Issue with cache_config with 7.4.0

[QHivert]

Hello,

I was using 7.1.1 and after an update to 7.4.0, see this bug.

Here an example:

from redis import Redis,
from redis.cache import CacheConfig

conn_str =  "redis://username:password@redis:6379/?decode_responses=Yes&protocol=3"
redis = Redis.from_url(redis_connstring, cache_config=CacheConfig())

# Fill up a sorted set
redis.zadd("myset", {"foo": 1})
redis.zadd("myset", {"bar": 2})

#First time it works because redis actually do the command
total_count = redis.zcard("myset")

#Second time it raises an error because redis try to get the info from the cache instead of doing the command
total_count = redis.zcard("myset")

The exception raises:

 File "/workspace/app/manager/cache/ClientRedis.py", line 257, in zset_paginate_hashes
    total_count = redis.zcard(zset_key_default)
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/commands/core.py", line 4731, in zcard
    return self.execute_command("ZCARD", name, keys=[name])
           ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 716, in execute_command
    return self._execute_command(*args, **options)
           ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 736, in _execute_command
    result = conn.retry.call_with_retry(
    
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/retry.py", line 120, in call_with_retry
    return do()
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 737, in <lambda>
    lambda: self._send_command_parse_response(
    
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 682, in _send_command_parse_response
    return self.parse_response(conn, command_name, **options)
           ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 780, in parse_response
    response = connection.read_response()
  File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/connection.py", line 1715, in read_response
    bytes_saved=len(res)

The problem is in this function read_response ->

redis-py/redis/connection.py

Line 1716 in a8f9ab4

def read_response(

The first time:

• self._current_command_cache_key = CacheKey(command='ZCARD', redis_keys=('user_sessions:activity',), redis_args=('ZCARD', 'user_sessions:activity'))
• Not in self._cache so the command is done
• response = 2
• store in cache

Next time:

• self._current_command_cache_key = CacheKey(command='ZCARD', redis_keys=('user_sessions:activity',), redis_args=('ZCARD', 'user_sessions:activity'))
• In self._cache get the cache reponse
• res = 2
• after at line 1714: record_csc_network_saved(bytes_saved=len(res) ) -> crash because res is a int.

[nadiatazi262-tech]

After updating to 7.4.0, zcard fails on the second call because the cached response is an integer. The first call works, but record_csc_network_saved(len(res)) crashes since len() doesn’t accept ints. Seems like the cache layer needs to handle non-bytes results.

…

On Fri, Mar 27, 2026, 5:22 AM QHivert ***@***.***> wrote: *QHivert* created an issue (redis/redis-py#4009) <#4009> Hello, I was using 7.1.1 and after an update to 7.4.0, see this bug. Here an example: from redis import Redis,from redis.cache import CacheConfig conn_str = ***@***.***:6379/?decode_responses=Yes&protocol=3"redis = Redis.from_url(redis_connstring, cache_config=CacheConfig()) # Fill up a sorted setredis.zadd("myset", {"foo": 1})redis.zadd("myset", {"bar": 2}) #First time it works because redis actually do the commandtotal_count = redis.zcard("myset") #Second time it raises an error because redis try to get the info from the cache instead of doing the commandtotal_count = redis.zcard("myset") The exception raises: File "/workspace/app/manager/cache/ClientRedis.py", line 257, in zset_paginate_hashes total_count = redis.zcard(zset_key_default) File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/commands/core.py", line 4731, in zcard return self.execute_command("ZCARD", name, keys=[name]) ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 716, in execute_command return self._execute_command(*args, **options) ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^ File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 736, in _execute_command result = conn.retry.call_with_retry( File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/retry.py", line 120, in call_with_retry return do() File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 737, in <lambda> lambda: self._send_command_parse_response( File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 682, in _send_command_parse_response return self.parse_response(conn, command_name, **options) ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/client.py", line 780, in parse_response response = connection.read_response() File "/home/quentin/.cache/pypoetry/virtualenvs/sogo-xS3fZVNL-py3.13/lib/python3.13/site-packages/redis/connection.py", line 1715, in read_response bytes_saved=len(res) The problem is in this function read_response -> https://github.com/redis/redis-py/blob/a8f9ab419bcbebce3015fe24ae4ab16366c7bfcd/redis/connection.py#L1716 The first time: - self._current_command_cache_key = CacheKey(command='ZCARD', redis_keys=('user_sessions:activity',), redis_args=('ZCARD', 'user_sessions:activity')) - Not in self._cache so the command is done - response = 2 - store in cache Next time: - self._current_command_cache_key = CacheKey(command='ZCARD', redis_keys=('user_sessions:activity',), redis_args=('ZCARD', 'user_sessions:activity')) - In self._cache get the cache reponse - res = 2 - after at line 1714: record_csc_network_saved(bytes_saved=len(res) ) -> crash because res is a int. — Reply to this email directly, view it on GitHub <#4009?email_source=notifications&email_token=B7HY733GSUIJT7MEWGUKT434SZI7JA5CNFSL4Z3JMQ5C6L3HNF2C22DVMIXUS43TOVSS6NBRGUYTGMZWHA3TFJTSMVQXG33OVJZXKYTTMNZGSYTFMSSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7HY737M3K7BCOGSSIQZ7QL4SZI7JAVCNFSM6AAAAACXBXOUSSVHI2DSMVQWIX3LMV43ASLTON2WKOZUGE2TCMZTGY4DOMQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[petyaslavova]

Hi @QHivert, thank you for reporting this! We will have a look at it!

[arlosnow1231-stack]

Thanks for bringing this up

…

On Fri, Mar 27, 2026, 12:39 PM petyaslavova ***@***.***> wrote: *petyaslavova* left a comment (redis/redis-py#4009) <#4009 (comment)> Hi @QHivert <https://github.com/QHivert>, thank you for reporting this! We will have a look at it! — Reply to this email directly, view it on GitHub <#4009?email_source=notifications&email_token=CAXLFZXK3MWGXTDQQCGJI634S24D7A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTIMJUGQZDANZSG442M4TFMFZW63VKON2WE43DOJUWEZLEUVSXMZLOOSWGM33PORSXEX3DNRUWG2Y#issuecomment-4144207279>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/CAXLFZR4CHDGGLUXHX32ZZT4S24D7AVCNFSM6AAAAACXBXOUSSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DCNBUGIYDOMRXHE> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>