Unexpected RealtimeSubscribeStates.TIMED_OUT 10 seconds after subscribe()

[SmaugPool]

Describe the bug

A subscription status RealtimeSubscribeStates.TIMED_OUT is received 10 seconds after subscribe() call, despite the subscription being still active.

2025-11-04 10:26:16,219 - INFO - Attempting to connect to WebSocket at wss://xxx.supabase.co/realtime/v1/websocket?apikey=sb_secret_xxx
2025-11-04 10:26:16,393 - INFO - WebSocket connection established successfully
2025-11-04 10:26:16,394 - INFO - send: {"event":"phx_join","payload":{"config":{"broadcast":null,"presence":{"key":"","enabled":false},"private":true,"postgres_changes":[]},"access_token":"sb_secret_xxx"},"topic":"realtime:test","ref":"1","join_ref":null}
2025-11-04 10:26:16,394 - INFO - send: {"event":"heartbeat","payload":{},"topic":"phoenix","ref":null,"join_ref":null}
2025-11-04 10:26:16,485 - INFO - receive: '{"ref":"1","event":"phx_reply","payload":{"status":"ok","response":{"postgres_changes":[]}},"topic":"realtime:test"}'
2025-11-04 10:26:16,486 - INFO - parsed message as event=<ChannelEvents.reply: 'phx_reply'> topic='realtime:test' payload=SuccessReplyMessage(status='ok', response=ReplyPostgresChanges(postgres_changes=[])) ref='1'
2025-11-04 10:26:16,486 - INFO - realtime:test : event=<ChannelEvents.reply: 'phx_reply'> topic='realtime:test' payload=SuccessReplyMessage(status='ok', response=ReplyPostgresChanges(postgres_changes=[])) ref='1'

2025-11-04 10:26:16,486 - WARNING - subscription status=RealtimeSubscribeStates.SUBSCRIBED err=None

2025-11-04 10:26:16,486 - INFO - receive: '{"ref":null,"event":"phx_reply","payload":{"status":"ok","response":{}},"topic":"phoenix"}'
2025-11-04 10:26:16,486 - INFO - parsed message as event=<ChannelEvents.reply: 'phx_reply'> topic='phoenix' payload=SuccessReplyMessage(status='ok', response=ReplyPostgresChanges(postgres_changes=None)) ref=None

2025-11-04 10:26:26,396 - WARNING - subscription status=RealtimeSubscribeStates.TIMED_OUT err=None

2025-11-04 10:26:41,396 - INFO - send: {"event":"heartbeat","payload":{},"topic":"phoenix","ref":null,"join_ref":null}
2025-11-04 10:26:41,425 - INFO - receive: '{"ref":null,"event":"phx_reply","payload":{"status":"ok","response":{}},"topic":"phoenix"}'
2025-11-04 10:26:41,425 - INFO - parsed message as event=<ChannelEvents.reply: 'phx_reply'> topic='phoenix' payload=SuccessReplyMessage(status='ok', response=ReplyPostgresChanges(postgres_changes=None)) ref=None

Reproduction

#!/usr/bin/env python3

import os, asyncio, logging
from supabase.client import AsyncClient

logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")

async def main():
    def on_subscribe(status, err):
        logging.warning(f"subscription status={status} err={err}")

    client = AsyncClient(os.environ.get("SUPABASE_URL"), os.environ.get("SUPABASE_KEY"))
    channel = client.channel("test", {"config": {"private": True}})
    await channel.subscribe(on_subscribe)
    while True:
        await asyncio.sleep(1)

asyncio.run(main())

Steps to reproduce

Run the reproduction snippet above.

Library affected

realtime

Library version

supabase 2.22.4

Python version

3.12.3

[grdsdev]

Hey @SmaugPool I'll try to reproduce this issue, but first, you leaked your secret key in the logs, if that is from a valid project, please rotate your key ASAP, you can check the docs on how to do it.

[SmaugPool]

Hey @SmaugPool I'll try to reproduce this issue, but first, you leaked your secret key in the logs, if that is from a valid project, please rotate your key ASAP, you can check the docs on how to do it.

Thank you. It's a test database and this key has been deleted.

[o-santi]

I think I've figured out the reason for this. I'll open a PR explaining it there.

[SmaugPool]

Thank you. As an aside, note that the issue was reported a few months ago on discord here:

https://discord.com/channels/839993398554656828/1404905876787040256/1404905876787040256

[o-santi]

Thank you for linking it, I have been outside of the discord up until now, I'll try going around it and see if I find any other issues I can be of any help.