DeprecationWarning: Call to '__init__' function with deprecated usage of input argument/s 'retry_on_timeout'

[jakerobers]

Getting the following warning for version "fakeredis>=2.29.0",

.venv/lib/python3.13/site-packages/fakeredis/aioredis.py:256: DeprecationWarning: Call to '__init__' function with deprecated usage of input argument/s 'retry_on_timeout'. (TimeoutError is included by default.) -- Deprecated since version 6.0.0.
    super().__init__(**kwargs)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html

Deleting retry_on_timeout from the kwarg in fakeredis/aioredis.py fixes the error, however I'm not sure if applying this patch is considered a breaking change if we made that adjustment (i.e. folks depending on older redis versions might find some incompatibility).

Going to ignore this warning for now in my pytest.ini, but is probably a fix to consider in future releases of this library.

[lamby]

I'm actually still seeing this when running Hypothesis' testsuite, even after applying the patches from the linked PR:

============================= test session starts ==============================
platform linux -- Python 3.13.3, pytest-8.3.5, pluggy-1.5.0
rootdir: /<<PKGBUILDDIR>>
configfile: pytest.ini
plugins: hypothesis-6.130.5, flaky-3.8.1, typeguard-4.4.2
collected 7028 items / 1 error / 4903 deselected / 1 skipped / 2125 selected

==================================== ERRORS ====================================
_ ERROR collecting .pybuild/cpython3_3.13_hypothesis/build/tests/redis/test_redis_exampledatabase.py _
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 341, in from_call
    result: TResult | None = func()
                             ~~~~^^
  File "/usr/lib/python3/dist-packages/_pytest/runner.py", line 389, in collect
    return list(collector.collect())
                ~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 549, in collect
    self._register_setup_module_fixture()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 562, in _register_setup_module_fixture
    self.obj, ("setUpModule", "setup_module")
    ^^^^^^^^
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 284, in obj
    self._obj = obj = self._getobj()
                      ~~~~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 546, in _getobj
    return importtestmodule(self.path, self.config)
  File "/usr/lib/python3/dist-packages/_pytest/python.py", line 493, in importtestmodule
    mod = import_path(
        path,
    ...<2 lines>...
        consider_namespace_packages=config.getini("consider_namespace_packages"),
    )
  File "/usr/lib/python3/dist-packages/_pytest/pathlib.py", line 587, in import_path
    importlib.import_module(module_name)
    ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/usr/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/usr/lib/python3/dist-packages/_pytest/assertion/rewrite.py", line 185, in exec_module
    exec(co, module.__dict__)
    ~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/<<PKGBUILDDIR>>/.pybuild/cpython3_3.13_hypothesis/build/tests/redis/test_redis_exampledatabase.py", line 29, in <module>
    {"redis": FakeRedis(), "expire_after": 10},  # not a timedelta
              ~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/fakeredis/_connection.py", line 179, in __init__
    super().__init__(**kwds)
    ~~~~~~~~~~~~~~~~^^^^^^^^
  File "/usr/lib/python3/dist-packages/redis/utils.py", line 184, in wrapper
    warn_deprecated_arg_usage(
    ~~~~~~~~~~~~~~~~~~~~~~~~~^
        arg, func.__name__, reason, version, stacklevel=3
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3/dist-packages/redis/utils.py", line 147, in warn_deprecated_arg_usage
    warnings.warn(msg, category=DeprecationWarning, stacklevel=stacklevel)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
DeprecationWarning: Call to '__init__' function with deprecated usage of input argument/s 'retry_on_timeout'. (TimeoutError is included by default.) -- Deprecated since version 6.0.0.

Originally filed as https://bugs.debian.org/1106650

[cunla]

The way that it works now is it takes the arguments from redis.Redis - so if you use a redis-py version that has the argument with a deprecation warning, it will have it.

If you upgrade redis-py to a version where the argument is removed - you won't have the warning.

[lamby]

If you upgrade redis-py to a version where the argument is removed - you won't have the warning.

Getcha, although that's a little misleading as redis-py, even in Git, still has this argument. So it is only when folks upgrade to future versions of redis-py that have (finally) removed this argument, then there will be no warning. (Right?)

I can silence the warning within the Hypothesis testsuite - as I understand it, this is only kinda an issue because of the way pytest is treating warnings as errors.

[cunla]

what version of redis-py are you using? I assume 6+ since this is when it became deprecated.

You can see in the code FakeRedis takes the arguments as they are defined in redis-py

[lamby]

what version of redis-py are you using? I assume 6+ since this is when it became deprecated.

Well, here's the line in the latest Git HEAD of redis-py that still lists retry_on_timeout, which your code will pick up via inspect.signature.

[chris-fj]

Hey, guys. I'm using redis==6.2.0 and fakeredis==2.29.0 and I'm seeing this warning. I'm a bit slow today but I see this issue closed and I'm still receiving this warning. Shouldn't this be reopened? As upstream redis-py is still using this parameter, is it expected behavior that we receive this warning?

[cunla]

yes. fakeredis is taking the parameters from redis-py definition. So if your redis-py version gives a warning, fakeredis gives a warning.

[chris-fj]

So what I gather is, redis-py defines the retry_on_timeout argument on the __init__ (L232) and then it's picked in fakeredis via inspect.signature. However, it's marked as deprecated on L216 and therefore, every time we use redis-py we will have the warning until they either decide to remove the parameter or the deprecation notice.

@cunla as a suggestion for the future, it would be great to pick those parameters by default using inspect.signature but allowing manual override to prevent this kind of issue. Thanks for the clarification in any case.

[cunla]

So what I gather is, redis-py defines the retry_on_timeout argument on the __init__ (L232) and then it's picked in fakeredis via inspect.signature. However, it's marked as deprecated on L216 and therefore, every time we use redis-py we will have the warning until they either decide to remove the parameter or the deprecation notice.

@cunla as a suggestion for the future, it would be great to pick those parameters by default using inspect.signature but allowing manual override to prevent this kind of issue. Thanks for the clarification in any case.

I see your point, if the parameter is deprecated, don't pass it by default, so the warning won't appear... I wonder now how I can pick up list of deprecated parameters :)

[chris-fj]

I managed to get this:

>>> import redis
>>>
>>> closure = redis.Redis.__init__.__closure__
>>> param_name = "args_to_warn"
>>> if closure:
...     for cell in closure:
...         value = cell.cell_contents
...         if isinstance(value, list) and param_name == "args_to_warn":
...             dd = value
...         elif isinstance(value, dict) and param_name in value:
...             dd = value[param_name]
...
>>> dd
['retry_on_timeout']

However, to my taste, this seems too dependent on the implementation of redis-py for deprecation notices and can break your code if they ever decide to change it. I was thinking on two options:

• the first one would be that a parameters parameter be added to the __init__ method of FakeRedisMixin, this parameter would default to None (so it doesn't break with existing implementations). Then, the logic of __init__ would populate it with the parameters from inspect.signature(redis.Redis.__init__) if you didn't pass anything (i.e. parameters=None). If you pass a list of parameters, then that list would be used instead
• the second one would be to implement a blacklist of parameters (None by default). If you specify it (i.e. not None), it would use those parameters in inspect.signature(redis.Redis.__init__) not in blacklist.