fix: more stable notify script (#13011)

codex-rs/core/tests/suite/user_notification.rs

@@ -23,10 +23,6 @@ use responses::start_mock_server;
 use std::time::Duration;
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-#[ignore = "flaky on ubuntu-24.04-arm - aarch64-unknown-linux-gnu"]
-// The notify script gets far enough to create (and therefore surface) the file,
-// but hasn’t flushed the JSON yet. Reading an empty file produces EOF while parsing
-// a value at line 1 column 0. May be caused by a slow runner.
 async fn summarize_context_three_requests_and_instructions() -> anyhow::Result<()> {
     skip_if_no_network!(Ok(()));
 
@@ -43,7 +39,10 @@ async fn summarize_context_three_requests_and_instructions() -> anyhow::Result<(
         &notify_script,
         r#"#!/bin/bash
 set -e
-echo -n "${@: -1}" > $(dirname "${0}")/notify.txt"#,
+payload_path="$(dirname "${0}")/notify.txt"
+tmp_path="${payload_path}.tmp"
+echo -n "${@: -1}" > "${tmp_path}"
+mv "${tmp_path}" "${payload_path}""#,
     )?;
     std::fs::set_permissions(&notify_script, std::fs::Permissions::from_mode(0o755))?;