discord.py-rewrite - Manipulating exceptions through cogs - discord

Question

So, on my main file bot.py, I have:
class Bot(commands.Bot):
# BOT ATTRIBUTES
class MyException(Exception):
def __init__(self, argument):
self.argument = argument
bot = Bot(...)
#bot.event
async def on_command_error(ctx, error):
if isistance(error, bot.MyException):
await ctx.send("{} went wrong!".format(error.argument))
else:
print(error)
Now I also have a cog file, where I sometimes want to throw the Bot().MyException exception:
class Cog(commands.Cog):
def __init__(self, bot):
self.bot = bot
#commands.command()
async def a_command(self, ctx):
if a_condition:
raise self.bot.MyException("arg")
When I run the code, if the a_condition has been validated, the program raises the MyException exception, but the BOT do not send the desired message in the on_command_error() function in bot.py. Instead, the exception gets printed in the console and I get this error message:
Command raised an exception: MyException: arg
Can anyone please tell me how to make the BOT say the desired message in on_command_error() in bot.py?

Answer 1

Commands will only raise exceptions derived from CommandError. When your command raises a non-CommandError exception, it will be wrapped in a CommandInvokeError:
#bot.event
async def on_command_error(ctx, error):
if isinstance(error, commands.CommandInvokeError):
if isinstance(error.original, bot.MyException):
await ctx.send("{} went wrong!".format(error.argument))
return
print(error)

Answer 2

#Patrick Haugh Thank you a lot for this info, I managed to solve this issue by inheriting MyException class from commands.CommandError instead of Exception.
Basically by writing :
class MyException(commands.CommandError):
def __init__(self, argument):
self.argument = argument
instead of:
class MyException(Exception):
def __init__(self, argument):
self.argument = argument
and then leaving:
#bot.event
async def on_command_error(ctx, error):
if isistance(error, bot.MyException):
await ctx.send("{} went wrong!".format(error.argument))
else:
print(error)