diff options
Diffstat (limited to 'Lib/asyncio/futures.py')
| -rw-r--r-- | Lib/asyncio/futures.py | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py index 1feba4d..edc13dc 100644 --- a/Lib/asyncio/futures.py +++ b/Lib/asyncio/futures.py @@ -134,7 +134,15 @@ class Future: _loop = None _source_traceback = None - _blocking = False # proper use of future (yield vs yield from) + # This field is used for a dual purpose: + # - Its presence is a marker to declare that a class implements + # the Future protocol (i.e. is intended to be duck-type compatible). + # The value must also be not-None, to enable a subclass to declare + # that it is not compatible by setting this to None. + # - It is set by __iter__() below so that Task._step() can tell + # the difference between `yield from Future()` (correct) vs. + # `yield Future()` (incorrect). + _asyncio_future_blocking = False _log_traceback = False # Used for Python 3.4 and later _tb_logger = None # Used for Python 3.3 only @@ -357,7 +365,7 @@ class Future: def __iter__(self): if not self.done(): - self._blocking = True + self._asyncio_future_blocking = True yield self # This tells Task to wait for completion. assert self.done(), "yield from wasn't used with future" return self.result() # May raise too. |