Honor an already-aborted signal in the subagent tool bridge (review feedback)

addEventListener('abort') does not fire for a signal already aborted before the listener is added, so a parent step cancelled before the subagent tool ran would never reach the child — the tool leaned on each provider re-checking request.signal itself, leaving the bridge's own claim incomplete for any provider that relies on run.cancel(). Re-check exec.signal.aborted right after registering and cancel explicitly. Regression test uses a spy provider that only reacts to cancel() (never inspects the signal); proven to hang without the fix (result never settles) and settle aborted with it.
2026-06-22 16:32:10 +08:00
parent 8d111161de
commit 8723186398
2 changed files with 42 additions and 0 deletions
@@ -136,6 +136,11 @@ export function apply(ctx: Context, config: Config): void {
      // aborted while the child is in flight, cancel the child too.
      const onAbort = (): void => { run.cancel('parent step aborted') }
      exec.signal?.addEventListener('abort', onAbort, { once: true })
+      // `addEventListener` does NOT fire for a signal already aborted before this
+      // line, so a step cancelled before the tool ran would never reach the
+      // child. Cancel explicitly in that case — the bridge must honor an
+      // already-aborted signal, not lean on each provider re-checking it.
+      if (exec.signal?.aborted) run.cancel('parent step aborted')

      try {
        const result = await run.result