Python/aqmp: fix type definitions for mypy 0.920

0.920 (Released 2021-12-15) is not entirely happy with the
way that I was defining _FutureT:

qemu/aqmp/protocol.py:601: error: Item "object" of the upper bound
"Optional[Future[Any]]" of type variable "_FutureT" has no attribute
"done"

Update it with something a little mechanically simpler that works better
across a wider array of mypy versions.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20220110191349.1841027-3-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

diff --git a/python/qemu/aqmp/protocol.py b/python/qemu/aqmp/protocol.py
index 5190b33..c4fbe35 100644 (file)
--- a/python/qemu/aqmp/protocol.py
+++ b/python/qemu/aqmp/protocol.py
@@ -43,8 +43,8 @@ from .util import (
 
 
 T = TypeVar('T')
+_U = TypeVar('_U')
 _TaskFN = Callable[[], Awaitable[None]]  # aka ``async def func() -> None``
-_FutureT = TypeVar('_FutureT', bound=Optional['asyncio.Future[Any]'])
 
 
 class Runstate(Enum):
@@ -591,7 +591,8 @@ class AsyncProtocol(Generic[T]):
         """
         Fully reset this object to a clean state and return to `IDLE`.
         """
-        def _paranoid_task_erase(task: _FutureT) -> Optional[_FutureT]:
+        def _paranoid_task_erase(task: Optional['asyncio.Future[_U]']
+                                 ) -> Optional['asyncio.Future[_U]']:
             # Help to erase a task, ENSURING it is fully quiesced first.
             assert (task is None) or task.done()
             return None if (task and task.done()) else task