The Fix
pip install celery==5.5.0
Based on closed celery/celery issue #8976 · 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.
@@ -12,10 +12,10 @@ class DjangoTask(Task):
"""
- def delay_on_commit(self, *args, **kwargs):
+ def delay_on_commit(self, *args, **kwargs) -> None:
"""Call :meth:`~celery.app.task.Task.delay` with Django's ``on_commit()``."""
repro.py
class DjangoTask(Task):
"""
Extend the base :class:`~celery.app.task.Task` for Django.
Provide a nicer API to trigger tasks at the end of the DB transaction.
"""
def delay_on_commit(self, *args, **kwargs):
"""Call :meth:`~celery.app.task.Task.delay` with Django's ``on_commit()``."""
return transaction.on_commit(functools.partial(self.delay, *args, **kwargs))
def apply_async_on_commit(self, *args, **kwargs):
"""Call :meth:`~celery.app.task.Task.apply_async` with Django's ``on_commit()``."""
return transaction.on_commit(functools.partial(self.apply_async, *args, **kwargs))
verify
Re-run the minimal reproduction on your broken version, then apply the fix and re-run.
fix.md
Option A — Upgrade to fixed release\npip install celery==5.5.0\nWhen NOT to use: Do not use delay_on_commit if you need the task UUID immediately.\n\n
Why This Fix Works in Production
- Trigger: - [ ] I have included all related issues and possible duplicate issues
- Mechanism: The delay_on_commit method was incorrectly returning None instead of the task UUID
- Why the fix works: Clarifies the return values for the delay_on_commit and apply_async_on_commit methods, ensuring they return None instead of a task UUID. (first fixed release: 5.5.0).
Production impact:
- If left unfixed, retries/timeouts can trigger duplicate external side-effects (double charges, duplicate emails, repeated writes).
Why This Breaks in Prod
- The delay_on_commit method was incorrectly returning None instead of the task UUID
- Production symptom (often without a traceback): - [ ] I have included all related issues and possible duplicate issues
Proof / Evidence
- GitHub issue: #8976
- Fix PR: https://github.com/celery/celery/pull/8984
- 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: 0.52
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“> > [x] I have tried to reproduce the issue with pytest-celery and added the reproduction script below. > > Where is it? oh no…”
“> [x] I have tried to reproduce the issue with pytest-celery and added the reproduction script below. Where is it?”
“> so if I need the task UUID just use mandatory the delay or apply_async call task method, correctly? Correct, yes”
“I think that django transaction.on_commit should return None, but this is the source of django transaction,py transaction.py if use the decorator instead the on_commit function?…”
Failure Signature (Search String)
- - [ ] I have included all related issues and possible duplicate issues
- or possible duplicates to this issue as requested by the checklist above.
Copy-friendly signature
signature.txt
Failure Signature
-----------------
- [ ] I have included all related issues and possible duplicate issues
or possible duplicates to this issue as requested by the checklist above.
Error Message
Signature-only (no traceback captured)
error.txt
Error Message
-------------
- [ ] I have included all related issues and possible duplicate issues
or possible duplicates to this issue as requested by the checklist above.
Minimal Reproduction
repro.py
class DjangoTask(Task):
"""
Extend the base :class:`~celery.app.task.Task` for Django.
Provide a nicer API to trigger tasks at the end of the DB transaction.
"""
def delay_on_commit(self, *args, **kwargs):
"""Call :meth:`~celery.app.task.Task.delay` with Django's ``on_commit()``."""
return transaction.on_commit(functools.partial(self.delay, *args, **kwargs))
def apply_async_on_commit(self, *args, **kwargs):
"""Call :meth:`~celery.app.task.Task.apply_async` with Django's ``on_commit()``."""
return transaction.on_commit(functools.partial(self.apply_async, *args, **kwargs))
What Broke
Users were unable to retrieve task UUIDs when using delay_on_commit, leading to confusion.
Why It Broke
The delay_on_commit method was incorrectly returning None instead of the task UUID
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==5.5.0
When NOT to use: Do not use delay_on_commit if you need the task UUID immediately.
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/celery/celery/pull/8984
First fixed release: 5.5.0
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- Do not use delay_on_commit if you need the task UUID immediately.
Verify Fix
verify
Re-run the minimal reproduction on your broken version, then apply the fix and re-run.
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.