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

[Thomas Huth <thuth@redhat.com>]

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