Adding on_check_failure to View class

[Kile]

Summary

I have submitted this pull request before but Danny ended up denying it. I still find this relevant and useful so I am submitting it here again.

This pull request adds the Coro on_check_failure to the View class which is called when interaction_check returns False and defers the interaction, if not previously responded to, per default (EDIT: it now does not defer the interaction per default anymore).

Why this is needed:
interaction_check's purpose is to check if the interaction should go through, not really to handle the case of it not going through. A separate method handling what to do when the check fails seems more clean and useful to deal with that.
So thing code which would previously look like

async def interaction_check(self, interaction: discord.Interaction) -> bool:
    if not some_check():
        await interaction.response.defer()
        return False
    return True

looks now like

async def on_check_failure(self, interaction: discord.Interaction) -> None:
    await interaction.response.defer()

async def interaction_check(self, interaction: discord.Interaction) -> bool:
    return some_check():

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, typehinting, examples, ...)

[plun1331]

I feel like doing this in interaction_check is easier, mostly because you would know what condition failed.

The feature could have it's uses though.

[krittick]

I think it would be best to just add the method itself (to allow subclassing and better code organization) but not provide a default behavior (i.e. don't auto-defer on failure).

[Kile]

I don't mind changing it to that if you'd like me to

[plun1331]

Is anything going to happen with this for 2.0?

[krittick]

Is anything going to happen with this for 2.0?

It's marked as a 2.1 feature and still in draft.

[baronkobama]

The code looks good to me. 👍