df4
--- /dev/null
+++ b/aws/sdk/aws-models/s3-tests.smithy
@@ -0,0 +1,23 @@
+$version: "1.0"
+
+namespace com.amazonaws.s3
+use smithy.test#httpResponseTests
+
+apply NotFound @httpResponseTests([
+    {
+        id: "HeadObjectEmptyBody",
+        documentation: "This test case validates https://github.com/awslabs/smithy-rs/issues/456",
+        params: {
+        },
+        body: "",
+        protocol: "aws.protocols#restXml",
+        code: 404,
+        headers: {
+            "x-amz-request-id": "GRZ6BZ468DF52F2E",
+            "x-amz-id-2": "UTniwu6QmCIjVeuK2ZfeWBOnu7SqMQOS3Vac6B/K4H2ZCawYUl+nDbhGTImuyhZ5DFiojR3Kcz4=",
+            "content-type": "application/xml",
+            "date": "Thu, 03 Jun 2021 04:05:52 GMT",
+            "server": "AmazonS3"
+        }
+    }
+])
-- 
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