The Fix
pip install celery==5.1.0b1
Based on closed celery/celery issue #6476 · 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.
@@ -279,3 +279,4 @@ Sardorbek Imomaliev, 2020/01/24
Frazer McLean, 2020/09/29
Henrik Bruåsdal, 2020/11/29
+Tom Wojcik, 2021/01/24
diff --git a/celery/app/defaults.py b/celery/app/defaults.py
index 9fec8472c96..51e1e2f96c1 100644
repro.py
import pytest
@pytest.mark.parametrize(
"eager,ignore_result,publish_result",
[
(True, True, False),
(True, False, True), # fails
(False, True, False),
(False, False, True),
]
)
def test_publish_result_current(eager, ignore_result, publish_result):
actual_publish_result = not eager and not ignore_result
assert publish_result == actual_publish_result
@pytest.mark.parametrize(
"eager,ignore_result,publish_result",
[
(True, True, False),
(True, False, True),
(False, True, False),
(False, False, True),
]
)
def test_publish_result_desired(eager, ignore_result, publish_result):
actual_publish_result = not ignore_result
assert publish_result == actual_publish_result
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==5.1.0b1\nWhen NOT to use: This fix should not be used if existing behavior of eager tasks is relied upon in production.\n\n
Why This Fix Works in Production
- Trigger: Currently published version doesn't support Celery 5.x, but all versions are affected
- Mechanism: The eager task execution does not save results when ignore_result is set to False
- Why the fix works: Adds a setting that allows eager tasks to store their results on the backend, addressing the issue where results are not saved when tasks are executed eagerly and results are not ignored. (first fixed release: 5.1.0b1).
Production impact:
- 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
- The eager task execution does not save results when ignore_result is set to False
- Production symptom (often without a traceback): Currently published version doesn't support Celery 5.x, but all versions are affected
Proof / Evidence
- GitHub issue: #6476
- Fix PR: https://github.com/celery/celery/pull/6614
- First fixed release: 5.1.0b1
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.85
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.51
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“did you try the latest release & share your feedback?”
“it would be great if you can share a possible solution”
“I tried the latest release”
“Yes @auvipy . I already tried to fix this but some tests started to fail due to some side effects but I think some are…”
Failure Signature (Search String)
- Currently published version doesn't support Celery 5.x, but all versions are affected
- https://github.com/celery/celery/blob/2a6c7cfe3b1283961887bf1cb3f5aa6c8aa70820/celery/app/trace.py#L323
Copy-friendly signature
signature.txt
Failure Signature
-----------------
Currently published version doesn't support Celery 5.x, but all versions are affected
https://github.com/celery/celery/blob/2a6c7cfe3b1283961887bf1cb3f5aa6c8aa70820/celery/app/trace.py#L323
Error Message
Signature-only (no traceback captured)
error.txt
Error Message
-------------
Currently published version doesn't support Celery 5.x, but all versions are affected
https://github.com/celery/celery/blob/2a6c7cfe3b1283961887bf1cb3f5aa6c8aa70820/celery/app/trace.py#L323
Minimal Reproduction
repro.py
import pytest
@pytest.mark.parametrize(
"eager,ignore_result,publish_result",
[
(True, True, False),
(True, False, True), # fails
(False, True, False),
(False, False, True),
]
)
def test_publish_result_current(eager, ignore_result, publish_result):
actual_publish_result = not eager and not ignore_result
assert publish_result == actual_publish_result
@pytest.mark.parametrize(
"eager,ignore_result,publish_result",
[
(True, True, False),
(True, False, True),
(False, True, False),
(False, False, True),
]
)
def test_publish_result_desired(eager, ignore_result, publish_result):
actual_publish_result = not ignore_result
assert publish_result == actual_publish_result
What Broke
Tasks executed eagerly do not store results, leading to missing data in the backend.
Why It Broke
The eager task execution does not save results when ignore_result is set to False
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==5.1.0b1
When NOT to use: This fix should not be used if existing behavior of eager tasks is relied upon in production.
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/6614
First fixed release: 5.1.0b1
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- This fix should not be used if existing behavior of eager tasks is relied upon in production.
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 |
|---|---|
| 5.1.0b1 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.