Fence legacy sandbox dispatch against startup cancellation

Reconcile persisted cancellation with newly registered scopes, check cancellation before dispatch, and preserve external child termination signals.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/adapter-utils/src/cancellable-sandbox-command.test.ts

@@ -7,6 +7,23 @@ import { runAdapterExecutionTargetProcess } from "./execution-target.js";
 import { beginAdapterRunCancellation, cancelAdapterRunExecution, finishAdapterRunCancellation } from "./adapter-run-cancellation.js";
 
 describe("sandbox CLI cancellation through the execution target", () => {
+  it.each(["SIGTERM", "SIGKILL"] as const)("preserves a child's external %s termination", async (signal) => {
+    const runId = randomUUID();
+    beginAdapterRunCancellation(runId);
+    const runner: CommandManagedRuntimeRunner = { execute: async (input) => new Promise((resolve, reject) => {
+      const child = spawn(input.command === "node" ? process.execPath : input.command, input.args ?? [], { stdio: "ignore" });
+      child.once("error", reject);
+      child.once("close", (exitCode, signal) => resolve({ exitCode, signal, stdout: "", stderr: "", timedOut: false, pid: child.pid ?? null, startedAt: null }));
+    }) };
+    try {
+      const result = await executeCancellableSandboxCommand(runId, runner, {
+        command: process.execPath, args: ["-e", `process.kill(process.pid, '${signal}')`],
+      }, 100);
+      expect(result.signal).toBe(signal);
+      expect(result.exitCode).toBeNull();
+    } finally { finishAdapterRunCancellation(runId); }
+  });
+
   it("retains a failed cancellation for an explicit retry", async () => {
     const runId = randomUUID();
     beginAdapterRunCancellation(runId);

packages/adapter-utils/src/cancellable-sandbox-command.ts

@@ -32,11 +32,18 @@ const poll = setInterval(() => { if (cancelled()) stop(); }, 100);
 for (const name of ['SIGTERM', 'SIGINT', 'SIGHUP']) process.on(name, stop);
 const cleanup = () => { clearInterval(poll); clearTimeout(escalation); try { fs.unlinkSync(marker); } catch (e) { if (e.code !== 'ENOENT') throw e; } };
 child.once('error', () => { exited = true; cleanup(); process.exitCode = 127; });
-child.once('exit', code => {
+child.once('exit', (code, childSignal) => {
   // Do not leave a shell/tool child holding the provider's output pipe after
   // the CLI exits in response to cancellation. Never retain a PID kill timer.
   if (stopping) signal('SIGKILL');
-  exited = true; cleanup(); process.exitCode = stopping ? 143 : (code ?? 128);
+  exited = true; cleanup();
+  if (!stopping && childSignal) {
+    // Preserve the real termination signal instead of reporting exit code 128.
+    process.removeAllListeners(childSignal);
+    process.kill(process.pid, childSignal);
+    return;
+  }
+  process.exitCode = stopping ? 143 : (code ?? 1);
 });
 process.once('exit', () => { if (!exited) signal('SIGKILL'); });
 `;