Allow using Discord threads

[A5rocks]

Absolutely hacky support for Discord threads. There's a couple important details about Discord threads:

• they do not support topics
• (a bit less importantly, they can't be marked NSFW nor have overwrites)

The lack of topic support is troubling given that Modmail stuffs thread information into the channel topic. I updated some things to work based off the genesis message and -- since that does not contain the title -- disallowed setting titles for thread in Discord threads.

This can be used by setting main_category_id to a text channel, rather than a category channel. It worked in some basic tests I did locally, but I haven't checked in a more intensive environment.

[martinbndr]

This would be a nice idea, but this completely overwrites the whole system to threads which can be a problem. There are servers that would like to use the old/original behaiviour from the current modmail. So to have a chance for being considered it would be better to implement this as an optional feature with a configuration variable.

[lorenzo132]

This would be a nice idea, but this completely overwrites the whole system to threads which can be a problem. There are servers that would like to use the old/original behaiviour from the current modmail. So to have a chance for being considered it would be better to implement this as an optional feature with a configuration variable.

I agree with this. If it were to be made a configurable option and thoroughly tested in an intensive environment, I’d be 100% okay with merging this.

[A5rocks]

This still has the old behavior -- it only uses threads if main_category_id is a text channel. (At least it should work with a category; I only tested with None and with a text channel.)

[martinbndr]

Ah okay

[martinbndr]

I have not tested everything yet but a few things I have noticed:

• During the bot tries to create a modmail thread it´ll fails with this error:

await channel.edit(topic=f"User ID: {user_id}")
TypeError: Thread.edit() got an unexpected keyword argument 'topic'

• Bot logging shows:
  02/18/25 00:02:18 core.thread[1339] - WARNING: Found existing thread for 618805150756110336 but the channel is invalid.
  So there are these and may more parts that still does not fully recognize the main_category_d is a text channel

And may it would be better to let user configure it sth else. Because the variable name main_categpory_id would be a bit confusing for the users as they are thinking only categories are valid.

[A5rocks]

I'm unable to reproduce either of those -- do you have some steps I should follow? (I can see where in the code they happen and could blindly put guards up, but I want to know in what case they happen)

[martinbndr]

I just used the config set command and configured the main_category_id to a text channel.
and then dmed the bot to start a new thread.

[martinbndr]

Line 1305/1322 (including your changes) could be the issue. Also wondering why you didnt get this error. Have you tested it properly?

[A5rocks]

I've been testing repeating:

1. Set main category id to a category
2. Create a thread
3. Close it
4. Switch main category id to a text channel
5. Create a thread
6. Close it

Obviously with stuff like checking switching 3 and 4. Nothing gets logged or breaks.

I'll try looking at the code some more and see if I can see a way for maybe a .find call to race against sending a genesis message?

[A5rocks]

I took a wild guess -- let me know if that fixes it (I am still unable to repro...)

(for people skimming this PR: I changed modmail threads to cache only when completely initialized, including their first message)