| Message ID | 20170720162815.19802-3-ldoktor@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Jul 20, 2017 at 06:28:06PM +0200, Lukáš Doktor wrote: > The list object is mutable in python and potentially might modify other > object's arguments when used as default argument. Reproducer: > > >>> vm1 = QEMUMachine("qemu") > >>> vm2 = QEMUMachine("qemu") > >>> vm1._wrapper.append("foo") > >>> print vm2._wrapper > ['foo'] > > In this case the `args` is actually copied so it would be safe to keep > it, but it's not a good practice to keep it. > > Signed-off-by: Lukáš Doktor <ldoktor@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
On 07/20/2017 01:28 PM, Lukáš Doktor wrote: > The list object is mutable in python and potentially might modify other > object's arguments when used as default argument. Reproducer: > > >>> vm1 = QEMUMachine("qemu") > >>> vm2 = QEMUMachine("qemu") > >>> vm1._wrapper.append("foo") > >>> print vm2._wrapper > ['foo'] > > In this case the `args` is actually copied so it would be safe to keep > it, but it's not a good practice to keep it. > > Signed-off-by: Lukáš Doktor <ldoktor@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > scripts/qemu.py | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/scripts/qemu.py b/scripts/qemu.py > index 191c916..66fd863 100644 > --- a/scripts/qemu.py > +++ b/scripts/qemu.py > @@ -23,7 +23,7 @@ import qmp.qmp > class QEMUMachine(object): > '''A QEMU VM''' > > - def __init__(self, binary, args=[], wrapper=[], name=None, > + def __init__(self, binary, args=None, wrapper=None, name=None, > test_dir="/var/tmp", monitor_address=None, > socket_scm_helper=None, debug=False): > ''' > @@ -39,6 +39,10 @@ class QEMUMachine(object): > @param debug: enable debug mode (forwarded to QMP helper and such) > @note: Qemu process is not started until launch() is used. > ''' > + if args is None: > + args = [] > + if wrapper is None: > + wrapper = [] > if name is None: > name = "qemu-%d" % os.getpid() > if monitor_address is None: >
diff --git a/scripts/qemu.py b/scripts/qemu.py index 191c916..66fd863 100644 --- a/scripts/qemu.py +++ b/scripts/qemu.py @@ -23,7 +23,7 @@ import qmp.qmp class QEMUMachine(object): '''A QEMU VM''' - def __init__(self, binary, args=[], wrapper=[], name=None, + def __init__(self, binary, args=None, wrapper=None, name=None, test_dir="/var/tmp", monitor_address=None, socket_scm_helper=None, debug=False): ''' @@ -39,6 +39,10 @@ class QEMUMachine(object): @param debug: enable debug mode (forwarded to QMP helper and such) @note: Qemu process is not started until launch() is used. ''' + if args is None: + args = [] + if wrapper is None: + wrapper = [] if name is None: name = "qemu-%d" % os.getpid() if monitor_address is None: