Can't create alert posting to slack channel

[sintell]

Important Details

How are you running Sentry?
On-Premise w/ Docker, version x9.1.2

Description

[What happened]
Can't send alerts that'll post messages to slack. Link substitution isn't working. Tested this with both public and private channels.

Steps to Reproduce

1. Add slack integration from settings page following https://docs.sentry.io/product/integrations/slack/
2. Proceed to "New alert" for any project
3. Attempt to create new alert that will post to slack channel
4. Get an error saying The slack resource "my-public-or-private-channel" does not exist or has not been granted access in the MyCompany Slack workspace.
   Also in logs for sentry-web I can see the following record:
   10:43:30 [INFO] sentry.rules: rule.slack.channel_list_failed (error=u'method_deprecated')

What you expected to happen

I should be able to create alerts that will post to slack using new global slack integration

What to do

I saw a bunch of different issues related to this problem, and as I saw here #19446 it was fixed for v10, but as far as I can see the fix was never backported for 9.1.x branch. Is it possible to backport it somehow, or is there any protocols to help me to contribute on that matter.

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Accepted, I will leave it alone ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀

[manuzope]

Looks like someone was able to figure out a backport for 9.1.x: #19446 (comment). Maybe try applying that patch to a forked version of your Sentry?

But there is no official backporting process.