From fc5fc08962651039305b93ef0731ba0672a9203e Mon Sep 17 00:00:00 2001
From: jack1142 <6032823+jack1142@users.noreply.github.com>
Date: Sun, 26 Jan 2020 18:16:13 +0100
Subject: [PATCH] [Downloader] Log errors from initialization task (#3444)

* Update downloader.py

* Create 3444.misc.rst

* enhance(downloader): don't type infinitely on init error

* fix(downloader): unindent `_ready_raised` check

* Update downloader.py
---
 changelog.d/downloader/3444.misc.rst |  1 +
 redbot/cogs/downloader/downloader.py | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 changelog.d/downloader/3444.misc.rst

diff --git a/changelog.d/downloader/3444.misc.rst b/changelog.d/downloader/3444.misc.rst
new file mode 100644
index 000000000..9a3798bfb
--- /dev/null
+++ b/changelog.d/downloader/3444.misc.rst
@@ -0,0 +1 @@
+ Log errors that may happen in initialization task.
diff --git a/redbot/cogs/downloader/downloader.py b/redbot/cogs/downloader/downloader.py
index c0099bf14..52dc73a1d 100644
--- a/redbot/cogs/downloader/downloader.py
+++ b/redbot/cogs/downloader/downloader.py
@@ -55,6 +55,7 @@ class Downloader(commands.Cog):
         self._repo_manager = RepoManager()
         self._ready = asyncio.Event()
         self._init_task = None
+        self._ready_raised = False
 
     def _create_lib_folder(self, *, remove_first: bool = False) -> None:
         if remove_first:
@@ -67,13 +68,30 @@ class Downloader(commands.Cog):
     async def cog_before_invoke(self, ctx: commands.Context) -> None:
         async with ctx.typing():
             await self._ready.wait()
+        if self._ready_raised:
+            await ctx.send(
+                "There was an error during Downloader's initialization."
+                " Check logs for more information."
+            )
+            raise commands.CheckFailure()
 
     def cog_unload(self):
         if self._init_task is not None:
             self._init_task.cancel()
 
     def create_init_task(self):
+        def _done_callback(task: asyncio.Task) -> None:
+            exc = task.exception()
+            if exc is not None:
+                log.error(
+                    "An unexpected error occurred during Downloader's initialization.",
+                    exc_info=exc,
+                )
+                self._ready_raised = True
+                self._ready.set()
+
         self._init_task = asyncio.create_task(self.initialize())
+        self._init_task.add_done_callback(_done_callback)
 
     async def initialize(self) -> None:
         await self._repo_manager.initialize()