## Problem
The app-server TUI (`tui_app_server`) lacked composer history support.
Pressing Up/Down to recall previous prompts hit a stub that logged a
warning and displayed "Not available in app-server TUI yet." New
submissions were silently dropped from the shared history file, so
nothing persisted for future sessions.
## Mental model
Codex maintains a single, append-only history file
(`$CODEX_HOME/history.jsonl`) shared across all TUI processes on the
same machine. The legacy (in-process) TUI already reads/writes this file
through `codex_core::message_history`. The app-server TUI delegates most
operations to a separate process over RPC, but history is intentionally
*not* an RPC concern — it's a client-local file.
This PR makes the app-server TUI access the same history file directly,
bypassing the app-server process entirely. The composer's Up/Down
navigation and submit-time persistence now follow the same code paths as
the legacy TUI, with the only difference being *where* the call is
dispatched (locally in `App`, rather than inside `CodexThread`).
The branch is rebuilt directly on top of `upstream/main`, so it keeps
the
existing app-server restore architecture intact.
`AppServerStartedThread`
still restores transcript history from the server `Thread` snapshot via
`thread_snapshot_events`; this PR only adds composer-history support.
## Non-goals
- Adding history support to the app-server protocol. History remains
client-local.
- Changing the on-disk format or location of `history.jsonl`.
- Surfacing history I/O errors to the user (failures are logged and
silently swallowed, matching the legacy TUI).
## Tradeoffs
| Decision | Why | Risk |
|----------|-----|------|
| Widen `message_history` from `pub(crate)` to `pub` | Avoids
duplicating file I/O logic; the module already has a clean, minimal API
surface. | Other workspace crates can now call these functions — the
contract is no longer crate-private. However, this is consistent with
recent precedent: `590cfa617` exposed `mention_syntax` for TUI
consumption, `752402c4f` exposed plugin APIs (`PluginsManager`), and
`14fcb6645`/`edacbf7b6` widened internal core APIs for other crates.
These were all narrow, intentional exposures of specific APIs — not
broad "make internals public" moves. `1af2a37ad` even went the other
direction, reducing broad re-exports to tighten boundaries. This change
follows the same pattern: a small, deliberate API surface (3 functions)
rather than a wholesale visibility change. |
| Intercept `AddToHistory` / `GetHistoryEntryRequest` in `App` before
RPC fallback | Keeps history ops out of the "unsupported op" error path
without changing app-server protocol. | This now routes through a single
`submit_thread_op` entry point, which is safer than the original
duplicated dispatch. The remaining risk is organizational: future
thread-op submission paths need to keep using that shared entry point. |
| `session_configured_from_thread_response` is now `async` | Needs
`await` on `history_metadata()` to populate real `history_log_id` /
`history_entry_count`. | Adds an async file-stat + full-file newline
scan to the session bootstrap path. The scan is bounded by
`history.max_bytes` and matches the legacy TUI's cost profile, but
startup latency still scales with file size. |
## Architecture
```
User presses Up User submits a prompt
│ │
▼ ▼
ChatComposerHistory ChatWidget::do_submit_turn
navigate_up() encode_history_mentions()
│ │
▼ ▼
AppEvent::CodexOp Op::AddToHistory { text }
(GetHistoryEntryRequest) │
│ ▼
▼ App::try_handle_local_history_op
App::try_handle_local_history_op message_history::append_entry()
spawn_blocking { │
message_history::lookup() ▼
} $CODEX_HOME/history.jsonl
│
▼
AppEvent::ThreadEvent
(GetHistoryEntryResponse)
│
▼
ChatComposerHistory::on_entry_response()
```
## Observability
- `tracing::warn` on `append_entry` failure (includes thread ID).
- `tracing::warn` on `spawn_blocking` lookup join error.
- `tracing::warn` from `message_history` internals on file-open, lock,
or parse failures.
## Tests
- `chat_composer_history::tests::navigation_with_async_fetch` — verifies
that Up emits `Op::GetHistoryEntryRequest` (was: checked for stub error
cell).
- `app::tests::history_lookup_response_is_routed_to_requesting_thread` —
verifies multi-thread composer recall routes the lookup result back to
the originating thread.
-
`app_server_session::tests::resume_response_relies_on_snapshot_replay_not_initial_messages`
— verifies app-server session restore still uses the upstream
thread-snapshot path.
-
`app_server_session::tests::session_configured_populates_history_metadata`
— verifies bootstrap sets nonzero `history_log_id` /
`history_entry_count` from the shared local history file.
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