From 7689ac8c6a3ea7eb594d3637ece411753f085ab1 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Wed, 2 Sep 2020 21:54:46 -0700
Subject: [PATCH] bpo-41696: Fix handling of debug mode in asyncio.run
 (GH-22069)
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* bpo-41696: Fix handling of debug mode in asyncio.run

This allows PYTHONASYNCIODEBUG or -X dev to enable asyncio debug mode
when using asyncio.run

* 📜🤖 Added by blurb_it.

Co-authored-by: hauntsaninja <>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
(cherry picked from commit 0770ad948cb6d9f7f6c4002efd83e27c27069808)

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 Lib/asyncio/runners.py                                       | 5 +++--
 Lib/test/test_asyncio/test_runners.py                        | 3 +++
 .../next/Library/2020-09-03-01-35-32.bpo-41696.zkYGre.rst    | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2020-09-03-01-35-32.bpo-41696.zkYGre.rst

diff --git a/Lib/asyncio/runners.py b/Lib/asyncio/runners.py
index 2e37e18b45fc15..d2fa8b7f13861c 100644
--- a/Lib/asyncio/runners.py
+++ b/Lib/asyncio/runners.py
@@ -5,7 +5,7 @@
 from . import tasks
 
 
-def run(main, *, debug=False):
+def run(main, *, debug=None):
     """Execute the coroutine and return the result.
 
     This function runs the passed coroutine, taking care of
@@ -39,7 +39,8 @@ async def main():
     loop = events.new_event_loop()
     try:
         events.set_event_loop(loop)
-        loop.set_debug(debug)
+        if debug is not None:
+            loop.set_debug(debug)
         return loop.run_until_complete(main)
     finally:
         try:
diff --git a/Lib/test/test_asyncio/test_runners.py b/Lib/test/test_asyncio/test_runners.py
index 3b58ddee443adf..b9ae02dc3c04e0 100644
--- a/Lib/test/test_asyncio/test_runners.py
+++ b/Lib/test/test_asyncio/test_runners.py
@@ -87,6 +87,9 @@ async def main(expected):
 
         asyncio.run(main(False))
         asyncio.run(main(True), debug=True)
+        with mock.patch('asyncio.coroutines._is_debug_mode', lambda: True):
+            asyncio.run(main(True))
+            asyncio.run(main(False), debug=False)
 
     def test_asyncio_run_from_running_loop(self):
         async def main():
diff --git a/Misc/NEWS.d/next/Library/2020-09-03-01-35-32.bpo-41696.zkYGre.rst b/Misc/NEWS.d/next/Library/2020-09-03-01-35-32.bpo-41696.zkYGre.rst
new file mode 100644
index 00000000000000..67bbbb857f18cb
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-09-03-01-35-32.bpo-41696.zkYGre.rst
@@ -0,0 +1 @@
+Fix handling of debug mode in :func:`asyncio.run`. This allows setting ``PYTHONASYNCIODEBUG`` or ``-X dev`` to enable asyncio debug mode when using :func:`asyncio.run`.
\ No newline at end of file