fix(ui): report session persistence failures on shutdown

changelog.d/storage-shutdown-persistence.fixed.md

@@ -0,0 +1 @@
+Report storage writer shutdown failures instead of silently accepting unpersisted session snapshots.

n00n-storage/src/sessions.rs

@@ -3283,15 +3283,18 @@ where
     }
 
     /// # Errors
-    /// Returns `SessionError` if the session file cannot be found or removed.
+    /// Returns `SessionError` if the session file cannot be found or cleanup fails.
     pub fn delete_from(id: n00nId, dir: &Path) -> Result<(), SessionError> {
         let _lock = lock_openai_response_chain_in(dir, id)?;
-        let Some(path) = locate_session_file(dir, id) else {
-            return Err(StorageError::NotFound(id.to_string()).into());
-        };
-        try_remove(&path)?;
+        let path = locate_session_file(dir, id);
+        if let Some(path) = &path {
+            try_remove(path)?;
+        }
         try_remove(&openai_response_chain_path(dir, id))?;
         remove_from_cwd_index(dir, id)?;
+        if path.is_none() {
+            return Err(StorageError::NotFound(id.to_string()).into());
+        }
         Ok(())
     }
 
@@ -4740,6 +4743,30 @@ mod tests {
         ));
     }
 
+    #[test]
+    fn delete_missing_primary_cleans_sidecar_and_cwd_index() {
+        let tmp = TempDir::new().unwrap();
+        let dir = tmp.path();
+        let mut session: TestSession = Session::new("m", "/orphaned");
+        session.save_to(dir).unwrap();
+        let sidecar = openai_response_chain_path(dir, session.id);
+        fs::write(&sidecar, b"orphaned").unwrap();
+        fs::remove_file(jsonl_path(dir, session.id)).unwrap();
+
+        let error = TestSession::delete_from(session.id, dir).unwrap_err();
+
+        assert!(matches!(
+            error,
+            SessionError::Storage(StorageError::NotFound(_))
+        ));
+        assert!(!sidecar.exists());
+        assert!(
+            !load_cwd_index(dir)
+                .values()
+                .any(|value| *value == session.id.to_string())
+        );
+    }
+
     #[test]
     fn title_unicode_safe() {
         let input = "あ".repeat(100);

n00n-ui/src/app/mod.rs

@@ -218,7 +218,13 @@ impl Drop for TestStateDir {
             return;
         };
         let writer_stopped = match Arc::try_unwrap(writer) {
-            Ok(writer) => writer.wait_for_shutdown(TEST_WRITER_DRAIN_TIMEOUT),
+            Ok(writer) => match writer.wait_for_shutdown(TEST_WRITER_DRAIN_TIMEOUT) {
+                Ok(()) => true,
+                Err(error) => {
+                    tracing::warn!(%error, "test storage writer shutdown failed");
+                    false
+                }
+            },
             Err(writer) => {
                 drop(writer);
                 false

n00n-ui/src/app/tests.rs

@@ -2551,7 +2551,8 @@ fn drain_writer(app: App, writer: Arc<StorageWriter>) {
     Arc::try_unwrap(writer)
         .ok()
         .expect("app must hold the only other writer reference")
-        .shutdown(WRITER_DRAIN_TIMEOUT);
+        .shutdown(WRITER_DRAIN_TIMEOUT)
+        .unwrap();
 }
 
 #[test]
@@ -2730,7 +2731,8 @@ fn draw_failure_pending_submission_restores_fifo_images_and_control_after_restar
     Arc::try_unwrap(writer)
         .ok()
         .expect("test owns the storage writer")
-        .shutdown(WRITER_DRAIN_TIMEOUT);
+        .shutdown(WRITER_DRAIN_TIMEOUT)
+        .unwrap();
 
     let writer = Arc::new(StorageWriter::new(dir.clone()).unwrap());
     let mut restarted = build_app(dir.clone(), Arc::clone(&writer));
@@ -2769,7 +2771,8 @@ fn draw_failure_pending_submission_restores_fifo_images_and_control_after_restar
     Arc::try_unwrap(writer)
         .ok()
         .expect("test owns the restarted storage writer")
-        .shutdown(WRITER_DRAIN_TIMEOUT);
+        .shutdown(WRITER_DRAIN_TIMEOUT)
+        .unwrap();
 }
 
