Celery Test failing in master for 4.4.0rc3 (Fix)

The Fix

pip install celery==4.4.0rc5

Based on closed celery/celery issue #5676 · 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

@@ -129,8 +129,9 @@ def test_init_mongodb_dns_seedlist(self, dns_resolver_query):
         self.app.conf.mongodb_backend_settings = None
 
-        def mock_resolver(_, record_type):
-            if record_type == 'SRV':
+        def mock_resolver(_, rdtype, rdclass=None, lifetime=None, **kwargs):

fix.md

Option A — Upgrade to fixed release\npip install celery==4.4.0rc5\nWhen NOT to use: Do not apply this fix if the mock_resolver function is expected to remain unchanged.\n\n

Why This Fix Works in Production

Trigger: E pymongo.errors.ConfigurationError: mock_resolver() got an unexpected keyword argument 'lifetime'
Mechanism: The mock_resolver function did not accept the 'lifetime' keyword argument, causing a ConfigurationError
Why the fix works: Fixes unit test test_MongoBackend.test_init_mongodb_dns_seedlist to handle unexpected keyword argument 'lifetime'. (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

The mock_resolver function did not accept the 'lifetime' keyword argument, causing a ConfigurationError
Surfaces as: E pymongo.errors.ConfigurationError: mock_resolver() got an unexpected keyword argument 'lifetime'

Proof / Evidence

GitHub issue: #5676
Fix PR: https://github.com/celery/celery/pull/5680
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: 0.71

Discussion

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

Jump to Sources Open on GitHub

“probably the commit to checking https://github.com/celery/kombu/commit/0ad7d08c4cb4abce32e9d765d0bb16b92830451f”

@auvipy · 2019-08-17 · source

Failure Signature (Search String)

E pymongo.errors.ConfigurationError: mock_resolver() got an unexpected keyword argument 'lifetime'

Error Message

Stack trace

error.txt

Error Message
-------------
E           pymongo.errors.ConfigurationError: mock_resolver() got an unexpected keyword argument 'lifetime'

What Broke

Unit tests for MongoDB backend failed due to unexpected keyword argument in mock resolver.

Why It Broke

The mock_resolver function did not accept the 'lifetime' keyword argument, causing a ConfigurationError

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 the mock_resolver function is expected to remain unchanged.

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/5680

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 the mock_resolver function is expected to remain unchanged.

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.