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 <ldok...@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4...@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:
