Files
codex/codex-rs/core/src/tasks/compact.rs
Michael Bolin 7a3eec6fdb core: cut codex-core compile time 48% with native async SessionTask (#16631)
## Why

This continues the compile-time cleanup from #16630. `SessionTask`
implementations are monomorphized, but `Session` stores the task behind
a `dyn` boundary so it can drive and abort heterogenous turn tasks
uniformly. That means we can move the `#[async_trait]` expansion off the
implementation trait, keep a small boxed adapter only at the storage
boundary, and preserve the existing task lifecycle semantics while
reducing the amount of generated async-trait glue in `codex-core`.

One measurement caveat showed up while exploring this: a warm
incremental benchmark based on `touch core/src/tasks/mod.rs && cargo
check -p codex-core --lib` was basically flat, but that was the wrong
benchmark for this change. Using package-clean `codex-core` rebuilds,
like #16630, shows the real win.

Relevant pre-change code:

- [`SessionTask` with
`#[async_trait]`](3c7f013f97/codex-rs/core/src/tasks/mod.rs (L129-L182))
- [`RunningTask` storing `Arc<dyn
SessionTask>`](3c7f013f97/codex-rs/core/src/state/turn.rs (L69-L77))

## What changed

- Switched `SessionTask::{run, abort}` to native RPITIT futures with
explicit `Send` bounds.
- Added a private `AnySessionTask` adapter that boxes those futures only
at the `Arc<dyn ...>` storage boundary.
- Updated `RunningTask` to store `Arc<dyn AnySessionTask>` and removed
`#[async_trait]` from the concrete task impls plus test-only
`SessionTask` impls.

## Timing

Benchmarked package-clean `codex-core` rebuilds with dependencies left
warm:

```shell
cargo check -p codex-core --lib >/dev/null
cargo clean -p codex-core >/dev/null
/usr/bin/time -p cargo +nightly rustc -p codex-core --lib -- \
  -Z time-passes \
  -Z time-passes-format=json >/dev/null
```

| revision | rustc `total` | process `real` | `generate_crate_metadata`
| `MIR_borrow_checking` | `monomorphization_collector_graph_walk` |
| --- | ---: | ---: | ---: | ---: | ---: |
| parent `3c7f013f9735` | 67.21s | 67.71s | 24.61s | 23.43s | 22.43s |
| this PR `2cafd783ac22` | 35.08s | 35.60s | 8.01s | 7.25s | 7.15s |
| delta | -47.8% | -47.4% | -67.5% | -69.1% | -68.1% |

For completeness, the warm touched-file benchmark stayed flat (`1.96s`
parent vs `1.97s` this PR), which is why that benchmark should not be
used to evaluate this refactor.

## Verification

- Ran `cargo test -p codex-core`; this change compiled and task-related
tests passed before hitting the same unrelated 5
`config::tests::*guardian*` failures already present on the parent
stack.
2026-04-02 23:39:56 +00:00

48 lines
1.3 KiB
Rust

use std::sync::Arc;
use super::SessionTask;
use super::SessionTaskContext;
use crate::codex::TurnContext;
use crate::state::TaskKind;
use codex_protocol::user_input::UserInput;
use tokio_util::sync::CancellationToken;
#[derive(Clone, Copy, Default)]
pub(crate) struct CompactTask;
impl SessionTask for CompactTask {
fn kind(&self) -> TaskKind {
TaskKind::Compact
}
fn span_name(&self) -> &'static str {
"session_task.compact"
}
async fn run(
self: Arc<Self>,
session: Arc<SessionTaskContext>,
ctx: Arc<TurnContext>,
input: Vec<UserInput>,
_cancellation_token: CancellationToken,
) -> Option<String> {
let session = session.clone_session();
let _ = if crate::compact::should_use_remote_compact_task(&ctx.provider) {
session.services.session_telemetry.counter(
"codex.task.compact",
/*inc*/ 1,
&[("type", "remote")],
);
crate::compact_remote::run_remote_compact_task(session.clone(), ctx).await
} else {
session.services.session_telemetry.counter(
"codex.task.compact",
/*inc*/ 1,
&[("type", "local")],
);
crate::compact::run_compact_task(session.clone(), ctx, input).await
};
None
}
}