diff --git a/codex-rs/rollout/src/compression_tests.rs b/codex-rs/rollout/src/compression_tests.rs
index 4777aa7321..7dde0735cf 100644
--- a/codex-rs/rollout/src/compression_tests.rs
+++ b/codex-rs/rollout/src/compression_tests.rs
@@ -243,6 +243,7 @@ fn write_rollout(path: &std::path::Path, thread_id: ThreadId, message: &str) ->
         meta: SessionMeta {
             id: thread_id,
             forked_from_id: None,
+            parent_thread_id: None,
             timestamp: "2025-01-03T12:00:00Z".to_string(),
             cwd: parent.to_path_buf(),
             originator: "test".to_string(),