#33361: Redis cache backend doesn't allow storing bool values
-------------------------------------+------------------------------------
Reporter: Jeremy Lainé | Owner: nobody
Type: Bug | Status: new
Component: Core (Cache system) | Version: 4.0
Severity: Release blocker | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by Mariusz Felisiak):
* cc: Nick Pope, Daniyal Abbasi (added)
* stage: Unreviewed => Accepted
* severity: Normal => Release blocker
Old description:
> The following code raises an exception: `redis.exceptions.DataError:
> Invalid input of type: 'bool'. Convert to a bytes, string, int or float
> first.`
>
> {{{#!python
> from django.core.cache import cache
> cache.set("foo", True)
> }}}
>
> This contradicts the documentation which states that any data type
> supported by pickle can be stored to the cache.
>
> The root cause seems to be because instances of `int` are special-cased
> and not send through pickle, but redis-py cannot send booleans to redis:
>
> https://github.com/django/django/blob/2f73e5406d54cb8945e187eff302a3a3373350be/django/core/cache/backends/redis.py#L14
>
> What was the rationale behind the `int` special-case? `django-redis` for
> instance consistently sends all data through pickle.
New description:
The following code raises an exception: `redis.exceptions.DataError:
Invalid input of type: 'bool'. Convert to a bytes, string, int or float
first.`
{{{#!python
from django.core.cache import cache
cache.set("foo", True)
}}}
This contradicts the documentation which states that any data type
supported by pickle can be stored to the cache.
The root cause seems to be because instances of `int` are special-cased
and not send through pickle, but redis-py cannot send booleans to redis:
https://github.com/django/django/blob/2f73e5406d54cb8945e187eff302a3a3373350be/django/core/cache/backends/redis.py#L14
What was the rationale behind the `int` special-case? `django-redis` for
instance consistently sends all data through pickle.
--
Comment:
Thanks for report! It should be enough to special-case `bool`, e.g.
{{{#!diff
diff --git a/django/core/cache/backends/redis.py
b/django/core/cache/backends/redis.py
index 16556b1ded..bbb0e0320d 100644
--- a/django/core/cache/backends/redis.py
+++ b/django/core/cache/backends/redis.py
@@ -11,7 +11,7 @@ from django.utils.module_loading import import_string
class RedisSerializer(PickleSerializer):
def dumps(self, obj):
- if isinstance(obj, int):
+ if isinstance(obj, int) and not isinstance(obj, bool):
return obj
return super().dumps(obj)
}}}
Would you like to prepare a patch?
> What was the rationale behind the `int` special-case? `django-redis` for
instance consistently sends all data through pickle.
We do this to have better atomicity of `incr()` and `decr()` operations
(see [https://github.com/django/django/pull/14437#issuecomment-915046037
discussion]).
--
Ticket URL: <https://code.djangoproject.com/ticket/33361#comment:1>
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