Merge pull request python-discord#824 from python-discord/antimalware…

…-fix

Fix filtered extension string out of scope for antismalware log message

bot/cogs/antimalware.py

@@ -29,16 +29,16 @@ async def on_message(self, message: Message) -> None:
             return
 
         embed = Embed()
-        file_extensions = {splitext(message.filename.lower())[1] for message in message.attachments}
+        file_extensions = {splitext(attachment.filename.lower())[1] for attachment in message.attachments}
         extensions_blocked = file_extensions - set(AntiMalwareConfig.whitelist)
+        blocked_extensions_str = ', '.join(extensions_blocked)
         if ".py" in extensions_blocked:
             # Short-circuit on *.py files to provide a pastebin link
             embed.description = (
                 "It looks like you tried to attach a Python file - "
                 f"please use a code-pasting service such as {URLs.site_schema}{URLs.site_paste}"
             )
         elif extensions_blocked:
-            blocked_extensions_str = ', '.join(extensions_blocked)
             whitelisted_types = ', '.join(AntiMalwareConfig.whitelist)
             meta_channel = self.bot.get_channel(Channels.meta)
             embed.description = (