Handle deprecations in asyncio (#3509)

* passing loop to certain things was deprecated. additionally, `asyncio.get_event_loop()` is being deprecated

* awesome, checks are functioning as intended

* fun with fixtures

* we can just stop misuing that anyhow

* Update redbot/pytest/downloader.py

Co-Authored-By: jack1142 <6032823+jack1142@users.noreply.github.com>

Co-authored-by: jack1142 <6032823+jack1142@users.noreply.github.com>

redbot/core/utils/__init__.py

@@ -1,4 +1,5 @@
 import asyncio
+import warnings
 from asyncio import AbstractEventLoop, as_completed, Semaphore
 from asyncio.futures import isfuture
 from itertools import chain
@@ -177,14 +178,20 @@ def bounded_gather_iter(
     TypeError
         When invalid parameters are passed
     """
-    if loop is None:
-        loop = asyncio.get_event_loop()
+    if loop is not None:
+        warnings.warn(
+            "Explicitly passing the loop will not work in Red 3.4+ and is currently ignored."
+            "Call this from the related event loop.",
+            DeprecationWarning,
+        )
+
+    loop = asyncio.get_running_loop()
 
     if semaphore is None:
         if not isinstance(limit, int) or limit <= 0:
             raise TypeError("limit must be an int > 0")
 
-        semaphore = Semaphore(limit, loop=loop)
+        semaphore = Semaphore(limit)
 
     pending = []
 
@@ -195,7 +202,7 @@ def bounded_gather_iter(
         cof = _sem_wrapper(semaphore, cof)
         pending.append(cof)
 
-    return as_completed(pending, loop=loop)
+    return as_completed(pending)
 
 
 def bounded_gather(
@@ -228,15 +235,21 @@ def bounded_gather(
     TypeError
         When invalid parameters are passed
     """
-    if loop is None:
-        loop = asyncio.get_event_loop()
+    if loop is not None:
+        warnings.warn(
+            "Explicitly passing the loop will not work in Red 3.4+ and is currently ignored."
+            "Call this from the related event loop.",
+            DeprecationWarning,
+        )
+
+    loop = asyncio.get_running_loop()
 
     if semaphore is None:
         if not isinstance(limit, int) or limit <= 0:
             raise TypeError("limit must be an int > 0")
 
-        semaphore = Semaphore(limit, loop=loop)
+        semaphore = Semaphore(limit)
 
     tasks = (_sem_wrapper(semaphore, task) for task in coros_or_futures)
 
-    return asyncio.gather(*tasks, loop=loop, return_exceptions=return_exceptions)
+    return asyncio.gather(*tasks, return_exceptions=return_exceptions)

redbot/core/utils/menus.py

@@ -5,6 +5,7 @@
 import asyncio
 import contextlib
 import functools
+import warnings
 from typing import Union, Iterable, Optional
 import discord
 
@@ -200,7 +201,9 @@ def start_adding_reactions(
                 await message.add_reaction(emoji)
 
     if loop is None:
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
+    else:
+        warnings.warn("Explicitly passing the loop will not work in Red 3.4+", DeprecationWarning)
 
     return loop.create_task(task())