fix(redis): unwrap decorated __init__s when deriving the from_url kwargs allowlist

[anmolg1997]

The regression

redis-py >= 7.4 decorates AbstractConnection.__init__ with @deprecated_args (redis/utils.py), whose wrapper is declared (self, *args, **kwargs). _init_arg_names introspects the wrapper directly, so from redis-py 7.4 the MRO walk loses every real connection parameter and the from_url allowlist silently drops socket_timeout/socket_connect_timeout again — the exact regression the allowlist rework (#35273) fixed, reintroduced one dependency version later from the other side. A url-configured Redis that blackholes packets (NetworkPolicy misconfig) then blocks callers indefinitely instead of timing out.

The fix

Follow the __wrapped__ chain with inspect.unwrap before introspecting each __init__. @deprecated_args uses functools.wraps, so the chain leads to the true signature; unwrap is a no-op for undecorated __init__s.

Measured (socket_timeout present in the derived allowlist, before -> after)

redis-py	before	after
6.4.0	yes	yes
7.1.0	yes	yes
7.4.1	no	yes
8.1.0	no	yes

tests/test_litellm/test_redis.py at redis-py 8.1.0: 10 failures before, 3 after — the residual trio (sentinel/cluster password handling) fails identically without this change and at 6.4.0, so it is unrelated. At 6.4.0 the module result is unchanged by this PR.

Tests added

• test_init_arg_names_sees_through_decorated_inits — decorated-fake class proving the unwrap mechanism without depending on the installed redis-py.
• test_url_allowlist_always_carries_socket_timeouts — live invariant against the installed redis-py; the first assertion to go red if a future release changes signature declaration again.

Found while pinning a downstream consumer's redis version: we bisected the allowlist across 6.4/7.1/7.4.1/8.1.0 and traced the loss to the decorator's signature shadowing.

[greptile-apps]

Greptile Summary

This PR unwraps decorated Redis connection initializers before deriving URL-compatible keyword arguments, restoring socket timeout forwarding with newer redis-py releases

• Uses inspect.unwrap during MRO signature introspection
• Adds synthetic decorator coverage and an installed-version timeout allowlist invariant

Confidence Score: 5/5

The PR appears safe to merge, with no concrete changed-code failure identified

The unwrap operation preserves undecorated behavior while recovering wrapped initializer signatures, and the new tests cover both the mechanism and resulting timeout allowlist

Important Files Changed

Filename	Overview
litellm/_redis.py	Correctly unwraps decorated Redis initializer functions before collecting accepted positional and keyword-only parameters
tests/test_litellm/test_redis.py	Adds focused regression coverage without initiating Redis network traffic

_{Reviews (1): Last reviewed commit: "fix(redis): unwrap decorated __init__s w..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will not alter performance

✅ 31 untouched benchmarks

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_{Comparing anmolg1997:fix/redis-url-kwargs-unwrap-deprecated-args (99716c5) with litellm_internal_staging (f64479e)}