Re: [PATCH 05/10] python/machine: Disable pylint warning for open() in _pre_launch

[Wainer dos Santos Moschetta]

Hi,

On 5/12/21 6:46 PM, John Snow wrote:
> Shift the open() call later so that the pylint pragma applies *only* to
> that one open() call. Add a note that suggests why this is safe: the
> resource is unconditionally cleaned up in _post_shutdown().


You can also put it in a pylint disable/enable block. E.g.:

    # pylint: disable=consider-using-with

    self._qemu_log_file = open(self._qemu_log_path, 'wb')

    # pylint: enable=consider-using-with

However I don't know if this is bad practice. :)

Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>

> _post_shutdown is called after failed launches (see launch()), and
> unconditionally after every call to shutdown(), and therefore also on
> __exit__.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>   python/qemu/machine.py | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/python/qemu/machine.py b/python/qemu/machine.py
> index c13ff9b32bf..8f86303b48f 100644
> --- a/python/qemu/machine.py
> +++ b/python/qemu/machine.py
> @@ -308,7 +308,6 @@ def _pre_launch(self) -> None:
>           self._temp_dir = tempfile.mkdtemp(prefix="qemu-machine-",
>                                             dir=self._test_dir)
>           self._qemu_log_path = os.path.join(self._temp_dir, self._name + 
> ".log")
> -        self._qemu_log_file = open(self._qemu_log_path, 'wb')
>   
>           if self._console_set:
>               self._remove_files.append(self._console_address)
> @@ -323,6 +322,11 @@ def _pre_launch(self) -> None:
>                   nickname=self._name
>               )
>   
> +        # NOTE: Make sure any opened resources are *definitely* freed in
> +        # _post_shutdown()!
> +        # pylint: disable=consider-using-with
> +        self._qemu_log_file = open(self._qemu_log_path, 'wb')
> +
>       def _post_launch(self) -> None:
>           if self._qmp_connection:
>               self._qmp.accept()