redis-py Adding required `message` to `LockError` broke

The Fix

pip install redis==7.1.0

Based on closed redis/redis-py issue #3168 · 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%.

Jump to Verify Open PR/Commit

@@ -82,7 +82,7 @@ class LockError(RedisError, ValueError):
     # This was originally chosen to behave like threading.Lock.
 
-    def __init__(self, message, lock_name=None):
+    def __init__(self, message=None, lock_name=None):
         self.message = message

repro.py

from redis.exceptions import LockError
try:
    raise LockError()
except LockError:
    print("LockError raised")

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 redis==7.1.0\nWhen NOT to use: Do not use this fix if your application relies on the previous behavior of LockError without a message.\n\n

Why This Fix Works in Production

Trigger: TypeError: LockError.__init__() missing 1 required positional argument: 'message'
Mechanism: The introduction of a required 'message' parameter in LockError's __init__ method broke existing code that raised LockError without it
Why the fix works: Makes the 'message' parameter in LockError optional to support backwards compatibility. (first fixed release: 7.1.0).

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 introduction of a required 'message' parameter in LockError's __init__ method broke existing code that raised LockError without it
Surfaces as: TypeError: LockError.__init__() missing 1 required positional argument: 'message'

Proof / Evidence

GitHub issue: #3168
Fix PR: https://github.com/redis/redis-py/pull/3176
First fixed release: 7.1.0
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.74

Verified Execution

We executed the runnable minimal repro in a temporary environment and captured exit codes + logs.

Status: PASS
Ran: 2026-02-11T16:52:29Z
Package: redis
Fixed: 7.1.0
Mode: fixed_only
Outcome: ok

Logs

affected (exit=None)

fixed (exit=0)

LockError raised

Discussion

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

Jump to Sources Open on GitHub

“Resolved by https://github.com/redis/redis-py/pull/3176”

@miketheman · 2024-03-21 · confirmation · source

Failure Signature (Search String)

TypeError: LockError.__init__() missing 1 required positional argument: 'message'

Error Message

Stack trace

error.txt

Error Message
-------------
TypeError: LockError.__init__() missing 1 required positional argument: 'message'

Minimal Reproduction

repro.py

from redis.exceptions import LockError
try:
    raise LockError()
except LockError:
    print("LockError raised")

What Broke

Existing code raising LockError without a message fails, causing application errors.

Why It Broke

The introduction of a required 'message' parameter in LockError's __init__ method broke existing code that raised LockError without it

Fix Options (Details)

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

pip install redis==7.1.0

When NOT to use: Do not use this fix if your application relies on the previous behavior of LockError without a message.

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/redis/redis-py/pull/3176

First fixed release: 7.1.0

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

When NOT to Use This Fix

Do not use this fix if your application relies on the previous behavior of LockError without a message.
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

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
7.1.0	Fixed

Related Issues

No related fixes found.

Cluster: redis-py:configuration-error redis-py hub redis-py best practices All hubs All clusters

Related clusters: Retry storm Data consistency Race condition

Sources

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

redis-py Adding required `message` to `LockError` broke backwards compatibility (Fix)