The Fix
pip install celery==5.4.0
Based on closed celery/celery issue #8822 · PR/commit linked
Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.
@@ -17,7 +17,9 @@ on:
# The branches below must be a subset of the branches above
branches: [ main ]
-
+ workflow_dispatch:
+
Option A — Upgrade to fixed release\npip install celery==5.4.0\nWhen NOT to use: This fix is not suitable for workflows that should not be manually triggered.\n\n
Why This Fix Works in Production
- Trigger: - [x] I have included all related issues and possible duplicate issues in this issue
- Mechanism: The CI lacked the workflow_dispatch event for manual workflow triggering
- Why the fix works: Adds the `workflow_dispatch` event to the CI, allowing developers to trigger workflows manually for debugging and testing purposes. (first fixed release: 5.4.0).
Why This Breaks in Prod
- The CI lacked the workflow_dispatch event for manual workflow triggering
- Production symptom (often without a traceback): - [x] I have included all related issues and possible duplicate issues in this issue
Proof / Evidence
- GitHub issue: #8822
- Fix PR: https://github.com/celery/celery/pull/8826
- First fixed release: 5.4.0
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.85
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.82
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“<!-- Please fill this template entirely and do not erase parts of it. We reserve the right to close without a response enhancement requests which are incomplete. --> # Checklist <!-- To check an item on the list replace [ ] with [x]. --> -”
Failure Signature (Search String)
- - [x] I have included all related issues and possible duplicate issues in this issue
- * No UI changes are directly associated with this proposal.
Copy-friendly signature
Failure Signature
-----------------
- [x] I have included all related issues and possible duplicate issues in this issue
* No UI changes are directly associated with this proposal.
Error Message
Signature-only (no traceback captured)
Error Message
-------------
- [x] I have included all related issues and possible duplicate issues in this issue
* No UI changes are directly associated with this proposal.
What Broke
Developers faced challenges in debugging workflows due to lack of manual control.
Why It Broke
The CI lacked the workflow_dispatch event for manual workflow triggering
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==5.4.0
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Option D — Guard side-effects with OnceOnly Guardrail for side-effects
Mitigate duplicate external side-effects under retries/timeouts/agent loops by gating the operation before calling external systems.
- Place OnceOnly between your code/agent and real side-effects (Stripe, emails, CRM, APIs).
- Use a stable key per side-effect (e.g., customer_id + action + idempotency_key).
- Fail-safe: configure fail-open vs fail-closed based on blast radius and spend risk.
Show example snippet (optional)
from onceonly import OnceOnly
import os
once = OnceOnly(api_key=os.environ["ONCEONLY_API_KEY"], fail_open=True)
# Stable idempotency key per real side-effect.
# Use a request id / job id / webhook delivery id / Stripe event id, etc.
event_id = "evt_..." # replace
key = f"stripe:webhook:{event_id}"
res = once.check_lock(key=key, ttl=3600)
if res.duplicate:
return {"status": "already_processed"}
# Safe to execute the side-effect exactly once.
handle_event(event_id)
Fix reference: https://github.com/celery/celery/pull/8826
First fixed release: 5.4.0
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix is not suitable for workflows that should not be manually triggered.
- Do not use this to hide logic bugs or data corruption. Use it to block duplicate external side-effects and enforce tool permissions/spend caps.
Did This Fix Work in Your Case?
Quick signal helps us prioritize which fixes to verify and improve.
Prevention
- Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
- Pin production dependencies and upgrade only with a reproducible test that hits the failing path.
Version Compatibility Table
| Version | Status |
|---|---|
| 5.4.0 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.