Make OperationExtension store the absolute shape ID (#2276)

* Do not alter Operation shape ID

* Add OperationExtensionExt test

* Add CHANGELOG.next.toml entry

* Apply suggestions from code review

Co-authored-by: Luca Palmieri <20745048+LukeMathWalker@users.noreply.github.com>

---------

Co-authored-by: Luca Palmieri <20745048+LukeMathWalker@users.noreply.github.com>

Author: hlbarber

CHANGELOG.next.toml

@@ -82,3 +82,45 @@ message = "Fix broken doc link for `tokio_stream::Stream` that is a re-export of
 references = ["smithy-rs#2271"]
 meta = { "breaking" = false, "tada" = false, "bug" = true }
 author = "ysaito1001"
+
+[[smithy-rs]]
+message = """
+Fix `name` and `absolute` methods on `OperationExtension`.
+
+The older, [now removed](https://github.com/awslabs/smithy-rs/pull/2161), service builder would insert `OperationExtension` into the `http::Response` containing the [absolute shape ID](https://smithy.io/2.0/spec/model.html#grammar-token-smithy-AbsoluteRootShapeId) with the `#` symbol replaced with a `.`. When [reintroduced](https://github.com/awslabs/smithy-rs/pull/2157) into the new service builder machinery the behavior was changed - we now do _not_ perform the replace. This change fixes the documentation and `name`/`absolute` methods of the `OperationExtension` API to match this new behavior.
+
+In the old service builder, `OperationExtension` was initialized, by the framework, and then used as follows:
+
+```rust
+let ext = OperationExtension::new("com.amazonaws.CompleteSnapshot");
+
+// This is expected
+let name = ext.name(); // "CompleteSnapshot"
+let namespace = ext.namespace(); // = "com.amazonaws";
+```
+
+When reintroduced, `OperationExtension` was initialized by the `Plugin` and then used as follows:
+
+```rust
+let ext = OperationExtension::new("com.amazonaws#CompleteSnapshot");
+
+// This is the bug
+let name = ext.name(); // "amazonaws#CompleteSnapshot"
+let namespace = ext.namespace(); // = "com";
+```
+
+The intended behavior is now restored:
+
+```rust
+let ext = OperationExtension::new("com.amazonaws#CompleteSnapshot");
+
+// This is expected
+let name = ext.name(); // "CompleteSnapshot"
+let namespace = ext.namespace(); // = "com.amazonaws";
+```
+
+The rationale behind this change is that the previous design was tailored towards a specific internal use case and shouldn't be enforced on all customers.
+"""
+references = ["smithy-rs#2276"]
+meta = { "breaking" = true, "tada" = false, "bug" = true, "target" = "server"}
+author = "hlbarber"

rust-runtime/aws-smithy-http-server/src/extension.rs

@@ -35,9 +35,7 @@ pub use crate::request::extension::{Extension, MissingExtension};
 /// This extension type is inserted, via the [`OperationExtensionPlugin`], whenever it has been correctly determined
 /// that the request should be routed to a particular operation. The operation handler might not even get invoked
 /// because the request fails to deserialize into the modeled operation input.
-///
-/// The format given must be the absolute shape ID with `#` replaced with a `.`.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct OperationExtension {
     absolute: &'static str,
 
@@ -49,16 +47,16 @@ pub struct OperationExtension {
 #[derive(Debug, Clone, Error, PartialEq, Eq)]
 #[non_exhaustive]
 pub enum ParseError {
-    #[error(". was not found - missing namespace")]
+    #[error("# was not found - missing namespace")]
     MissingNamespace,
 }
 
 #[allow(deprecated)]
 impl OperationExtension {
-    /// Creates a new [`OperationExtension`] from the absolute shape ID of the operation with `#` symbol replaced with a `.`.
+    /// Creates a new [`OperationExtension`] from the absolute shape ID.
     pub fn new(absolute_operation_id: &'static str) -> Result<Self, ParseError> {
         let (namespace, name) = absolute_operation_id
-            .rsplit_once('.')
+            .rsplit_once('#')
             .ok_or(ParseError::MissingNamespace)?;
         Ok(Self {
             absolute: absolute_operation_id,
@@ -236,11 +234,15 @@ impl Deref for RuntimeErrorExtension {
 
 #[cfg(test)]
 mod tests {
+    use tower::{service_fn, ServiceExt};
+
+    use crate::{operation::OperationShapeExt, proto::rest_json_1::RestJson1};
+
     use super::*;
 
     #[test]
     fn ext_accept() {
-        let value = "com.amazonaws.ebs.CompleteSnapshot";
+        let value = "com.amazonaws.ebs#CompleteSnapshot";
         let ext = OperationExtension::new(value).unwrap();
 
         assert_eq!(ext.absolute(), value);
@@ -256,4 +258,33 @@ mod tests {
             ParseError::MissingNamespace
         )
     }
+
+    #[tokio::test]
+    async fn plugin() {
+        struct DummyOp;
+
+        impl OperationShape for DummyOp {
+            const NAME: &'static str = "com.amazonaws.ebs#CompleteSnapshot";
+
+            type Input = ();
+            type Output = ();
+            type Error = ();
+        }
+
+        // Apply `Plugin`.
+        let operation = DummyOp::from_handler(|_| async { Ok(()) });
+        let plugins = PluginPipeline::new().insert_operation_extension();
+        let op = Plugin::<RestJson1, DummyOp, _, _>::map(&plugins, operation);
+
+        // Apply `Plugin`s `Layer`.
+        let layer = op.layer;
+        let svc = service_fn(|_: http::Request<()>| async { Ok::<_, ()>(http::Response::new(())) });
+        let svc = layer.layer(svc);
+
+        // Check for `OperationExtension`.
+        let response = svc.oneshot(http::Request::new(())).await.unwrap();
+        let expected = OperationExtension::new(DummyOp::NAME).unwrap();
+        let actual = response.extensions().get::<OperationExtension>().unwrap();
+        assert_eq!(*actual, expected);
+    }
 }