Merge smithy-rs-release-1.x.y into main (#4134)

Author: aws-sdk-rust-ci

.changelog/1747202677.md

@@ -1,4 +1,15 @@
 <!-- Do not manually edit this file. Use the `changelogger` tool. -->
+May 15th, 2025
+==============
+**New this release:**
+- :bug: (all, [smithy-rs#4132](https://github.com/smithy-lang/smithy-rs/issues/4132)) Smithy unions that contain members named "unknown" will now codegen correctly
+- (all, [smithy-rs#4105](https://github.com/smithy-lang/smithy-rs/issues/4105), @FalkWoldmann) Replace once_cell with std equivalents
+
+**Contributors**
+Thank you for your contributions! ❤
+- @FalkWoldmann ([smithy-rs#4105](https://github.com/smithy-lang/smithy-rs/issues/4105))
+
+
 May 9th, 2025
 =============
 **Breaking Changes:**

.changelog/unknown-variants.md

@@ -5,20 +5,6 @@
 {
   "smithy-rs": [],
   "aws-sdk-rust": [
-    {
-      "message": "Update spans to better align with spec.\n",
-      "meta": {
-        "bug": false,
-        "breaking": false,
-        "tada": false
-      },
-      "author": "landonxjames",
-      "references": [
-        "smithy-rs#4052"
-      ],
-      "since-commit": "7558d31f17b69bce8785ffa833c575d0b172209c",
-      "age": 5
-    },
     {
       "message": "Replace the `once_cell` crate with the `std` counterpart in AWS runtime crates.\n",
       "meta": {
@@ -31,7 +17,7 @@
         "smithy-rs#4050"
       ],
       "since-commit": "f0c92d92b680771787af8ab60995d0e1fae02611",
-      "age": 3
+      "age": 4
     },
     {
       "message": "Fix an issue where a custom `Content-Encoding` header was incorrectly overwritten by the `aws-chunked` header value.\n",
@@ -45,7 +31,7 @@
         "aws-sdk-rust#1281"
       ],
       "since-commit": "f0c92d92b680771787af8ab60995d0e1fae02611",
-      "age": 3
+      "age": 4
     },
     {
       "message": "Add support for the account-based endpoints in AWS SDKs. For more details, please refer to the [AWS SDKs and Tools Reference Guide on Account-Based Endpoints](https://docs.aws.amazon.com/sdkref/latest/guide/feature-account-endpoints.html).\n",
@@ -59,7 +45,7 @@
         "smithy-rs#3776"
       ],
       "since-commit": "f0c92d92b680771787af8ab60995d0e1fae02611",
-      "age": 3
+      "age": 4
     },
     {
       "message": "Fix service specific endpoint url keys\n",
@@ -73,7 +59,7 @@
         "aws-sdk-rust#1252"
       ],
       "since-commit": "f0c92d92b680771787af8ab60995d0e1fae02611",
-      "age": 3
+      "age": 4
     },
     {
       "message": "Fix a bug where fields that were initially annotated with the `required` trait and later updated to use the `addedDefault` trait were not serialized when their values matched the default, even when the values were explicitly set. With this fix, fields with `addedDefault` are now always serialized.\n",
@@ -87,7 +73,7 @@
         "smithy-rs#4117"
       ],
       "since-commit": "84f5464aacf3544f706d75af0aaddfea42c20e9f",
-      "age": 1
+      "age": 2
     },
     {
       "message": "Promote `aws-smithy-mocks-experimental` to `aws-smithy-mocks`. This crate is now a recommended tool for testing\ngenerated SDK clients. This release includes several fixes as well as a new sequence builder API that can be\nused to test more complex scenarios such as retries.\n\n```rust\nuse aws_sdk_s3::operation::get_object::GetObjectOutput;\nuse aws_sdk_s3::config::retry::RetryConfig;\nuse aws_smithy_types::byte_stream::ByteStream;\nuse aws_smithy_mocks::{mock, mock_client, RuleMode};\n\n#[tokio::test]\nasync fn test_retry_behavior() {\n    // Create a rule that returns 503 twice, then succeeds\n    let retry_rule = mock!(aws_sdk_s3::Client::get_object)\n        .sequence()\n        .http_status(503, None)\n        .times(2)                                            // Return 503 HTTP status twice\n        .output(|| GetObjectOutput::builder()                // Finally return a successful output\n            .body(ByteStream::from_static(b\"success\"))\n            .build())\n        .build();\n\n    // Create a mocked client with the rule\n    let s3 = mock_client!(\n        aws_sdk_s3,\n        RuleMode::Sequential,\n        [&retry_rule],\n        |client_builder| {\n            client_builder.retry_config(RetryConfig::standard().with_max_attempts(3))\n        }\n    );\n\n    // This should succeed after two retries\n    let result = s3\n        .get_object()\n        .bucket(\"test-bucket\")\n        .key(\"test-key\")\n        .send()\n        .await\n        .expect(\"success after retries\");\n\n    // Verify the response\n    let data = result.body.collect().await.expect(\"successful read\").to_vec();\n    assert_eq!(data, b\"success\");\n\n    // Verify all responses were used\n    assert_eq!(retry_rule.num_calls(), 3);\n}\n```\n",
@@ -102,7 +88,7 @@
         "smithy-rs#3926"
       ],
       "since-commit": "84f5464aacf3544f706d75af0aaddfea42c20e9f",
-      "age": 1
+      "age": 2
     },
     {
       "message": "Update MSRV to 1.82.0\n",
@@ -116,6 +102,20 @@
         "smithy-rs#4120"
       ],
       "since-commit": "84f5464aacf3544f706d75af0aaddfea42c20e9f",
+      "age": 2
+    },
+    {
+      "message": "Replace once_cell with std equivalents\n",
+      "meta": {
+        "bug": false,
+        "breaking": false,
+        "tada": false
+      },
+      "author": "FalkWoldmann",
+      "references": [
+        "smithy-rs#4105"
+      ],
+      "since-commit": "f3aebe7b53d7e1be4bd922e13d459f8ef72104fa",
       "age": 1
     }
   ],