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Date: Thu, 20 Jul 2017 15:19:24 -0300
From: Eduardo Habkost <ehabkost@redhat.com>
Message-ID: <20170720181924.GS2757@localhost.localdomain>
References: <20170720162815.19802-1-ldoktor@redhat.com>
	<20170720162815.19802-3-ldoktor@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 02/11] qemu.py: Avoid dangerous arguments
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To: =?utf-8?B?THVrw6HFoQ==?= Doktor <ldoktor@redhat.com>
Cc: apahim@redhat.com, qemu-devel@nongnu.org, famz@redhat.com, armbru@redhat.com, mreitz@redhat.com

On Thu, Jul 20, 2017 at 06:28:06PM +0200, Luk=C3=A1=C5=A1 Doktor wrote:
> The list object is mutable in python and potentially might modify other
> object's arguments when used as default argument. Reproducer:
>=20
>     >>> vm1 =3D QEMUMachine("qemu")
>     >>> vm2 =3D QEMUMachine("qemu")
>     >>> vm1._wrapper.append("foo")
>     >>> print vm2._wrapper
>     ['foo']
>=20
> 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.
>=20
> Signed-off-by: Luk=C3=A1=C5=A1 Doktor <ldoktor@redhat.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

--=20
Eduardo