commands.FlagConverter 'MissingField' bug

[Nzii3]

Summary

Found a bug with commands.FlagConverter having weird behavior when subclass FlagConverter

Reproduction Steps

Subclass commands.FlagConverter, add a flag with commands.flag().

Minimal Reproducible Code

class Flags(commands.FlagConverter, prefix="?", delimiter=" "):
  reason: commands.flag(aliases=['r'])

Expected Results

The expected and ideal situation is for the code to not raise errors

Actual Results

Errors were raised, such as unexpected arguments (such as the aliases, required or name arguments) and arguments being passed as were classed when were passed as strings or lists.

Intents

all

System Information

Library version: latest (2.3.0)

Checklist

• I have searched the open issues for duplicates.
• I have shown the entire traceback, if possible.
• I have removed my token from display, if visible.

Additional Context

Discussed in the library discussion channel multiple times: https://discord.com/channels/881207955029110855/881735314987708456/1038933096013238302

[Nzii3]

Pull request created with fix: #1806