fix: TypeError when using Literal type hint with option decorator

[FrederickStempfle]

Summary

Fixes #3091

When a slash command option is typed as Literal["jpeg", "png", ...] without explicitly passing input_type, the Option init passes the Literal directly to SlashCommandOptionType.from_datatype, which calls issubclass() on it and crashes since Literal isn't a class.

The fix resolves Literal types to their base type (e.g. Literal["a", "b"] → str) early in Option.__init__, before it reaches from_datatype.

Information

• 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, ...).

Checklist

• I have searched the open pull requests for duplicates.
• 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.
• I have updated the changelog to include these changes.

[pycord-app]

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[plun1331]

Use the pull request template please: https://github.com/Pycord-Development/.github/blob/main/PULL_REQUEST_TEMPLATE.md

[plun1331]

• Your checks are failing
• A changelog is needed
• Please test the fix and provide test code

[FrederickStempfle]

Hey, thanks for the review.

Checks: Those CI failures are infrastructure-related, not from this PR. They're failing the same way on master and every other open PR right now (jobs finishing in 3-4s with empty step logs). The Semantic Title one is on me though, I'll update the title to fix: format.

Changelog: My bad, will add it.

Test code: Here's what I tested with (same pattern as the existing test_typing_annotated.py tests):

from typing import Literal
from discord.commands.core import SlashCommand
from discord import Bot, SlashCommandOptionType
from discord.commands import option

@option("fmt", choices=["jpeg", "png", "gif", "webp", "tiff", "bmp"])
async def convert(ctx, fmt: Literal["jpeg", "png", "gif", "webp", "tiff", "bmp"]):
    await ctx.respond(fmt)

cmd = SlashCommand(convert)
bot = Bot()
bot.add_application_command(cmd)

opt = cmd.to_dict()["options"][0]
assert opt["type"] == SlashCommandOptionType.string.value

Without the fix this throws TypeError: issubclass() arg 1 must be a class in from_datatype, with the fix it resolves the Literal to str and passes.

Will push the title fix + changelog shortly.

[plun1331]

After some internal discussion, we're closing this as it appears it was made using AI. If we're wrong, feel free to let us know in our Discord: https://discord.gg/pycord