Use asyncio.isfuture instead of isinstance(Future)

uvloop/chain_futs.pyx

@@ -45,9 +45,9 @@ cdef _chain_future(source, destination):
     If destination is cancelled, source gets cancelled too.
     Compatible with both asyncio.Future and concurrent.futures.Future.
     """
-    if not isinstance(source, (aio_Future, cc_Future)):
+    if not isfuture(source) and not isinstance(source, cc_Future):
         raise TypeError('A future is required for source argument')
-    if not isinstance(destination, (aio_Future, cc_Future)):
+    if not isfuture(destination) and not isinstance(destination, cc_Future):
         raise TypeError('A future is required for destination argument')
 
     source_loop = None
@@ -58,18 +58,16 @@ cdef _chain_future(source, destination):
 
     if source_type is uvloop_Future:
         source_loop = (<BaseFuture>source)._loop
-    elif source_type is not cc_Future and \
-            isinstance(source, aio_Future):
+    elif source_type is not cc_Future and isfuture(source):
         source_loop = source._loop
 
     if dest_type is uvloop_Future:
         dest_loop = (<BaseFuture>destination)._loop
-    elif dest_type is not cc_Future and \
-            isinstance(destination, aio_Future):
+    elif dest_type is not cc_Future and isfuture(destination):
         dest_loop = destination._loop
 
     def _set_state(future, other):
-        if isinstance(future, aio_Future):
+        if isfuture(future):
             _copy_future_state(other, future)
         else:
             _set_concurrent_future_state(future, other)
@@ -95,7 +93,7 @@ def _wrap_future(future, *, loop=None):
     # Don't use this function -- it's here for tests purposes only
     # and can be removed in future versions of uvloop.
 
-    if isinstance(future, aio_Future):
+    if isfuture(future):
         return future
     assert isinstance(future, cc_Future), \
         'concurrent.futures.Future is expected, got {!r}'.format(future)

uvloop/handles/basetransport.pyx

@@ -200,7 +200,7 @@ cdef class UVBaseTransport(UVSocketHandle):
         (<Server>server)._attach()
 
     cdef inline _set_waiter(self, object waiter):
-        if waiter is not None and not isinstance(waiter, aio_Future):
+        if waiter is not None and not isfuture(waiter):
             raise TypeError(
                 'invalid waiter object {!r}, expected asyncio.Future'.
                     format(waiter))

uvloop/includes/stdlib.pxi

@@ -37,6 +37,7 @@ cdef aio_BaseProtocol = asyncio.BaseProtocol
 cdef aio_Protocol = asyncio.Protocol
 cdef aio_SSLProtocol = asyncio.sslproto.SSLProtocol
 cdef aio_debug_wrapper = asyncio.coroutines.debug_wrapper
+cdef aio_isfuture = getattr(asyncio, 'isfuture', None)
 
 cdef col_deque = collections.deque
 cdef col_Iterable = collections.Iterable

uvloop/loop.pyx

@@ -40,6 +40,13 @@ include "includes/stdlib.pxi"
 include "errors.pyx"
 
 
+cdef isfuture(obj):
+    if aio_isfuture is None:
+        return isinstance(obj, aio_Future)
+    else:
+        return getattr(obj, '_asyncio_future_blocking', None) is not None
+
+
 @cython.no_gc_clear
 cdef class Loop:
     def __cinit__(self):
@@ -1115,7 +1122,7 @@ cdef class Loop:
         """
         self._check_closed()
 
-        new_task = not isinstance(future, aio_Future)
+        new_task = not isfuture(future)
         future = aio_ensure_future(future, loop=self)
         if new_task:
             # An exception is raised if the future didn't complete, so there

uvloop/task.pyx

@@ -152,7 +152,7 @@ cdef class BaseTask(BaseFuture):
                 else:
                     self._raise_yield(result)
 
-            elif result_type is aio_Future or isinstance(result, aio_Future):
+            elif result_type is aio_Future or isfuture(result):
                 # Yielded Future must come from Future.__iter__().
                 if result._loop is not self._loop:
                     self._raise_wrong_loop(result)