From 660395c47d0c02b42adedfaf676b62f0de72c21c Mon Sep 17 00:00:00 2001
From: Owen Lin <owen@openai.com>
Date: Thu, 9 Jul 2026 21:55:48 -0700
Subject: [PATCH] codex: fix CI failure on PR #31859

---
 codex-rs/rollout/src/ordinal.rs        | 13 ++++++-------
 codex-rs/rollout/src/recorder_tests.rs | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/codex-rs/rollout/src/ordinal.rs b/codex-rs/rollout/src/ordinal.rs
index c87b32c02b..7325b29793 100644
--- a/codex-rs/rollout/src/ordinal.rs
+++ b/codex-rs/rollout/src/ordinal.rs
@@ -53,7 +53,9 @@ pub(crate) async fn ordinal_state_for_rollout(path: &Path) -> io::Result<Rollout
 }
 
 fn ordinal_state_for_rollout_blocking(path: &Path) -> io::Result<RolloutOrdinalState> {
-    let history_mode = read_history_mode(path)?;
+    let Some(history_mode) = read_history_mode(path)? else {
+        return Ok(RolloutOrdinalState::Legacy);
+    };
     if matches!(history_mode, ThreadHistoryMode::Legacy) {
         return Ok(RolloutOrdinalState::Legacy);
     }
@@ -82,7 +84,7 @@ fn ordinal_state_for_rollout_blocking(path: &Path) -> io::Result<RolloutOrdinalS
     })
 }
 
-fn read_history_mode(path: &Path) -> io::Result<ThreadHistoryMode> {
+fn read_history_mode(path: &Path) -> io::Result<Option<ThreadHistoryMode>> {
     let reader = BufReader::new(File::open(path)?);
     for line in reader.lines() {
         let line = line?;
@@ -101,10 +103,7 @@ fn read_history_mode(path: &Path) -> io::Result<ThreadHistoryMode> {
                 path.display()
             )));
         };
-        return Ok(session_meta.meta.history_mode);
+        return Ok(Some(session_meta.meta.history_mode));
     }
-    Err(io::Error::other(format!(
-        "rollout at {} contains no records",
-        path.display()
-    )))
+    Ok(None)
 }
diff --git a/codex-rs/rollout/src/recorder_tests.rs b/codex-rs/rollout/src/recorder_tests.rs
index a5efbaafa1..bece7643d7 100644
--- a/codex-rs/rollout/src/recorder_tests.rs
+++ b/codex-rs/rollout/src/recorder_tests.rs
@@ -608,6 +608,30 @@ async fn recorder_omits_ordinals_from_legacy_rollouts() -> std::io::Result<()> {
     recorder.shutdown().await
 }
 
+#[tokio::test]
+async fn resumed_empty_rollout_omits_ordinals() -> std::io::Result<()> {
+    let home = TempDir::new().expect("temp dir");
+    let config = test_config(home.path());
+    let rollout_path = home.path().join("rollout.jsonl");
+    File::create(&rollout_path)?;
+
+    let recorder =
+        RolloutRecorder::new(&config, RolloutRecorderParams::resume(rollout_path.clone())).await?;
+    recorder
+        .record_canonical_items(&[agent_message_item("legacy")])
+        .await?;
+    recorder.flush().await?;
+
+    let text = fs::read_to_string(rollout_path)?;
+    let values = text
+        .lines()
+        .map(serde_json::from_str::<serde_json::Value>)
+        .collect::<Result<Vec<_>, _>>()?;
+    assert!(values.iter().all(|value| value.get("ordinal").is_none()));
+
+    recorder.shutdown().await
+}
+
 #[tokio::test]
 async fn persist_reports_filesystem_error_and_retries_buffered_items() -> std::io::Result<()> {
     let home = TempDir::new().expect("temp dir");