Error-handle a timeout error when loading plugins (#3330)

* Fix registry loading errors

* Fix black formatting

* Repo consistency

* Change code cleanness as requested by taku

---------

Co-authored-by: Taku <45324516+Taaku18@users.noreply.github.com>

cogs/plugins.py

@@ -6,22 +6,21 @@
 import sys
 import typing
 import zipfile
-from importlib import invalidate_caches
 from difflib import get_close_matches
+from importlib import invalidate_caches
 from pathlib import Path, PurePath
 from re import match
 from site import USER_SITE
 from subprocess import PIPE
 
 import discord
 from discord.ext import commands
-
 from packaging.version import Version
 
 from core import checks
 from core.models import PermissionLevel, getLogger
 from core.paginator import EmbedPaginatorSession
-from core.utils import truncate, trigger_typing
+from core.utils import trigger_typing, truncate
 
 logger = getLogger(__name__)
 
@@ -132,8 +131,11 @@ async def cog_load(self):
 
     async def populate_registry(self):
         url = "https://raw.githubusercontent.com/modmail-dev/modmail/master/plugins/registry.json"
-        async with self.bot.session.get(url) as resp:
-            self.registry = json.loads(await resp.text())
+        try:
+            async with self.bot.session.get(url) as resp:
+                self.registry = json.loads(await resp.text())
+        except asyncio.TimeoutError:
+            logger.warning("Failed to fetch registry. Loading with empty registry")
 
     async def initial_load_plugins(self):
         for plugin_name in list(self.bot.config["plugins"]):
@@ -638,6 +640,14 @@ async def plugins_registry(self, ctx, *, plugin_name: typing.Union[int, str] = N
 
         registry = sorted(self.registry.items(), key=lambda elem: elem[0])
 
+        if not registry:
+            embed = discord.Embed(
+                color=self.bot.error_color,
+                description="Registry is empty. This could be because it failed to load.",
+            )
+            await ctx.send(embed=embed)
+            return
+
         if isinstance(plugin_name, int):
             index = plugin_name - 1
             if index < 0: