This PR is part of the effort to move the TUI on top of the app server.
In a previous PR, we introduced an in-process app server and moved
`exec` on top of it.
For the TUI, we want to do the migration in stages. The app server
doesn't currently expose all of the functionality required by the TUI,
so we're going to need to support a hybrid approach as we make the
transition.
This PR changes the TUI initialization to instantiate an in-process app
server and access its `AuthManager` and `ThreadManager` rather than
constructing its own copies. It also adds a placeholder TUI event
handler that will eventually translate app server events into TUI
events. App server notifications are accepted but ignored for now. It
also adds proper shutdown of the app server when the TUI terminates.
This makes the test less flaky by checking the core invariant instead of
the full span chain.
Before, the test waited for several specific internal spans
(`submission_dispatch`, `session_task.turn`, `run_turn`) and asserted
their exact relationships. That was brittle because those spans are
exported asynchronously and are more of an implementation detail than
the thing we actually care about.
Now, the test only checks that:
- `turn/start` is on the expected remote trace with the expected remote
parent
- at least one representative core turn span on that same trace descends
from it
That keeps the sanity-check we want while making the test less sensitive
to timing and internal refactors.
## Summary
This PR keeps app-server RPC request trace context alive for the full
lifetime of the work that request kicks off (e.g. for `thread/start`,
this is `app-server rpc handler -> tokio background task -> core op
submissions`). Previously we lose trace lineage once the request handler
returns or hands work off to background tasks.
This approach is especially relevant for `thread/start` and other RPC
handlers that run in a non-blocking way. In the near future we'll most
likely want to make all app-server handlers run in a non-blocking way by
default, and only queue operations that must operate in order (e.g.
thread RPCs per thread?), so we want to make sure tracing in app-server
just generally works.
Depends on https://github.com/openai/codex/pull/14300
**Before**
<img width="155" height="207" alt="image"
src="https://github.com/user-attachments/assets/c9487459-36f1-436c-beb7-fafeb40737af"
/>
**After**
<img width="299" height="337" alt="image"
src="https://github.com/user-attachments/assets/727392b2-d072-4427-9dc4-0502d8652dea"
/>
## What changed
- Keep request-scoped trace context around until we send the final
response or error, or the connection closes.
- Thread that trace context through detached `thread/start` work so
background startup stays attached to the originating request.
- Pass request trace context through to downstream core operations,
including:
- thread creation
- resume/fork flows
- turn submission
- review
- interrupt
- realtime conversation operations
- Add tracing tests that verify:
- remote W3C trace context is preserved for `thread/start`
- remote W3C trace context is preserved for `turn/start`
- downstream core spans stay under the originating request span
- request-scoped tracing state is cleaned up correctly
- Clean up shutdown behavior so detached background tasks and spawned
threads are drained before process exit.
