Celery 5.3.2/3 has BREAKING change on EagerResult (Fix)

The Fix

pip install celery==5.3.5

Based on closed celery/celery issue #8472 · 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.

Jump to Verify Open PR/Commit

@@ -788,6 +788,7 @@ def apply(self, args=None, kwargs=None,
         request = {
             'id': task_id,
+            'task': self.name,
             'retries': retries,
             'is_eager': True,

repro

this bug.

verify

Follow the reproduction steps, confirm the failure, apply the fix, and repeat the same steps to verify the behavior changes.

fix.md

Option A — Upgrade to fixed release\npip install celery==5.3.5\nWhen NOT to use: This fix should not be used if the application relies on the previous behavior of EagerResult.\n\n

Why This Fix Works in Production

Trigger: 5.3.2/3 has BREAKING change on EagerResult
Mechanism: Fixes a breaking change introduced in a previous patch by ensuring that EagerResult objects correctly populate the task name field.
Why the fix works: Fixes a breaking change introduced in a previous patch by ensuring that EagerResult objects correctly populate the task name field. (first fixed release: 5.3.5).

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

Production symptom (often without a traceback): 5.3.2/3 has BREAKING change on EagerResult

Proof / Evidence

GitHub issue: #8472
Fix PR: https://github.com/celery/celery/pull/8486
First fixed release: 5.3.5
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.75
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.78

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“@KOliver94 i do create EagerResult in the code. i dont see it cropping up without code paths that hit that. however my concern is not…”

@benconnito · 2023-09-05 · confirmation · source

“Please yank the faulty versions from Pypi. This is just the last 15 minutes since I updated from 5.3.1 to 5.3.3 !image”

@ppfeufer · 2023-09-01 · source

“I am going to yank or delete both of the release for now”

@auvipy · 2023-09-02 · source

“@benconnito @ppfeufer can you help me if the only issue is the breaking change in the constructor for a patch version because you create EagerResult…”

@KOliver94 · 2023-09-04 · source

Failure Signature (Search String)

5.3.2/3 has BREAKING change on EagerResult
- [ ] I have included all related issues and possible duplicate issues

Copy-friendly signature

signature.txt

Failure Signature
-----------------
5.3.2/3 has BREAKING change on EagerResult
- [ ] I have included all related issues and possible duplicate issues

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
5.3.2/3 has BREAKING change on EagerResult
- [ ] I have included all related issues and possible duplicate issues

Minimal Reproduction

this bug.

What Broke

Users experienced TypeError exceptions when using EagerResult in production environments.

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install celery==5.3.5

When NOT to use: This fix should not be used if the application relies on the previous behavior of EagerResult.

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)

onceonly.py

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)

See OnceOnly SDK

When NOT to use: 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.

Fix reference: https://github.com/celery/celery/pull/8486

First fixed release: 5.3.5

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

This fix should not be used if the application relies on the previous behavior of EagerResult.
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

verify

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
5.3.5	Fixed

Related Issues

No related fixes found.

Cluster: celery:configuration-error Celery hub Celery best practices All hubs All clusters

Related clusters: Data consistency Duplicates Duplicate processing

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.