processutils python_exec arg cannot be None

[Brian Rosmaita]

Ran into this use case in Glance, where we may want to pass a configured path for python_exec in some cases, but otherwise want to let processutils handle it. Thus, we'd call

  processutils.execute(python_exec=conf.python_interp)

where conf.python_interp could be None. On the processutiils side, the python_exec parameter is handled like this [0]:

  python_exec = kwargs.pop('python_exec', sys.executable)

So for the glance use case, what happens is that when 'python_exec' is passed with value None, None becomes the local value of python_exec, which will not end well inside the execute() function. I can't think of an actual use case for having python_exec being None within the execute() function, so I propose that the line above be changed to:

  python_exec = kwargs.pop('python_exec', None) or sys.executable

This way, if the python_exec argument is missing or is None, processutils will use an appropriate executable, which I think is most likely how people think this argument behaves anyway (I know I did).

[0] https://opendev.org/openstack/oslo.concurrency/src/commit/95b9334cfab6849fbe47e2b118e5355af3675dba/oslo_concurrency/processutils.py#L332

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/oslo.concurrency/+/831432

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/oslo.concurrency/+/831432
Committed: https://opendev.org/openstack/oslo.concurrency/commit/a937c5562f7cca721972822d72ae7d2915bd5d52
Submitter: "Zuul (22348)"
Branch: master

commit a937c5562f7cca721972822d72ae7d2915bd5d52
Author: Brian Rosmaita <email address hidden>
Date: Tue Mar 1 12:50:33 2022 -0500

    Allow python_exec kwarg to be None

    processutils.execute() is documented to take a python_exec kwarg and
    default to using sys.executable if that argument isn't set. It is
    convenient (and more intuitive) for this behavior to also occur if
    the argument is present with value None.

    Closes-bug: #1962603
    Related-bug: #1962581
    Change-Id: I2e1f187feaf4bf9fbfaf04fce78efa0cba49fc07

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/oslo.concurrency 4.5.1 release.