Celery Redis connection timeouts are not coerced correctly

The Fix

pip install celery==4.4.0rc5

Based on closed celery/celery issue #4735 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Open PR/Commit

@@ -29,6 +29,7 @@
 try:
     import redis
+    import redis.connection
     from kombu.transport.redis import get_redis_error_classes
 except ImportError:  # pragma: no cover

fix.md

Option A — Upgrade to fixed release\npip install celery==4.4.0rc5\nWhen NOT to use: Do not apply this fix if using a Redis version that does not support coercion.\n\n

Why This Fix Works in Production

Trigger: Redis connection timeouts are not coerced correctly
Mechanism: Celery incorrectly passes timeout values as strings instead of floats to the Redis client
Why the fix works: Uses Redis's coercion mechanism for converting query parameters, ensuring that timeouts specified in the result backend URL are correctly interpreted as floats. (first fixed release: 4.4.0rc5).

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

Celery incorrectly passes timeout values as strings instead of floats to the Redis client
Production symptom (often without a traceback): Redis connection timeouts are not coerced correctly

Proof / Evidence

GitHub issue: #4735
Fix PR: https://github.com/celery/celery/pull/4736
First fixed release: 4.4.0rc5
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.78

Discussion

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

Jump to Sources Open on GitHub

“Found using celery 4.1.0. ## Steps to reproduce Configure with redis as a backend with timeouts set in the url: ## Expected behavior Timeouts are applied and celery works normally. ## Actual behavior Errors are raised by the socket library”

Issue thread · issue description · source

Failure Signature (Search String)

Redis connection timeouts are not coerced correctly
Configure with redis as a backend with timeouts set in the url:

Copy-friendly signature

signature.txt

Failure Signature
-----------------
Redis connection timeouts are not coerced correctly
Configure with redis as a backend with timeouts set in the url:

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
Redis connection timeouts are not coerced correctly
Configure with redis as a backend with timeouts set in the url:

What Broke

Redis connection timeouts lead to socket errors and application failures.

Why It Broke

Celery incorrectly passes timeout values as strings instead of floats to the Redis client

Fix Options (Details)

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

pip install celery==4.4.0rc5

When NOT to use: Do not apply this fix if using a Redis version that does not support coercion.

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/4736

First fixed release: 4.4.0rc5

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

When NOT to Use This Fix

Do not apply this fix if using a Redis version that does not support coercion.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Make timeouts explicit and test them (unit + integration) to avoid silent behavior changes.
Instrument retries (attempt count + reason) and alert on spikes to catch dependency slowdowns.

Version Compatibility Table

Version	Status
4.4.0rc5	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.

Celery Redis connection timeouts are not coerced correctly (Fix)