CI/build should fail fast if no tags are available

[jsoref]

This was reported a while ago... If you have a partial clone / a clone without tags / a repository that doesn't have tags, then the version file that's generated isn't compatible w/ the expectations of version.py:

    version = '0.1.dev1+gedcff4f'

guess that is setuptools_scm not being able to determine the right version number.

possible reasons:

• you did not do a full git clone, but only fetched the latest state (thus it has not enough history information). a shallow clone will not work.
• you also need to check out the correct tag, e.g. git checkout 1.2.0
• the run pip install -e . and borg -V and it should tell 1.2.0.

Originally posted by @ThomasWaldmann in #6510 (comment)

---

Today, builds take >5 mins to fail in CI which is a lot of time for practically no benefit (you can't access the compiled content, you're just wasting GitHub resources and a build slot)

[jsoref]

https://github.com/jsoref/borg/actions/runs/3903581871

Triggered via push 12 minutes ago
@jsoref pushed d58e3d6 spell-check
Status Failure
Total duration 6m 56s
Artifacts –

[ThomasWaldmann]

Hmm, not sure what this issue is about.

It is known that a shallow git clone is not enough to make setuptools_scm happy, that's why we do a full clone.

So, what do you suggest?

[jsoref]

One of the first steps in the build should check for something it needs and fail early.

It might be as simple as:

if ! git describe --tags >/dev/null 2>/dev/null; then
  echo "Sorry, shallow clones / clones without tags aren't supported -- please see {documentation ref} for more information" 2>&1
  exit 1
fi

[RonnyPfannschmidt]

There are some ways to make it error,

[ThomasWaldmann]

Guess the existence of git tags is not a strict requirement if SETUPTOOLS_SCM_PRETEND_VERSION is given via the environment.

Also, if somebody downloads a borg release from pypi, our setup code also won't require a git repo, of course.

So, not sure what to change where exactly to improve the current behaviour.

[jsoref]

Something in (or under, e.g. in setup.py) https://github.com/borgbackup/borg/blob/d58e3d67574742037e0d63b5807ef8a77836b5cf/scripts/msys2-build could quickly check for that env var or the other things and fail fast.

The goal is to avoid compiling most of the system only to fail at the very end.

[RayyanAnsari]

https://github.com/jsoref/borg/actions/runs/3903581871

Triggered via push 12 minutes ago @jsoref pushed d58e3d6 spell-check Status Failure Total duration 6m 56s Artifacts –

I'm not sure why that test run has failed, it works fine on the main branch because it uses:

      - uses: actions/checkout@v3
        with:
          fetch-depth: 0

to get the full commit history.

[jsoref]

When I fork, I delete all tags. So there aren't any: https://github.com/jsoref/borg/tags