Fix formatting of coroutine-like objects (Cython coroutines etc)

Author: 1st1

asyncio/coroutines.py

@@ -261,6 +261,25 @@ def iscoroutine(obj):
 def _format_coroutine(coro):
     assert iscoroutine(coro)
 
+    if not hasattr(coro, 'cr_code') and not hasattr(coro, 'gi_code'):
+        # Most likely a Cython coroutine.
+        coro_name = getattr(coro, '__qualname__', coro.__name__)
+        coro_name = '{}()'.format(coro_name)
+
+        running = False
+        try:
+            running = coro.cr_running
+        except AttributeError:
+            try:
+                running = coro.gi_running
+            except AttributeError:
+                pass
+
+        if running:
+            return '{} running'.format(coro_name)
+        else:
+            return coro_name
+
     coro_name = None
     if isinstance(coro, CoroWrapper):
         func = coro.func

tests/test_events.py

@@ -25,6 +25,7 @@
     import tty
 
 import asyncio
+from asyncio import coroutines
 from asyncio import proactor_events
 from asyncio import selector_events
 from asyncio import sslproto
@@ -2380,6 +2381,36 @@ def check_source_traceback(h):
         h = loop.call_later(0, noop)
         check_source_traceback(h)
 
+    def test_coroutine_like_object_debug_formatting(self):
+        # Test that asyncio can format coroutines that are instances of
+        # collections.abc.Coroutine, but lack cr_core or gi_code attributes
+        # (such as ones compiled with Cython).
+
+        class Coro:
+            __name__ = 'AAA'
+
+            def send(self, v):
+                pass
+
+            def throw(self, *exc):
+                pass
+
+            def close(self):
+                pass
+
+            def __await__(self):
+                pass
+
+        coro = Coro()
+        self.assertTrue(asyncio.iscoroutine(coro))
+        self.assertEqual(coroutines._format_coroutine(coro), 'AAA()')
+
+        coro.__qualname__ = 'BBB'
+        self.assertEqual(coroutines._format_coroutine(coro), 'BBB()')
+
+        coro.cr_running = True
+        self.assertEqual(coroutines._format_coroutine(coro), 'BBB() running')
+
 
 class TimerTests(unittest.TestCase):