Error handler replies to errant command attempts

rocketbot.py

 Author: Ian Albert (@rocketsoup)
 Date: 2021-11-11
 """
+import traceback
 from discord import Intents
 from discord.ext import commands
 
 	def __init__(self, command_prefix, **kwargs):
 		super().__init__(command_prefix, **kwargs)
 
+	async def on_command_error(self, context: commands.Context, exception):
+		if context.guild is None or \
+				context.message.channel is None or \
+				context.message.author.bot:
+			return
+		if not context.message.author.permissions_in(context.message.channel).ban_members:
+			# Don't tell non-mods about errors
+			return
+		if isinstance(exception, (commands.errors.CommandError, )):
+			# Reply with the error message for ordinary command errors
+			await context.message.reply(
+				f'{CONFIG["failure_emoji"]} {exception}',
+				mention_author=False)
+			return
+		# Stack trace everything else
+		traceback.print_exception(type(exception), exception, exception.__traceback__)
+
 intents = Intents.default()
 intents.messages = True  # pylint: disable=assigning-non-slot
 intents.members = True  # pylint: disable=assigning-non-slot