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Redis model does not implement hash.

See original GitHub issue

Version: 3.4.0

Platform: Python 3.7

Description: in the new version Redis model has __eq__ implemented but not __hash__. Python docs(https://docs.python.org/3/reference/datamodel.html#object.__hash):

if it defines eq() but not hash(), its instances will not be usable as items in hashable collections.

A class that overrides eq() and does not define hash() will have its hash() implicitly set to None. When the hash() method of a class is None, instances of the class will raise an appropriate TypeError when a program attempts to retrieve their hash value, and will also be correctly identified as unhashable when checking isinstance(obj, collections.abc.Hashable).

If a class that overrides eq() needs to retain the implementation of hash() from a parent class, the interpreter must be told this explicitly by setting hash = <ParentClass>.hash.

Shouldn’t Redis implement __hash__ then?

There is an issue with kombu related to it: https://github.com/celery/kombu/issues/1152

Issue Analytics

State:
Created 4 years ago
Reactions:16
Comments:5 (1 by maintainers)

Top GitHub Comments

13reactions

dominik-blncommented, Jan 31, 2020

We are encountering the same problem when updating our Celery workers from 3.3.11 to v3.4.0:

[2020-01-31 12:22:49,722: CRITICAL/MainProcess] Unrecoverable error: TypeError("unhashable type: 'Redis'")
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/celery/worker/worker.py", line 205, in start
    self.blueprint.start(self)
  File "/usr/local/lib/python3.7/site-packages/celery/bootsteps.py", line 119, in start
    step.start(parent)
  File "/usr/local/lib/python3.7/site-packages/celery/bootsteps.py", line 369, in start
    return self.obj.start()
  File "/usr/local/lib/python3.7/site-packages/celery/worker/consumer/consumer.py", line 318, in start
    blueprint.start(self)
  File "/usr/local/lib/python3.7/site-packages/celery/bootsteps.py", line 119, in start
    step.start(parent)
  File "/usr/local/lib/python3.7/site-packages/celery/worker/consumer/mingle.py", line 40, in start
    self.sync(c)
  File "/usr/local/lib/python3.7/site-packages/celery/worker/consumer/mingle.py", line 44, in sync
    replies = self.send_hello(c)
  File "/usr/local/lib/python3.7/site-packages/celery/worker/consumer/mingle.py", line 57, in send_hello
    replies = inspect.hello(c.hostname, our_revoked._data) or {}
  File "/usr/local/lib/python3.7/site-packages/celery/app/control.py", line 154, in hello
    return self._request('hello', from_node=from_node, revoked=revoked)
  File "/usr/local/lib/python3.7/site-packages/celery/app/control.py", line 106, in _request
    pattern=self.pattern, matcher=self.matcher,
  File "/usr/local/lib/python3.7/site-packages/celery/app/control.py", line 477, in broadcast
    limit, callback, channel=channel,
  File "/usr/local/lib/python3.7/site-packages/kombu/pidbox.py", line 352, in _broadcast
    channel=chan)
  File "/usr/local/lib/python3.7/site-packages/kombu/pidbox.py", line 391, in _collect
    self.connection.drain_events(timeout=timeout)
  File "/usr/local/lib/python3.7/site-packages/kombu/connection.py", line 323, in drain_events
    return self.transport.drain_events(self.connection, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/kombu/transport/virtual/base.py", line 963, in drain_events
    get(self._deliver, timeout=timeout)
  File "/usr/local/lib/python3.7/site-packages/kombu/transport/redis.py", line 374, in get
    self._register_BRPOP(channel)
  File "/usr/local/lib/python3.7/site-packages/kombu/transport/redis.py", line 311, in _register_BRPOP
    if not self._client_registered(channel, channel.client, 'BRPOP'):
  File "/usr/local/lib/python3.7/site-packages/kombu/transport/redis.py", line 306, in _client_registered
    (channel, client, cmd) in self._chan_to_sock)
TypeError: unhashable type: 'Redis'

10reactions

andymccurdycommented, Jan 31, 2020

I’ll have this fixed later today including a 3.4.1 release.