Re: [Qemu-devel] [Qemu-block] [PATCH 3/4] scripts/qemu.py: tiny enhancement for event_wiat

[John Snow <jsnow@redhat.com>]

On 11/28/2017 02:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> - add comment
> - allow int timeout and disallow bool (which has special
>   meaning for pull_event())
> - remove unreachable 'return None'
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  scripts/qemu.py | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index 9bfdf6d37d..8763335254 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -291,7 +291,13 @@ class QEMUMachine(object):
>          branch processing on match's value None
>             {"foo": {"bar": 1}} matches {"foo": None}
>             {"foo": {"bar": 1}} does not matches {"foo": {"baz": None}}
> +
> +        @raise QMPTimeoutError: If timeout period elapses.
> +        @raise QMPConnectError: If some other error occurred.
>          '''
> +
> +        assert isinstance(timeout, float) or isinstance(timeout, int)
> +
>          def event_match(event, match=None):
>              if match is None:
>                  return True
> @@ -316,13 +322,11 @@ class QEMUMachine(object):
>  
>          # Poll for new events
>          while True:
> -            event = self._qmp.pull_event(wait=timeout)
> +            event = self._qmp.pull_event(wait=float(timeout))

Before this patch you *could* ask for no timeout, and this would block
waiting for an event. After, you can't.

Are you making the argument that it is *never* correct to ask for no
timeout?

>              if (event['event'] == name) and event_match(event, match):
>                  return event
>              self._events.append(event)
>  
> -        return None
> -
>      def get_log(self):
>          '''
>          After self.shutdown or failed qemu execution, this returns the output
>