Bug in PubSub client health check handling

[ManelCoutinhoSensei]

Hi, I think there might be an inconsistency (or bug) in the PubSub client related to how health check responses are handled.

In my application, I encountered the following error:

File "/usr/local/lib/python3.12/dist-packages/redis/client.py", line 1016, in punsubscribe
    return self.execute_command("PUNSUBSCRIBE", *args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/dist-packages/redis/client.py", line 874, in execute_command
    self.clean_health_check_responses()
  File "/usr/local/lib/python3.12/dist-packages/redis/client.py", line 890, in clean_health_check_responses
    raise PubSubError(
redis.exceptions.PubSubError: A non health check response was cleaned by execute_command: redis-py-health-check

After reading through the code, I noticed that while is_health_check_response allows for receiving either a list of ["pong", "redis-py-health-check"] or only "redis-py-health-check", this behavior seems inconsistent between the decode_responses=True and decode_responses=False cases:

redis-py/redis/client.py

Lines 826 to 830 in 028245c

	self.health_check_response_b = self.encoder.encode(self.HEALTH_CHECK_MESSAGE)
	if self.encoder.decode_responses:
	self.health_check_response = ["pong", self.HEALTH_CHECK_MESSAGE]
	else:
	self.health_check_response = [b"pong", self.health_check_response_b]

This inconsistency means that the check here:

redis-py/redis/client.py

Lines 1004 to 1007 in 028245c

	return response in [
	self.health_check_response, # If there was a subscription
	self.health_check_response_b, # If there wasn't
	]

Can yield:

• With decode_responses=False:

[[b"pong", b"redis-py-health-check"], b"redis-py-health-check"]

• With decode_responses=True:

[["pong", "redis-py-health-check"], b"redis-py-health-check"]

Instead of the expected:

[["pong", "redis-py-health-check"], "redis-py-health-check"]

I might be mistaken, and the issue could originate elsewhere, but this seems like a possible source of the inconsistency.

Environment:

• redis-py version: 6.4.0
• Python version: 3.12

[petyaslavova]

Hi @ManelCoutinhoSensei, thank you for reporting this! We will have a look at it.