Relax protobuf version

[cderici]

We recently bumped into a clash in our project juju/python-libjuju#914 between macaroonbakery and mysql-connector-python regarding the protobuf version. (see #76 (comment))

The main point of this PR is to drop the protobuf version ceiling which includes the dependency range that the mysql-connector-python is compatible with.

For this rev I needed to update a bunch of other stuff, including but not limited to moving things to python3.

I'm not entirely sure if the changes proposed in this PR is sufficient, appropriate or suitable for the goals of py-macaroon-bakery (I was able to confirm only a subset of the tests here passing). However, it does seem to work with python-libjuju (need to run more tests on that).

Last release of this project was in 2020, so I'm not sure if this project is still being maintained. So I'll be pointing our dependency to my local fork for the time being, unless you guys want to move this forward.

[petrutlucian94]

What aboutprotobuf>=3.4.0,<5.0 instead? If another dependency (e.g. python-mysql-connector) needs something more specific but within range, the pip resolver will take care of that.

We intend to use python-libmaas with Openstack Watcher but we're having issues with the upper constraints as it tries to use 4.24.3:

https://github.com/openstack/requirements/blob/e54dc19f590bd0ea74fd2d7ada3d0d1b3321260b/upper-constraints.txt#L377
https://review.opendev.org/c/openstack/watcher/+/898790

The conflict is caused by:
    macaroonbakery 1.3.1 depends on protobuf<4.0 and >=3.0.0
    The user requested (constraint) protobuf===4.24.3

[cderici]

I see your conflict, yeah I think it's a good suggestion, it might work for everyone 👍

[cderici]

Yeah I'm not sure why I gave this an upper bound anyways, you're right pip should take care of the specific boundaries, thanks for the suggestion @petrutlucian94!

[petrutlucian94]

@fabricematrat thanks a lot for merging this patch! Could you please push a new release to pypi?

[petrutlucian94]

@fabricematrat @cderici FYI, the PyPI package still uses the old requirement:

The conflict is caused by:
    macaroonbakery 1.3.2 depends on protobuf<4.0 and >=3.0.0

I think it's because the setup.py requirement needs to be updated as well:

py-macaroon-bakery/setup.py

Line 30 in 33baa19

'protobuf>=3.0.0,<4.0',

Here's another PR: #92

[cderici]

@petrutlucian94 Thanks so much for catching this, I was wondering what was going on, this explains it. Also thanks for opening the new PR, it's unfortunate that we'll need another patch release on pypi for that to get in.