From 04e5691bbab7e7d8109010a1287fe25783d6e1c1 Mon Sep 17 00:00:00 2001
From: Garrett Beatty <gcbeatty@amazon.com>
Date: Thu, 23 Oct 2025 13:32:12 -0400
Subject: [PATCH] Add ContentLanguage to header collection of
 GetObjectResponse.

stack-info: PR: https://github.com/aws/aws-sdk-net/pull/4074, branch: GarrettBeatty/stacked/7
---
 .../c49077d9-90b3-437f-b316-6d8d8833ae72.json | 11 +++++
 .../GetObjectResponseUnmarshaller.cs          |  1 +
 .../S3/IntegrationTests/GetObjectTests.cs     | 45 +++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 generator/.DevConfigs/c49077d9-90b3-437f-b316-6d8d8833ae72.json

diff --git a/generator/.DevConfigs/c49077d9-90b3-437f-b316-6d8d8833ae72.json b/generator/.DevConfigs/c49077d9-90b3-437f-b316-6d8d8833ae72.json
new file mode 100644
index 000000000000..ee368d5cf126
--- /dev/null
+++ b/generator/.DevConfigs/c49077d9-90b3-437f-b316-6d8d8833ae72.json
@@ -0,0 +1,11 @@
+{
+  "services": [
+    {
+      "serviceName": "S3",
+      "type": "patch",
+      "changeLogMessages": [
+        "Add ContentLanguage to header collection of GetObjectResponse."
+      ]
+    }
+  ]
+}
diff --git a/sdk/src/Services/S3/Custom/Model/Internal/MarshallTransformations/GetObjectResponseUnmarshaller.cs b/sdk/src/Services/S3/Custom/Model/Internal/MarshallTransformations/GetObjectResponseUnmarshaller.cs
index 410f93fd4342..171aebac022e 100644
--- a/sdk/src/Services/S3/Custom/Model/Internal/MarshallTransformations/GetObjectResponseUnmarshaller.cs
+++ b/sdk/src/Services/S3/Custom/Model/Internal/MarshallTransformations/GetObjectResponseUnmarshaller.cs
@@ -87,6 +87,7 @@ private static void UnmarshallResult(XmlUnmarshallerContext context,GetObjectRes
                 response.Headers.ContentEncoding = S3Transforms.ToString(responseData.GetHeaderValue("Content-Encoding"));
             if (responseData.IsHeaderPresent("Content-Language"))
                 response.ContentLanguage = S3Transforms.ToString(responseData.GetHeaderValue("Content-Language"));
+                response.Headers.ContentLanguage = S3Transforms.ToString(responseData.GetHeaderValue("Content-Language"));
             if (responseData.IsHeaderPresent("Content-Length"))
                 response.Headers.ContentLength = long.Parse(responseData.GetHeaderValue("Content-Length"), CultureInfo.InvariantCulture);
             if (responseData.IsHeaderPresent("x-amz-object-lock-legal-hold"))
diff --git a/sdk/test/Services/S3/IntegrationTests/GetObjectTests.cs b/sdk/test/Services/S3/IntegrationTests/GetObjectTests.cs
index 6cba8fc6b989..f4c8c103e126 100644
--- a/sdk/test/Services/S3/IntegrationTests/GetObjectTests.cs
+++ b/sdk/test/Services/S3/IntegrationTests/GetObjectTests.cs
@@ -246,5 +246,50 @@ public void TestContentLanguageResponseHeaderOverride()
                     "Original ContentLanguage should still be stored when no override is specified");
             }
         }
+
+        [TestMethod]
+        [TestCategory("S3")]
+        public void TestContentLanguageHeadersCollection()
+        {
+            var key = "TestContentLanguageHeadersCollection";
+            var expectedLanguage = "de-DE";
+
+            // Put object with Content-Language header
+            var putRequest = new PutObjectRequest
+            {
+                BucketName = bucketName,
+                Key = key,
+                ContentBody = "Test content for Content-Language headers collection"
+            };
+            putRequest.Headers["Content-Language"] = expectedLanguage;
+
+            Client.PutObject(putRequest);
+
+            // Get object and verify both ContentLanguage properties are set
+            var response = Client.GetObject(new GetObjectRequest
+            {
+                BucketName = bucketName,
+                Key = key
+            });
+
+            using (response)
+            {
+                // Verify the direct ContentLanguage property
+                Assert.IsNotNull(response.ContentLanguage, 
+                    "ContentLanguage property should not be null");
+                Assert.AreEqual(expectedLanguage, response.ContentLanguage,
+                    "ContentLanguage property should match the value set during PutObject");
+
+                // Verify the Headers.ContentLanguage property
+                Assert.IsNotNull(response.Headers.ContentLanguage, 
+                    "Headers.ContentLanguage property should not be null");
+                Assert.AreEqual(expectedLanguage, response.Headers.ContentLanguage,
+                    "Headers.ContentLanguage property should match the value set during PutObject");
+
+                // Verify both properties have the same value
+                Assert.AreEqual(response.ContentLanguage, response.Headers.ContentLanguage,
+                    "ContentLanguage and Headers.ContentLanguage should have the same value");
+            }
+        }
     }
 }