Confirmed the sha256, deferring merge to maintainers

Oops. Just noticed this is DRAFT.

Ok, when testing it locally it just build with ~cpp, that's why it worked.

I have added [email protected] and [email protected] (which is needed by protobuf) as well.

The cpp variant was deprecated starting [email protected] (see Release Notes and ReadMe).
Is restricting the variant enough for this? py-tensorflow for example depends on py-protobuf+cpp

This should be ready to review now.

@spackbot run pipeline

I've started that pipeline for you!

Thanks for updating this! I was going to add it in #36711 but chickened out when I saw that bazel might be required to build from source: protocolbuffers/protobuf#12390

So is bazel required or not? My understanding is that the PyPI source code (which we use) doesn't require bazel, but also doesn't support cpp, only upb/python. So if someone really wanted cpp, they would have to build from the git repo and use bazel. Is that correct?

py-tensorflow for example depends on py-protobuf+cpp

In all honesty, the TF package is a series of hacks built on top of hacks to get things working. The docs say it depends on protobuf but doesn't specify whether that's the Python lib or the C++ lib so we added both. And things start to break if those aren't the same version, which I think is why we added +cpp. So feel free to make changes because you likely know about as much as I do how things are actually supposed to work. As long as CI still passes I'm happy.

Wondering if we should replace +cpp with a multi-value variant like implementation=(upb|cpp|python). We can mark each value as limited to a particular range of versions.

bazel is listed as requirement, but the package builds fine without it. So I think your analysis is correct.
I actually don't know much about protobuf and just wanted to update it because of py-pip.

For the multi-value variant approach. At the moment I don't see any advantage in it.

The advantage would be that they can be marked as mutually exclusive. Of course, if no one wants or needs upb support and it's only +cpp or ~cpp as options, it doesn't make much of a difference.

P.S. TF no longer requires protobuf+cpp.

We can add support for upb in a future PR if someone actually needs it.