Re: [Qemu-devel] [PATCH v3 2/3] qemu.py: Add QEMUMachine.exitcode() method

[Eduardo Habkost]

On Mon, May 29, 2017 at 06:53:47PM +0200, Markus Armbruster wrote:
> Eduardo Habkost <address@hidden> writes:
> 
> > Allow the exit code of QEMU to be queried by scripts.
> >
> > Signed-off-by: Eduardo Habkost <address@hidden>
> > ---
> >  scripts/qemu.py | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/scripts/qemu.py b/scripts/qemu.py
> > index 16934f1e02..ebe1c4b919 100644
> > --- a/scripts/qemu.py
> > +++ b/scripts/qemu.py
> > @@ -88,6 +88,10 @@ class QEMUMachine(object):
> >      def is_running(self):
> >          return self._popen and (self._popen.returncode is None)
> >  
> > +    def exitcode(self):
> > +        if self._popen:
> > +            return self._popen.returncode
> > +
> 
> Falling off the function's end returns None.  Do we really want to rely
> on that?
> 
> For what it's worth, I checked the Python Language Reference, found it
> less than clear, so I tried it out, too.

I agree that the intent may not be clear when looking at the
code.  I can squash this in:

diff --git a/scripts/qemu.py b/scripts/qemu.py
index ebe1c4b919..bf00eddab8 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -89,8 +89,9 @@ class QEMUMachine(object):
         return self._popen and (self._popen.returncode is None)
 
     def exitcode(self):
-        if self._popen:
-            return self._popen.returncode
+        if not self._popen:
+            return None
+        return self._popen.returncode
 
     def get_pid(self):
         if not self.is_running():

-- 
Eduardo