Seeking guidance for `hiredis` dependency on `redis-py`

[ramchandra-st]

I have a question regarding the hiredis dependency in redis-py.
Is hiredis a required dependency for using the package, or is it optional?

I have an implicit dependency on redis-py and I've encountered an issue with a locked version of hiredis in my requirements.txt

Since redis-py updates automatically as it is implicit, it can lead to a version mismatch where redis-py is updated, but hiredis remains locked to an older version, causing an unsynchronized state.

Could you provide guidance on how to handle this situation and avoid any conflicts arising from the version lock?

[ramchandra-st]

I noticed that in the recent redis-py update (5.1.0), the author forgot to mention the hiredis dependency, although it is mentioned here:

Including such a change in the release log would be quite helpful for other developers.

[ramchandra-st]

So I request to add this information on release notes of 5.1.0 :)

[dmaier-redislabs]

Hi @ramchandra-st,

it's possible to use redis-py without hiredis, but if hiredis is installed, then redis-py will use it. This is documented in the README here on Github.

Which version of hiredis are you using?

Regards,
David

[helissonomc]

Hey guys, i created this issue #3393 about it, i just realised that this is talking about this same issue, should i close it?

[dmaier-redislabs]

@helissonomc Yes, please. Can you add any relevant detail here please.

[helissonomc]

With version 5.1.0 I started to face the error message:
NameError: name 'hiredis' is not defined
The error was introduced by the code inside redis/utils.py

try:
    import hiredis  # noqa

    # Only support Hiredis >= 3.0:
    HIREDIS_AVAILABLE = int(hiredis.__version__.split(".")[0]) >= 3
    HIREDIS_PACK_AVAILABLE = hasattr(hiredis, "pack_command")
except ImportError:
    HIREDIS_AVAILABLE = False
    HIREDIS_PACK_AVAILABLE = False

If the hiredis version is lower than 3 (which mine is) the HIREDIS_AVAILABLE is going to be false, therefore it will keep giving error inside the redis/connection.py file, because the import hiredis will not be executed, but the code still relies on this import.

[ramchandra-st]

Yeah, problem presented by @helissonomc is same as what I want to highlight here.

Thanks folks for engagement here :)

[dmaier-redislabs]

OK, seems to be a bug that was introduced by trying to enforce hiredis >=3. We will take a look and fix it. Thanks for the detailed report.

[dmaier-redislabs]

Hi,

this bug could be reproduced with redis-py 5.1.0 and hiredis-py 2.4.0. The library redis-py should fall back to its internal response parser if the hiredis-py has a lower version than 3.0. There are two boolean variables checked and HIREDIS_PACK_AVAILABLE can be true if any version of hiredis-py is installed, which causes the bug. This will be fixed in a maintenance version. We apologize for the inconvenience.

Regards,
David