Errbot version 6.0.0+ fails to start because "Found more that one plugin for <class 'errbot.core.ErrBot'>"

[tmcevoy14]

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I am...

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• Requesting help with running my bot
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• Here about something else

I am running...

• Errbot version: 6.1.6
• OS version: CentOS 7.8.2003
• Python version: 3.6.8
• Using a virtual environment: yes

Issue description

I'm trying to upgrade our errbot version from 5.2.0 to 6.1.6 and after upgrading to version 6.1.6 errbot fails to start because of this error:
Found more that one plugin for <class 'errbot.core.ErrBot'>.

We are using errbot with the slack configuration and only have one backend defined. Any suggestions?

Our requirements.txt file looks like this:

pytz==2020.1           # (2020-04-20) - latest version
datadog==0.19.0        # (2018-06-04)
pyOpenSSL==17.5.0      # (2017-11-30)
errbot[slack]==6.1.6   # (2020-11-16) - latest version
slackclient==1.0.6     # (2017-08-02)
Markdown==3.3.3        # (2020-10-25) - latest version
pytest==3.7.1          # (2018-08-02)
paramiko==2.7.1        # (2019-12-09) - latest version
GitPython==2.1.11      # (2018-07-11)
black==20.8b1

We are using a custom slack backend that updates a few things for our use case:
BACKEND = 'CustomSlack'
BOT_EXTRA_BACKEND_DIR = os.getenv('BACKENDS_PATH', '/srv/backends')

And then our Custom Slack backend looks something like this (which is copied into /srv/backends when we build the image):

from plugins.libs.common import ui_blocks
from errbot.backends.base import Message
from errbot.backends.slack import (
    SlackBackend,
    SlackPerson,
    SlackRoomOccupant,
    SlackBot,
    SlackRoomBot,
    SlackRoom,
    SlackAPIResponseError,
)

log = logging.getLogger(__name__)


class CustomSlack(SlackBackend):

[Core]
Name = CustomSlack
Module = udemy_slack

[Python]
Version = 2+

[Documentation]
Description = Test stuff

Steps to reproduce

Upgrade to 6.1.6 and run errbot

Upgrade to
6.1.6 or 6.0.0

Additional info

none

[tmcevoy14]

Hi @sijis, can I get some support on this issue? It's blocking us from upgrading to version 6 of errbot and also upgrading our slackclient.

[nzlosh]

What version of python are you using to run errbot 5.2.0?

[tmcevoy14]

We're using python 3.6.8 to run errbot 5.2.0, and for the upgrade to errbot v6.

[nzlosh]

I've encountered this error too. The error comes from the multiple inheritance:
CustomSlack > SlackBackend > Errbot

I workaround the issue by removing the multiple inheritance, but you in your case this won't be useful. My guess is this PR may have change the behaviour of the import, but it's speculation.

[tmcevoy14]

Looks like the cause of the issue - I wonder if it can be reverted or what the reasoning for it was?

[nzlosh]

It will need to be confirmed as being the cause of the issue. I'm not sure if it can be reverted now or a new patch will need to be devised.

[tmcevoy14]

@sijis @gbin @attakei any idea if this could be fixed? Or if there's a workaround?

[sijis]

@tmcevoy14 I haven't been able to look at this.hopefully it's something I can review in the next week.

Something that you can try is basically copying the slack backend into your custom one and try to remove a layer of inheritance. It's not perfect but it should allow you to validate other items to address in the migration.

[tmcevoy14]

Hey @sijis, any update on this?

[sijis]

Its possible you are hitting this bug #1505.

[tmcevoy14]

Thanks for the update @sijis, will that PR be merged soon?

[sijis]

PR merged. should be in master.