[commands] Guarantee that local error handler is called before generic.

discord/ext/commands/bot.py

@@ -632,7 +632,7 @@ class BotBase(GroupMixin):
             try:
                 yield from ctx.command.invoke(ctx)
             except CommandError as e:
-                ctx.command.dispatch_error(e, ctx)
+                yield from ctx.command.dispatch_error(e, ctx)
             else:
                 self.dispatch('command_completion', ctx)
         elif ctx.invoked_with:

discord/ext/commands/core.py

@@ -145,18 +145,18 @@ class Command:
         self.parent = None
         self._buckets = CooldownMapping(kwargs.get('cooldown'))
 
+    @asyncio.coroutine
     def dispatch_error(self, error, ctx):
         try:
             coro = self.on_error
         except AttributeError:
             pass
         else:
-            loop = ctx.bot.loop
             injected = wrap_callback(coro)
             if self.instance is not None:
-                discord.compat.create_task(injected(self.instance, error, ctx), loop=loop)
+                yield from injected(self.instance, error, ctx)
             else:
-                discord.compat.create_task(injected(error, ctx), loop=loop)
+                yield from injected(error, ctx)
         finally:
             ctx.bot.dispatch('command_error', error, ctx)