Open Stack

Hello,

The recent release of tox 1.7.2 has fixed the {posargs} interpolation
issues we had with newer tox which forced us to be pinned to tox==1.6.1.
Before we can remove the pin and start telling people to use latest tox
we need to address a new default behavior in tox.

New tox sets a random PYTHONHASHSEED value by default. Arguably this is
a good thing as it forces you to write code that handles unknown hash
seeds, but unfortunately many projects' unittests don't currently deal
with this very well. A work around is to hard set a PYTHONHASHSEED of 0
in tox.ini files. I have begun to propose these changes to the projects
that I have tested and found to not handle random seeds. It would be
great if we could get these reviewed and merged so that infra can update
the version of tox used on our side.

I probably won't be able to test every single project and propose fixes
with backports to stable branches for everything. It would be a massive
help if individual projects tested and proposed fixes as necessary too
(these changes will need to be backported to stable branches). You can
test by running `tox -epy27` in your project with tox version 1.7.2. If
that fails add PYTHONHASHSEED=0 as in
https://review.openstack.org/#/c/109700/ and rerun `tox -epy27` to
confirm that succeeds.

This will get us over the immediate hump of the tox upgrade, but we
should also start work to make our tests run with random hashes. This
shouldn't be too hard to do as it will be a self gating change once
infra is able to update the version of tox used in the gate. Most of the
issues appear related to dict entry ordering. I have gone ahead and
created https://bugs.launchpad.net/cinder/+bug/1348818 to track this
work.

Thank you,
Clark