From fce2ef553474007dc413fd599454274fce7f6416 Mon Sep 17 00:00:00 2001
From: Rapptz <rapptz@gmail.com>
Date: Sun, 13 Aug 2017 20:52:12 -0400
Subject: [PATCH] [commands] Raise when an invalid prefix is given.
Fixes #712
---
discord/ext/commands/bot.py | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/discord/ext/commands/bot.py b/discord/ext/commands/bot.py
index 55c97301..5b872f88 100644
--- a/discord/ext/commands/bot.py
+++ b/discord/ext/commands/bot.py
@@ -785,20 +785,33 @@ class BotBase(GroupMixin):
message: :class:`discord.Message`
The message context to get the prefix of.
+ Raises
+ --------
+ :exc:`.ClientException`
+ The prefix was invalid. This could be if the prefix
+ function returned None, the prefix list returned no
+ elements that aren't None, or the prefix string is
+ empty.
+
Returns
--------
Union[List[str], str]
A list of prefixes or a single prefix that the bot is
listening for.
"""
- prefix = self.command_prefix
+ prefix = ret = self.command_prefix
if callable(prefix):
ret = prefix(self, message)
if asyncio.iscoroutine(ret):
ret = yield from ret
- return ret
- else:
- return prefix
+
+ if isinstance(ret, (list, tuple)):
+ ret = [p for p in ret if p]
+
+ if not ret:
+ raise ClientException('invalid prefix (could be an empty string, empty list, or None)')
+
+ return ret
@asyncio.coroutine
def get_context(self, message, *, cls=Context):
@@ -840,7 +853,7 @@ class BotBase(GroupMixin):
prefix = yield from self.get_prefix(message)
invoked_prefix = prefix
- if not isinstance(prefix, (tuple, list)):
+ if isinstance(prefix, str):
if not view.skip_string(prefix):
return ctx
else: