AttributeError when using Unix sockets with OTel metrics (v7.2.0)

[Bojun-Feng]

After upgrading to redis-py 7.2.0 (released Feb 16, 2026), any Redis operations using Unix domain socket connections crash with:

AttributeError: 'UnixDomainSocketConnection' object has no attribute 'port'

Seems like a regression introduced by the new OpenTelemetry native metrics support added in #3954. The OTel instrumentation added accesses conn.host and conn.port unconditionally when recording metrics:

# redis/client.py - multiple locations
record_operation_duration(
    command_name=command_name,
    duration_seconds=time.monotonic() - start_time,
    server_address=conn.host,
    server_port=conn.port,  # <-- AttributeError for UnixDomainSocketConnection - no port attribute
    db_namespace=str(conn.db),
)

Environment

1. Redis server listening on a Unix socket (not TCP)
2. redis-py 7.2.0
3. Execute any Redis command (e.g., PING)

Reproduction Script

Here's the Python script to reproduce the issue:

"""
Requirements:
- Redis server running with: redis-server --unixsocket /tmp/redis-test.sock --unixsocketperm 777 --port 0 --daemonize yes
- redis-py 7.2.0: pip install redis==7.2.0
"""
import redis
def main():
    r = redis.Redis(
        unix_socket_path='/tmp/redis-test.sock',
        encoding='utf-8',
        decode_responses=True
    )
    
    print(f'redis-py version: {redis.__version__}')
    print(f'Connection class: {r.connection_pool.connection_class.__name__}')
    print()
    print('Executing PING command...')
    
    # This triggers _execute_command() which crashes at line 748:
    #   server_port=conn.port,  # AttributeError!
    result = r.ping()
    print(f'Result: {result}')
if __name__ == '__main__':
    main()

[Bojun-Feng]

Seems like the easiest fix would be to add a dummy port feature for the Unix sockets