Removing the threading.Lock locks and replacing them with RLock objects to avoid deadlocks.

[petyaslavova]

Pull Request check-list

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Description of change

Usage of threading.Lock has introduced deadlocks in the client.
With this change, I'm removing all places that can cause such issues.
The change is breaking, because it changes the interfaces of several objects and cannot be released before the next major release, which will be 7.0.0

[Copilot]

Pull Request Overview

This PR replaces all usages of threading.Lock with threading.RLock to prevent deadlocks, updating both tests and core locking interfaces. It’s a breaking change that adjusts constructor signatures and type hints to expect reentrant locks.

• Swapped Lock for RLock in multiple test files to align with new behavior.
• Updated constructor parameters and type annotations in redis/event.py, redis/connection.py, and redis/client.py to use RLock.
• Removed legacy non-reentrant lock branches and related TODOs in redis/connection.py.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/test_credentials.py	Changed mock pools’ _lock initialization from Lock to RLock.
tests/test_connection.py	Updated CacheProxyConnection instantiation to pass an RLock.
tests/test_cluster_transaction.py	Replaced mock_pool._lock = Lock() with RLock().
redis/event.py	Refactored connection_lock parameter/type to RLock.
redis/connection.py	Adjusted pool_lock type to RLock; removed non-reentrant fallback code.
redis/client.py	Swapped client locks to RLock and removed outdated TODOs.

Comments suppressed due to low confidence (3)

tests/test_credentials.py:326

• [nitpick] Add a unit test that acquires the same RLock twice in a row to verify reentrant behavior and ensure no deadlock occurs under nested acquisitions.

mock_pool._lock = threading.RLock()

redis/connection.py:813

• Update the constructor docstring for this class to document the change from Lock to RLock in the pool_lock parameter, since this is now part of the public API and a breaking change.

pool_lock: threading.RLock,

tests/test_connection.py:496

• [nitpick] Consider extracting the repeated instantiation of CacheProxyConnection with an RLock into a pytest fixture to reduce duplication and improve clarity across tests.

proxy_connection = CacheProxyConnection(mock_connection, mock_cache, threading.RLock())