diff options
Diffstat (limited to 'Lib/asyncio')
| -rw-r--r-- | Lib/asyncio/futures.py | 12 | ||||
| -rw-r--r-- | Lib/asyncio/tasks.py | 7 |
2 files changed, 14 insertions, 5 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. diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py index 0cca8e3..3e200f6 100644 --- a/Lib/asyncio/tasks.py +++ b/Lib/asyncio/tasks.py @@ -249,7 +249,8 @@ class Task(futures.Future): self.set_exception(exc) raise else: - if isinstance(result, futures.Future): + blocking = getattr(result, '_asyncio_future_blocking', None) + if blocking is not None: # Yielded Future must come from Future.__iter__(). if result._loop is not self._loop: self._loop.call_soon( @@ -257,8 +258,8 @@ class Task(futures.Future): RuntimeError( 'Task {!r} got Future {!r} attached to a ' 'different loop'.format(self, result))) - elif result._blocking: - result._blocking = False + elif blocking: + result._asyncio_future_blocking = False result.add_done_callback(self._wakeup) self._fut_waiter = result if self._must_cancel: |