Re: [RFC PATCH 7/8] tests/pytest: Add a function for extracting files from an archive

[Thomas Huth]

On 12/07/2024 11.14, Daniel P. Berrangé wrote:
> On Thu, Jul 11, 2024 at 01:55:45PM +0200, Thomas Huth wrote:
> > Some Avocado-based tests use the "archive" module from avocado.utils
> > to extract files from an archive. To be able to use these tests
> > without Avocado, we have to provide our own function for extracting
> > files. Fortunately, there is already the tarfile module that will
> > provide us with this functionality, so let's just add a nice wrapper
> > function around that.
> >
> > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > ---
> >   tests/pytest/qemu_pytest/utils.py | 21 +++++++++++++++++++++
> >   1 file changed, 21 insertions(+)
> >   create mode 100644 tests/pytest/qemu_pytest/utils.py
> >
> > diff --git a/tests/pytest/qemu_pytest/utils.py 
> > b/tests/pytest/qemu_pytest/utils.py
> > new file mode 100644
> > index 0000000000..4eb5e5d5e5
> > --- /dev/null
> > +++ b/tests/pytest/qemu_pytest/utils.py
> > @@ -0,0 +1,21 @@
> > +# Utilities for python-based QEMU tests
> > +#
> > +# Copyright 2024 Red Hat, Inc.
> > +#
> > +# Authors:
> > +#  Thomas Huth <thuth@redhat.com>
> > +#
> > +# This work is licensed under the terms of the GNU GPL, version 2 or
> > +# later.  See the COPYING file in the top-level directory.
> > +
> > +import tarfile
> > +
> > +def archive_extract(archive, dest_dir, member=None):
> > +    with tarfile.open(archive) as tf:
> > +        if hasattr(tarfile, 'data_filter'):
>
> Not convinced this is still needed. The python docs don't say anything
> about 'data_filter' being introduced after 3.0, so can likely
> assume it always exists.

According to https://docs.python.org/3/library/tarfile.html :

"Extraction filters were added to Python 3.12, but may be backported to 
older versions as security updates. To check whether the feature is 
available, use e.g. hasattr(tarfile, 'data_filter') rather than checking the 
Python version."

And it seems to be missing in Python 3.7, indeed:

 https://docs.python.org/3.7/library/tarfile.html

So as long as we still support this old version, I think I've got to keep 
this check.

 Thomas