 #[test]
@@ -2831,7 +2834,8 @@ fn mcp_prompt_draw_failure_survives_restart_without_text_fallback() {
     Arc::try_unwrap(writer)
         .ok()
         .expect("test owns the storage writer")
-        .shutdown(WRITER_DRAIN_TIMEOUT);
+        .shutdown(WRITER_DRAIN_TIMEOUT)
+        .unwrap();
 
     let writer = Arc::new(StorageWriter::new(dir.clone()).unwrap());
     let mut restarted = build_app_with_mcp(dir.clone(), Arc::clone(&writer), mcp_reader);
@@ -2865,7 +2869,8 @@ fn mcp_prompt_draw_failure_survives_restart_without_text_fallback() {
     Arc::try_unwrap(writer)
         .ok()
         .expect("test owns the restarted storage writer")
-        .shutdown(WRITER_DRAIN_TIMEOUT);
+        .shutdown(WRITER_DRAIN_TIMEOUT)
+        .unwrap();
 }
 
 #[test]

n00n-ui/src/event_loop.rs

@@ -62,6 +62,8 @@ const PERIODIC_SAVE_INTERVAL: Duration = Duration::from_secs(1);
 const DRAIN_BUDGET: usize = 256;
 const AGENT_SHUTDOWN_TIMEOUT: Duration = Duration::from_secs(3);
 const STORAGE_WRITER_SHUTDOWN_TIMEOUT: Duration = Duration::from_secs(5);
+const STORAGE_WRITER_REFS_ERR: &str =
+    "storage writer has outstanding references, skipping graceful shutdown";
 const DELETE_FOCUSED_ERR: &str = "cannot delete the focused session";
 const NOT_LIVE_ERR: &str = "session not live";
 const TEAM_TOOL_NAME: &str = "team";
@@ -606,8 +608,16 @@ impl<'t> EventLoop<'t> {
         // Fatal errors still save every session, shut down MCP transports
         // (terminating and reaping their child processes), and drain the
         // storage writer before the process exits.
-        let report = self.shutdown();
-        result.map(|()| report)
+        let shutdown = self.shutdown();
+        match result {
+            Ok(()) => shutdown,
+            Err(error) => {
+                if let Err(shutdown_error) = shutdown {
+                    warn!(error = %shutdown_error, "shutdown after fatal error was incomplete");
+                }
+                Err(error)
+            }
+        }
     }
 
     /// Wait for the next event from any source, or time out so animations
@@ -1490,7 +1500,7 @@ impl<'t> EventLoop<'t> {
         }
     }
 
-    fn shutdown(mut self) -> ShutdownReport {
+    fn shutdown(mut self) -> Result<ShutdownReport> {
         self.preserve_post_draw_submissions();
         let exit = self.sessions[self.focused].app.exit_request;
         for rt in &self.sessions {
@@ -1512,17 +1522,19 @@ impl<'t> EventLoop<'t> {
             smol::block_on(h.shutdown());
         }
         crate::agent::join_all(agent_tasks, AGENT_SHUTDOWN_TIMEOUT);
-        match Arc::try_unwrap(self.ctx.storage_writer) {
-            Ok(writer) => writer.shutdown(STORAGE_WRITER_SHUTDOWN_TIMEOUT),
-            Err(_) => {
-                warn!("storage writer has outstanding references, skipping graceful shutdown");
-            }
-        }
-        ShutdownReport {
+        let storage_result = match Arc::try_unwrap(self.ctx.storage_writer) {
+            Ok(writer) => writer
+                .shutdown(STORAGE_WRITER_SHUTDOWN_TIMEOUT)
+                .map_err(Into::into),
+            Err(_) => Err(eyre!(STORAGE_WRITER_REFS_ERR)),
+        };
+        let report = ShutdownReport {
             exit,
             tabs,
             focused: self.focused,
-        }
+        };
+        storage_result?;
+        Ok(report)
     }
 }