On Wed, Aug 4, 2021 at 5:39 AM Vladimir Sementsov-Ogievskiy <
vsement...@virtuozzo.com> wrote:
> In superclass __enter__ method is defined with return value type hint
> 'QEMUMachine'. So, mypy thinks that return value of VM.__enter__ is
> QEMUMachine. Let's redefine __enter__ in VM class, to give it correct
> type hint.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> Reviewed-by: Max Reitz <mre...@redhat.com>
> ---
> tests/qemu-iotests/iotests.py | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
> index 89663dac06..025e288ddd 100644
> --- a/tests/qemu-iotests/iotests.py
> +++ b/tests/qemu-iotests/iotests.py
> @@ -568,6 +568,10 @@ def remote_filename(path):
> class VM(qtest.QEMUQtestMachine):
> '''A QEMU VM'''
>
> + # Redefine __enter__ with proper type hint
> + def __enter__(self) -> 'VM':
> + return self
> +
> def __init__(self, path_suffix=''):
> name = "qemu%s-%d" % (path_suffix, os.getpid())
> super().__init__(qemu_prog, qemu_opts, name=name,
> --
> 2.29.2
>
First and foremost:
Reviewed-by: John Snow <js...@redhat.com>
Acked-by: John Snow <js...@redhat.com>
A more durable approach might be to annotate QEMUMachine differently such
that subclasses get the right types automatically. See if this following
snippet works instead of adding a new __enter__ method.
diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py
index 971ed7e8c6a..2e410103569 100644
--- a/python/qemu/machine/machine.py
+++ b/python/qemu/machine/machine.py
@@ -36,6 +36,7 @@
Sequence,
Tuple,
Type,
+ TypeVar,
)
from qemu.qmp import ( # pylint: disable=import-error
@@ -73,6 +74,9 @@ class AbnormalShutdown(QEMUMachineError):
"""
+_T = TypeVar('_T', bound='QEMUMachine')
+
+
class QEMUMachine:
"""
A QEMU VM.
@@ -166,7 +170,7 @@ def __init__(self,
self._remove_files: List[str] = []
self._user_killed = False
- def __enter__(self) -> 'QEMUMachine':
+ def __enter__(self: _T) -> _T:
return self
def __exit__(self,
@@ -182,8 +186,8 @@ def add_monitor_null(self) -> None:
self._args.append('-monitor')
self._args.append('null')
- def add_fd(self, fd: int, fdset: int,
- opaque: str, opts: str = '') -> 'QEMUMachine':
+ def add_fd(self: _T, fd: int, fdset: int,
+ opaque: str, opts: str = '') -> _T:
"""
Pass a file descriptor to the VM
"""
