From fc22d288be30d8cfab7b03c2fdf23f3e03d3dffc Mon Sep 17 00:00:00 2001
From: khazhyk <khazhy@gmail.com>
Date: Tue, 4 Jul 2017 19:13:27 -0700
Subject: [PATCH] [commands] unload cog submodules

When unloading cogs, currently we do not remove submodules from
sys.modules, meaning they will not be reloaded. Removing here
makes new imports reload from file. Of course, any already imported
modules will still hold a reference to the old module, since they
will not re-import it, and will not be forcably unloaded.
---
 discord/ext/commands/bot.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/discord/ext/commands/bot.py b/discord/ext/commands/bot.py
index 85b8d1341..34ab30e2c 100644
--- a/discord/ext/commands/bot.py
+++ b/discord/ext/commands/bot.py
@@ -768,6 +768,9 @@ class BotBase(GroupMixin):
             del lib
             del self.extensions[name]
             del sys.modules[name]
+            for module in list(sys.modules.keys()):
+                if _is_submodule(lib_name, module):
+                    del sys.modules[module]
 
     # command processing