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. The same issue applies in
inherited qtest module.
Signed-off-by: Lukáš Doktor <ldok...@redhat.com>
Reviewed-by: Eduardo Habkost <ehabk...@redhat.com>
Reviewed-by: John Snow <js...@redhat.com>
---
scripts/qemu.py | 6 +++++-
scripts/qtest.py | 2 +-
2 files changed, 6 insertions(+), 2 deletions(-)
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/qtest.py b/scripts/qtest.py
index d5aecb5..ab183c0 100644
--- a/scripts/qtest.py
+++ b/scripts/qtest.py
@@ -79,7 +79,7 @@ class QEMUQtestProtocol(object):
class QEMUQtestMachine(qemu.QEMUMachine):
'''A QEMU VM'''
- def __init__(self, binary, args=[], name=None, test_dir="/var/tmp",
+ def __init__(self, binary, args=None, name=None, test_dir="/var/tmp",
socket_scm_helper=None):
if name is None:
name = "qemu-%d" % os.getpid()
--
2.9.4
