Reduce typed app-server request serialization overhead (#34766)

## What changed

- Use `ClientRequest::method_name()` directly when preparing typed request
  diagnostics for in-process and remote clients.
- Allocate the owned method name only when constructing an error.
- Remove the serialization-based method lookup and the redundant allocating
  `ClientRequest::method()` helper.

GitOrigin-RevId: 93859e512a4f20204e0db4f929a2baebe4374ec5

codex-rs/app-server-client/src/lib.rs

@@ -617,20 +617,22 @@ impl InProcessAppServerClient {
     where
         T: DeserializeOwned,
     {
-        let method = request_method_name(&request);
+        let method = request.method_name();
         let response =
             self.request(request)
                 .await
                 .map_err(|source| TypedRequestError::Transport {
-                    method: method.clone(),
+                    method: method.to_string(),
                     source,
                 })?;
         let result = response.map_err(|source| TypedRequestError::Server {
-            method: method.clone(),
+            method: method.to_string(),
             source,
         })?;
-        serde_json::from_value(result)
-            .map_err(|source| TypedRequestError::Deserialize { method, source })
+        serde_json::from_value(result).map_err(|source| TypedRequestError::Deserialize {
+            method: method.to_string(),
+            source,
+        })
     }
 
     /// Sends a typed client notification.
@@ -790,20 +792,22 @@ impl InProcessAppServerRequestHandle {
     where
         T: DeserializeOwned,
     {
-        let method = request_method_name(&request);
+        let method = request.method_name();
         let response =
             self.request(request)
                 .await
                 .map_err(|source| TypedRequestError::Transport {
-                    method: method.clone(),
+                    method: method.to_string(),
                     source,
                 })?;
         let result = response.map_err(|source| TypedRequestError::Server {
-            method: method.clone(),
+            method: method.to_string(),
             source,
         })?;
-        serde_json::from_value(result)
-            .map_err(|source| TypedRequestError::Deserialize { method, source })
+        serde_json::from_value(result).map_err(|source| TypedRequestError::Deserialize {
+            method: method.to_string(),
+            source,
+        })
     }
 }
 
@@ -904,20 +908,6 @@ impl AppServerClient {
     }
 }
 
-/// Extracts the JSON-RPC method name for diagnostics without extending the
-/// protocol crate with in-process-only helpers.
-pub(crate) fn request_method_name(request: &ClientRequest) -> String {
-    serde_json::to_value(request)
-        .ok()
-        .and_then(|value| {
-            value
-                .get("method")
-                .and_then(serde_json::Value::as_str)
-                .map(ToOwned::to_owned)
-        })
-        .unwrap_or_else(|| "<unknown>".to_string())
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

codex-rs/app-server-client/src/remote.rs

@@ -21,7 +21,6 @@ use crate::AppServerEvent;
 use crate::RequestResult;
 use crate::SHUTDOWN_TIMEOUT;
 use crate::TypedRequestError;
-use crate::request_method_name;
 use codex_app_server_protocol::ClientInfo;
 use codex_app_server_protocol::ClientNotification;
 use codex_app_server_protocol::ClientRequest;
@@ -498,20 +497,22 @@ impl RemoteAppServerClient {
     where
         T: DeserializeOwned,
     {
-        let method = request_method_name(&request);
+        let method = request.method_name();
         let response =
             self.request(request)
                 .await
                 .map_err(|source| TypedRequestError::Transport {
-                    method: method.clone(),
+                    method: method.to_string(),
                     source,
                 })?;
         let result = response.map_err(|source| TypedRequestError::Server {
-            method: method.clone(),
+            method: method.to_string(),
             source,
         })?;
-        serde_json::from_value(result)
-            .map_err(|source| TypedRequestError::Deserialize { method, source })
+        serde_json::from_value(result).map_err(|source| TypedRequestError::Deserialize {
+            method: method.to_string(),
+            source,
+        })
     }
 
     pub async fn notify(&self, notification: ClientNotification) -> IoResult<()> {
@@ -658,20 +659,22 @@ impl RemoteAppServerRequestHandle {
     where
         T: DeserializeOwned,
     {
-        let method = request_method_name(&request);
+        let method = request.method_name();
         let response =
             self.request(request)
                 .await
                 .map_err(|source| TypedRequestError::Transport {
-                    method: method.clone(),
+                    method: method.to_string(),
                     source,
                 })?;
         let result = response.map_err(|source| TypedRequestError::Server {
-            method: method.clone(),
+            method: method.to_string(),
             source,
         })?;
-        serde_json::from_value(result)
-            .map_err(|source| TypedRequestError::Deserialize { method, source })
+        serde_json::from_value(result).map_err(|source| TypedRequestError::Deserialize {
+            method: method.to_string(),
+            source,
+        })
     }
 }
 

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -239,10 +239,6 @@ macro_rules! client_request_definitions {
                 }
             }
 
-            pub fn method(&self) -> String {
-                self.method_name().to_string()
-            }
-
             pub fn serialization_scope(&self) -> Option<ClientRequestSerializationScope> {
                 match self {
                     $(
@@ -2671,7 +2667,6 @@ mod tests {
             params: None,
         };
         assert_eq!(request.id(), &RequestId::Integer(1));
-        assert_eq!(request.method(), "account/rateLimits/read");
         assert_eq!(
             json!({
                 "method": "account/rateLimits/read",
@@ -2689,7 +2684,6 @@ mod tests {
             params: None,
         };
         assert_eq!(request.id(), &RequestId::Integer(1));
-        assert_eq!(request.method(), "account/usage/read");
         assert_eq!(
             json!({
                 "method": "account/usage/read",
@@ -2707,7 +2701,6 @@ mod tests {
             params: None,
         };
         assert_eq!(request.id(), &RequestId::Integer(1));
-        assert_eq!(request.method(), "account/workspaceMessages/read");
         assert_eq!(
             json!({
                 "method": "account/workspaceMessages/read",