Add generics to Interaction params

[diceroll123]

Summary

ty gives this,

Allows interaction.client to narrow to the bot class instead of the basic discord.Client.

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• 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, ...)

[The-Red-Dragons]

👍 Great fix! This addresses a common pain point for type-safe Discord bot development.

We maintain a large production Discord bot and frequently encounter this issue when subclassing callbacks. Currently, we have to use type ignores or casts in views, modals, and error handlers:

class MyView(discord.ui.View):
    async def on_error(self, interaction: discord.Interaction, error: Exception, item):
        # Currently required workaround:
        bot: MyBot = interaction.client  # type: ignore[assignment]
        await bot.error_manager.handle(interaction, error)

With this PR, the generic parameter will properly narrow interaction.client to our custom bot class, eliminating the need for type ignores.

One minor suggestion: Is Modal.on_error() also affected by this issue? I noticed it's not included in the current changeset - might be worth checking if it needs the same treatment.

Thanks for the fix! 🎉

[diceroll123]

Modal.on_error seems fine,

discord.py/discord/ui/modal.py

Line 159 in 0052878

async def on_error(self, interaction: Interaction[ClientT], error: Exception, /) -> None:

[TheServerit]

Though Pyright on Strict mode complains even in places where the base function already does implement interaction: Interaction[ClientT]:

"Interaction[ClientT@callback]" is not assignable to "Interaction[Bot]"
  Type parameter "ClientT@Interaction" is covariant, but "ClientT@callback" is not a subtype of "Bot"
    "Client*" is not assignable to "Bot"

(Bot is my subclass of AutoShardedBot which subclasses Client)
So unless I misunderstand something, I assume this PR will not fix this issue in particular?