The Fix
pip install celery==5.5.0
Based on closed celery/celery issue #9119 · 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.
@@ -54,6 +54,9 @@ def _boundmethod_safe_weakref(obj):
if dispatch_uid:
return (dispatch_uid, _make_id(sender))
+ # Issue #9119 - retry-wrapped functions use the underlying function for dispatch_uid
+ elif hasattr(receiver, '_dispatch_uid'):
+ return (receiver._dispatch_uid, _make_id(sender))
this bug.
Follow the reproduction steps, confirm the failure, apply the fix, and repeat the same steps to verify the behavior changes.
Option A — Upgrade to fixed release\npip install celery==5.5.0\nWhen NOT to use: This fix should not be used if the signal receiver does not utilize retry-wrapping.\n\n
Why This Fix Works in Production
- Trigger: Cannot disconnect a signal receiver after using Signal.connect(retry=True)
- Mechanism: Retry-wrapped functions do not use the correct dispatch_uid for disconnection
- Why the fix works: Addresses issue #9119 by injecting the dispatch_uid for retry-wrapped receivers, allowing for proper disconnection of signal receivers. (first fixed release: 5.5.0).
- If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.
Why This Breaks in Prod
- Retry-wrapped functions do not use the correct dispatch_uid for disconnection
- Production symptom (often without a traceback): Cannot disconnect a signal receiver after using Signal.connect(retry=True)
Proof / Evidence
- GitHub issue: #9119
- Fix PR: https://github.com/celery/celery/pull/9247
- First fixed release: 5.5.0
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.85
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.73
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“> I've planned to create a PR with a failing test case I now have a failing unit test in a branch, but some time…”
“I opened a small PR, but need some guidance as to whether this approach is desirable or not”
Failure Signature (Search String)
- Cannot disconnect a signal receiver after using Signal.connect(retry=True)
- - [x] I have included all related issues and possible duplicate issues
Copy-friendly signature
Failure Signature
-----------------
Cannot disconnect a signal receiver after using Signal.connect(retry=True)
- [x] I have included all related issues and possible duplicate issues
Error Message
Signature-only (no traceback captured)
Error Message
-------------
Cannot disconnect a signal receiver after using Signal.connect(retry=True)
- [x] I have included all related issues and possible duplicate issues
Minimal Reproduction
- this bug.
What Broke
Signal receivers cannot be properly disconnected, leading to unexpected behavior.
Why It Broke
Retry-wrapped functions do not use the correct dispatch_uid for disconnection
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==5.5.0
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/9247
First fixed release: 5.5.0
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix should not be used if the signal receiver does not utilize retry-wrapping.
- 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.
Verify Fix
Follow the reproduction steps, confirm the failure, apply the fix, and repeat the same steps to verify the behavior changes.
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 |
|---|---|
| 5.5.0 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.