redis-py Invalid Default Argument For LMPOP (Fix)

The Fix

pip install redis==7.1.0

Based on closed redis/redis-py issue #2414 · 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

@@ -2553,7 +2553,7 @@ def lmpop(
         num_keys: int,
         *args: List[str],
-        direction: str = None,
+        direction: str,
         count: Optional[int] = 1,

repro.py

>> redis.lmpop(1, "example")
Traceback (most recent call last):
  ...
  File "site-packages\redis\commands\core.py", line 2551, in lmpop
    return self.execute_command("LMPOP", *args)
  File "site-packages\redis\client.py", line 1238, in execute_command
    return conn.retry.call_with_retry(
  ...
  File "site-packages\redis\connection.py", line 108, in encode
    raise DataError(
redis.exceptions.DataError: Invalid input of type: 'NoneType'. Convert to a bytes, string, int or float first.

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: This fix should not be applied if the function requires a default behavior for direction.\n\n

Why This Fix Works in Production

Trigger: >> redis.lmpop(1, "example")
Mechanism: The LMPOP function had a default argument of None for direction, causing errors
Why the fix works: Removed the default None value from the LMPOP direction argument to prevent errors. (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

Shows up under Python 3.10 in real deployments (not just unit tests).
The LMPOP function had a default argument of None for direction, causing errors
Surfaces as: >> redis.lmpop(1, "example")

Proof / Evidence

GitHub issue: #2414
Fix PR: https://github.com/redis/redis-py/pull/2438
First fixed release: 7.1.0
Reproduced locally: No (not executed)
Last verified: 2026-02-07
Confidence: 0.95
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.47

Discussion

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

Jump to Sources Open on GitHub

“**Version**: Confirmed on redis-py 4.3.4, still in main. Redis 7.0.5 **Platform**: Python 3.10, Windows 10. Any OS and python version can reproduce. **Description**: The code for LMPOP gives the direction a default argument of None which is”

Issue thread · issue description · source

Failure Signature (Search String)

>> redis.lmpop(1, "example")

Error Message

Stack trace

error.txt

Error Message
-------------
>> redis.lmpop(1, "example")
Traceback (most recent call last):
  ...
  File "site-packages\redis\commands\core.py", line 2551, in lmpop
    return self.execute_command("LMPOP", *args)
  File "site-packages\redis\client.py", line 1238, in execute_command
    return conn.retry.call_with_retry(
  ...
  File "site-packages\redis\connection.py", line 108, in encode
    raise DataError(
redis.exceptions.DataError: Invalid input of type: 'NoneType'. Convert to a bytes, string, int or float first.

Minimal Reproduction

repro.py

>> redis.lmpop(1, "example")
Traceback (most recent call last):
  ...
  File "site-packages\redis\commands\core.py", line 2551, in lmpop
    return self.execute_command("LMPOP", *args)
  File "site-packages\redis\client.py", line 1238, in execute_command
    return conn.retry.call_with_retry(
  ...
  File "site-packages\redis\connection.py", line 108, in encode
    raise DataError(
redis.exceptions.DataError: Invalid input of type: 'NoneType'. Convert to a bytes, string, int or float first.

Environment

Python: 3.10

What Broke

Users experienced errors when calling LMPOP without specifying a valid direction.

Why It Broke

The LMPOP function had a default argument of None for direction, causing errors

Fix Options (Details)

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

pip install redis==7.1.0

When NOT to use: This fix should not be applied if the function requires a default behavior for direction.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/redis/redis-py/pull/2438

First fixed release: 7.1.0

Last verified: 2026-02-07. Validate in your environment.

When NOT to Use This Fix

This fix should not be applied if the function requires a default behavior for direction.

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.