Modal exhausted-task recovery retry rejects validated workflow relocation

Generic reproduction: relocated Modal retry omits durability acknowledgement

Captured: 2026-08-21T19:14:05Z

UltraFuzz release base: 9b0bc8cab2e681bbffeee385c1f80f85a47087d3

Affected surface: the release's Modal node worker recovery for a generic external Solidity target. No target identity, prompt, source path, business logic, or finding is included here.

Preconditions

1. A Modal node has a persisted inner workflow run under the worker's durable workspace.
2. Callback termination has exhausted the selected inner task's attempts.
3. A later worker resumes the same durable workspace through UltraFuzz's supported outer retry path.
4. The worker presents the immutable workflow from its validated relocated snapshot path, so the inner runtime observes the expected workflow-path/module-root/VCS-root relocation.

Minimal release-owned check

Run against the built release helper:

import { workflowRetryTaskCommandArguments } from "./packages/modal/dist/node-worker.js";

const args = workflowRetryTaskCommandArguments(
  "/durable/relocated-workflow.tsx",
  "generic-external-run",
  "node:analysis"
);

if (!args.includes("--accept-workflow-change")) process.exit(1);

Observed output on the affected worker:

{"command":"retry-task","has_accept_workflow_change":false,"uses_force":true,"node_scoped":true}

Observed exit code: 1.

The preceding ordinary resume is intentionally conservative. Once its exact-task diagnosis reports retries-exhausted, however, the worker invokes retry-task without --accept-workflow-change. The bundled runtime rejects the retry with RETRY_TASK_FAILED and reports that workflow path, module graph, and VCS root changed, explicitly requiring --accept-workflow-change to re-bless this run in place.

Expected

The narrowly gated exact-task recovery should acknowledge the worker-owned, already-validated relocation when invoking retry-task, while leaving ordinary resume, missing-run fallback, and unrelated failures unchanged.

Start in packages/modal/dist/node-worker.js and trace workflowRetryTaskCommandArguments, then inspect the exact-task retries-exhausted recovery path. Run the supplied release-helper check against the relocated workflow arguments; done means that narrowly gated retry includes --accept-workflow-change while ordinary resume, missing-run fallback, and unrelated failures remain unchanged.