Treat interrupted fork snapshots as closed

Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/src/thread_manager.rs

@@ -26,6 +26,7 @@ use crate::shell_snapshot::ShellSnapshot;
 use crate::skills::SkillsManager;
 use crate::tasks::interrupted_turn_history_marker;
 use codex_app_server_protocol::ThreadHistoryBuilder;
+use codex_app_server_protocol::protocol::v2::TurnStatus;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::CollaborationModeMask;
 #[cfg(test)]
@@ -936,9 +937,20 @@ fn snapshot_turn_state(history: &InitialHistory) -> SnapshotTurnState {
         builder.handle_rollout_item(item);
     }
     if builder.has_active_turn() {
+        let active_turn_snapshot = builder.active_turn_snapshot();
+        if active_turn_snapshot
+            .as_ref()
+            .is_some_and(|turn| turn.status == TurnStatus::Interrupted)
+        {
+            return SnapshotTurnState {
+                ends_mid_turn: false,
+                active_turn_id: None,
+            };
+        }
+
         return SnapshotTurnState {
             ends_mid_turn: true,
-            active_turn_id: builder.active_turn_snapshot().map(|turn| turn.id),
+            active_turn_id: active_turn_snapshot.map(|turn| turn.id),
         };
     }
 

codex-rs/core/src/thread_manager_tests.rs

@@ -255,6 +255,27 @@ fn interrupted_fork_snapshot_appends_interrupt_boundary() {
     );
 }
 
+#[test]
+fn interrupted_snapshot_is_not_mid_turn() {
+    let interrupted_history = InitialHistory::Forked(vec![
+        RolloutItem::ResponseItem(user_msg("hello")),
+        RolloutItem::ResponseItem(assistant_msg("partial")),
+        RolloutItem::ResponseItem(interrupted_turn_history_marker()),
+        RolloutItem::EventMsg(EventMsg::TurnAborted(TurnAbortedEvent {
+            turn_id: Some("turn-1".to_string()),
+            reason: TurnAbortReason::Interrupted,
+        })),
+    ]);
+
+    assert_eq!(
+        snapshot_turn_state(&interrupted_history),
+        SnapshotTurnState {
+            ends_mid_turn: false,
+            active_turn_id: None,
+        },
+    );
+}
+
 #[tokio::test]
 async fn interrupted_fork_snapshot_preserves_persisted_turn_id() {
     let temp_dir = tempdir().expect("tempdir");