redis-py LMOVE, BLMOVE return incorrect response (Fix)

The Fix

pip install redis==7.1.0

Based on closed redis/redis-py issue #1776 · 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

@@ -658,8 +658,8 @@ class Redis(RedisModuleCommands, CoreCommands, SentinelCommands):
         **string_keys_to_dict(
             "AUTH COPY EXPIRE EXPIREAT PEXPIRE PEXPIREAT "
-            "HEXISTS HMSET LMOVE BLMOVE MOVE "
-            "MSETNX PERSIST PSETEX RENAMENX SISMEMBER SMOVE SETEX SETNX",
+            "HEXISTS HMSET MOVE MSETNX PERSIST "

repro.py

lmove x x LEFT RIGHT
"abc"

blmove x x LEFT RIGHT 1
"abc"

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 boolean response is intended for a different context.\n\n

Why This Fix Works in Production

Trigger: LMOVE, BLMOVE return incorrect response
Mechanism: The LMOVE and BLMOVE methods incorrectly returned a boolean instead of the expected value
Why the fix works: Fixes the incorrect response returned by LMOVE and BLMOVE in redis-py by removing them from the RESPONSE_CALLBACKS. (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 LMOVE and BLMOVE methods incorrectly returned a boolean instead of the expected value
Production symptom (often without a traceback): LMOVE, BLMOVE return incorrect response

Proof / Evidence

GitHub issue: #1776
Fix PR: https://github.com/redis/redis-py/pull/1906
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: 0.69

Discussion

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

Jump to Sources Open on GitHub

“@varunchopra Thank you! By all means, I'd love to see that :). At the same time, please notice that BLMOVE returns a Bulk string or…”

@chayim · 2021-12-08 · source

“> At the same time, please notice that BLMOVE returns a Bulk string or a Null reply whereas LMOVE returns a bulk string”

@varunchopra · 2021-12-11 · source

“@varunchopra Apologies, apparently I wasn't clear. You are correct. That removal ought solve this issue.”

@chayim · 2021-12-12 · source

Failure Signature (Search String)

LMOVE, BLMOVE return incorrect response
>> r.blmove('x', 'x', timeout=1)

Copy-friendly signature

signature.txt

Failure Signature
-----------------
LMOVE, BLMOVE return incorrect response
>> r.blmove('x', 'x', timeout=1)

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
LMOVE, BLMOVE return incorrect response
>> r.blmove('x', 'x', timeout=1)

Minimal Reproduction

repro.py

lmove x x LEFT RIGHT
"abc"

blmove x x LEFT RIGHT 1
"abc"

What Broke

Users received incorrect boolean responses instead of the expected values from LMOVE and BLMOVE.

Why It Broke

The LMOVE and BLMOVE methods incorrectly returned a boolean instead of the expected value

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 boolean response is intended for a different context.

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/1906

First fixed release: 7.1.0

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

When NOT to Use This Fix

This fix should not be applied if the boolean response is intended for a different context.

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

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
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.