fix(scope): close final ownership races

Drain idle injection flushes before agent teardown, snapshot approval and subagent provider inputs, and gate subagent lifecycle events on real child readiness. Align the RFCs and generated contracts with the hardened behavior.
This commit is contained in:
Tianyi Cui
2026-07-12 00:31:46 +08:00
parent e6c7522a75
commit 3529b3c166
43 changed files with 825 additions and 261 deletions

View File

@@ -62,11 +62,12 @@ interface SubagentStopReasonMap {
## A live run: `SubagentRun`
The handle the consumer holds while a child executes. The consumer awaits `result`, may `cancel` mid-flight, and MUST `dispose` on every path to reach child quiescence (no leaked idle child / session). `result` does NOT reject on a child-level failure — a model/transport failure resolves with `stopReason: 'error'` — so the consumer maps a non-`completed` reason to an `isError` result; it rejects only on an infrastructure fault the seam cannot represent. `sendMessage` and `resume` are OPTIONAL: a provider that supports the runtime capability defines the method; one that doesn't omits it.
The handle the consumer holds while a child executes. `started` is the provider's publication boundary: it resolves only after an in-process agent is live in `ctx.agents` or a remote transport has created its child session, and rejects when the attempt fails or is cancelled before that point. The consumer normally awaits `result`, may `cancel` mid-flight, and MUST `dispose` on every path to reach child quiescence (no leaked idle child / session). `result` does NOT reject on a child-level failure — a model/transport failure resolves with `stopReason: 'error'` — so the consumer maps a non-`completed` reason to an `isError` result; it rejects only on an infrastructure fault the seam cannot represent. `sendMessage` and `resume` are OPTIONAL: a provider that supports the runtime capability defines the method; one that doesn't omits it.
```ts type-equiv
interface SubagentRun {
readonly id: AgentId
readonly started: Promise<void>
readonly result: Promise<SubagentResult>
cancel(reason?: string): void
dispose(): Promise<void>
@@ -88,11 +89,11 @@ interface SubagentProvider {
}
```
The service (`ctx.subagents`) emits `subagent/start` when a run begins and `subagent/end` when it settles (see the [events catalog](../cordis-catalog/events.md)). `subagent/end` carries `lastAssistantMessage` (the child's final `output`) on the settle path, so an observer sees WHAT the subagent produced without holding the run (absent when the run rejected at the infrastructure level — no result was produced). These are **observe-only** events: both are plain `emit`s (the `subagent/end` fires from a detached `.then` after the result settles and awaits no listener), so a subscriber observes but cannot change the run. Both emits contain a thrown listener **per listener** (logged, never propagated): one bad subscriber can neither strand a live run, surface as an unhandled rejection on the detached settle hook, nor starve the listeners registered after it.
The service (`ctx.subagents`) emits `subagent/start` only after `run.started` fulfills and emits the paired `subagent/end` when that started run settles (see the [events catalog](../cordis-catalog/events.md)); a pre-publication readiness rejection emits neither event. For an in-process provider, a start listener can therefore resolve the live child with `ctx.agents.get(info.id)`; a remote provider need not publish into the local registry. `subagent/end` carries `lastAssistantMessage` (the child's final `output`) on the settle path, so an observer sees WHAT the subagent produced without holding the run (absent when the run rejected at the infrastructure level — no result was produced). These are **observe-only** events: both are plain `emit`s, so a subscriber observes but cannot change the run. Result settlement is observed immediately even while readiness is pending, then its cloned end payload is buffered until start has been announced; this prevents an early rejection from becoming unhandled while preserving start-before-end order and protecting the caller's result from listener mutation. Both emits contain a thrown listener **per listener** (logged, never propagated): one bad subscriber can neither strand a live run, surface as an unhandled rejection on the detached settle hook, nor starve the listeners registered after it.
## In-process backends: depth and seed
The two in-process backends ([dsh-subagent-spawn](../../packages/subagent/subagent-spawn) fresh, [dsh-subagent-fork](../../packages/subagent/subagent-fork) seeded) run the child as a child `Agent` on the same application. They synchronously snapshot caller-owned data, install provider ownership before attaching the abort listener, create one run-owner fiber under `parent.ctx`, and invoke the factory through that fiber: parent teardown, provider teardown, and manual run disposal share the same pre-publication ownership and quiescence boundary, while the child still receives a flat new scope rather than inheriting the parent's capabilities. Two pieces of vocabulary ride on the existing agent/session types rather than new core types:
The two in-process backends ([dsh-subagent-spawn](../../packages/subagent/subagent-spawn) fresh, [dsh-subagent-fork](../../packages/subagent/subagent-fork) seeded) run the child as a child `Agent` on the same application. They synchronously snapshot caller-owned data, install provider ownership before attaching the abort listener, create one run-owner fiber under `parent.ctx`, and invoke the factory through that fiber: parent teardown, provider teardown, and manual run disposal share the same pre-publication ownership and quiescence boundary, while the child still receives a flat new scope rather than inheriting the parent's capabilities. Their `started` promise projects the factory's successful publication and the result driver awaits that same promise before sending the prompt. Two pieces of vocabulary ride on the existing agent/session types rather than new core types:
- **Delegation depth** is a merge-extensible `AgentOptions.subagentDepth` field (`0` for a top-level agent, parent + 1 for a child). The seam owns it — the loop neither sets nor reads it — so a nested spawn reads its parent's depth from `parent.options.subagentDepth` and the `depthLimit` capability caps the tree by refusing a child whose depth would exceed `request.maxDepth`.
- **Fork seeding** uses `CreateAgentOptions.seed` (a `SessionEvent[]` prefix threaded through `AgentLoop.createAgent` → `ctx.sessions.prepare({ seed })`, the same primitive `resume` uses). The fork backend passes a *balanced completed-turn prefix* of the parent's log — the parent's events up to and including its last `turn/end` — so the seed is contiguous-from-0 and the [invariants](../../packages/support/invariants) replay accepts it (the in-flight, unbalanced turn is excluded).