From d1477074458ef1de3762dd41f45d2b5a5be08c0f Mon Sep 17 00:00:00 2001
From: Lidi Zheng <lidiz@google.com>
Date: Wed, 26 Feb 2020 11:01:41 -0800
Subject: [PATCH 1/2] Make get_stack accept ag_frame

---
 Lib/asyncio/base_tasks.py | 13 ++++++++++---
 Lib/test/test_asyncgen.py | 15 +++++++++++++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/Lib/asyncio/base_tasks.py b/Lib/asyncio/base_tasks.py
index e2da462fde7400..09bb171a2ce750 100644
--- a/Lib/asyncio/base_tasks.py
+++ b/Lib/asyncio/base_tasks.py
@@ -24,11 +24,18 @@ def _task_repr_info(task):
 
 def _task_get_stack(task, limit):
     frames = []
-    try:
-        # 'async def' coroutines
+    if hasattr(task._coro, 'cr_frame'):
+        # case 1: 'async def' coroutines
         f = task._coro.cr_frame
-    except AttributeError:
+    elif hasattr(task._coro, 'gi_frame'):
+        # case 2: legacy coroutines
         f = task._coro.gi_frame
+    elif hasattr(task._coro, 'ag_frame'):
+        # case 3: async generators
+        f = task._coro.ag_frame
+    else:
+        # case 4: unknown objects
+        f = None
     if f is not None:
         while f is not None:
             if limit is not None:
diff --git a/Lib/test/test_asyncgen.py b/Lib/test/test_asyncgen.py
index fb6321d2264f31..62bf8774166529 100644
--- a/Lib/test/test_asyncgen.py
+++ b/Lib/test/test_asyncgen.py
@@ -1191,5 +1191,20 @@ async def run():
 
         self.loop.run_until_complete(run())
 
+    def test_async_gen_aclose_compatible_with_get_stack(self):
+        async def async_generator():
+            yield object()
+
+        async def run():
+            ag = async_generator()
+            asyncio.create_task(ag.aclose())
+            tasks = asyncio.all_tasks()
+            for task in tasks:
+                # No AttributeError raised
+                task.get_stack()
+
+        self.loop.run_until_complete(run())
+
+
 if __name__ == "__main__":
     unittest.main()

From 480dbda18c0531f1230d2d7ed42e1da0b8c181d2 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Thu, 27 Feb 2020 18:21:08 +0000
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../NEWS.d/next/Library/2020-02-27-18-21-07.bpo-39764.wqPk68.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2020-02-27-18-21-07.bpo-39764.wqPk68.rst

diff --git a/Misc/NEWS.d/next/Library/2020-02-27-18-21-07.bpo-39764.wqPk68.rst b/Misc/NEWS.d/next/Library/2020-02-27-18-21-07.bpo-39764.wqPk68.rst
new file mode 100644
index 00000000000000..d61db2ea221f26
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-02-27-18-21-07.bpo-39764.wqPk68.rst
@@ -0,0 +1 @@
+Fix AttributeError when calling get_stack on a PyAsyncGenObject Task
\ No newline at end of file