ci: add an alpha input to the Bump Version workflow

[TheGupta2012]

Opens a development cycle, the step that has no automation behind it today.

Bump Version writes a plain version computed from the latest release, which is
right for a release commit. Nothing re-adds a suffix afterwards, so the repository
sits on a plain version between releases. That is what produced the recent
breakage: pyproject.toml held 1.1.0 while 1.1.0 was already on PyPI, so the
stamper returned 1.1.0-a.0 on every run, and the wheels from the first run made
every later run collide.

This adds an alpha checkbox to the same workflow, off by default. With it
checked, the bumped version gets an -alpha suffix and CITATION.cff is left
alone, since an alpha is not a release and the last one stays the citable
artifact. Unchecked, the workflow behaves exactly as before.

The suffix is what carries a .pre segment for get_prelease_version to
increment, so successive pre-releases stamp a0, a1, a2 rather than a0 forever.
Because the bump is computed from the latest release, the result always sits
above it, and a pre-release built from it cannot collide with a version already
live on PyPI.

The suffix logic lives behind a --alpha flag on bin/bump_version.py. It
appends to Version(...).base_version, which drops any suffix already present
rather than producing 1.2.0-alpha-alpha.

Verified locally

Replayed the workflow's shell block against the real scripts, for every input
combination:

alpha=false patch  -> 1.1.1          changed: pyproject.toml CITATION.cff
alpha=false minor  -> 1.2.0          changed: pyproject.toml CITATION.cff
alpha=false major  -> 2.0.0          changed: pyproject.toml CITATION.cff
alpha=true  patch  -> 1.1.1-alpha    changed: pyproject.toml
alpha=true  minor  -> 1.2.0-alpha    changed: pyproject.toml
alpha=true  major  -> 2.0.0-alpha    changed: pyproject.toml

CITATION.cff with alpha=true : version: 1.1.0 (untouched)
CITATION.cff with alpha=false: version: 1.2.0

running --alpha twice writes 1.2.0-alpha both times
1.2.0-alpha parses as PEP 440 1.2.0a0
pre-release run 1 -> 1.2.0-a.0, run 2 -> 1.2.0-a.1

Note

Dispatching with the same inputs twice produces no diff, so the commit step fails
with "nothing to commit". That behaviour is unchanged by this PR.

[argus-eye]

Argus review

Auto-review is off for this repo. Tick the box below to run a review on this PR.

• Trigger Argus review

Estimated cost

• Files changed: 3
• Diff lines (±): 90
• Historical avg: ~243.6k tokens · ~$0.95 · across last 10 review(s)

Tip: you can also comment @argus-eye review at any time.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on this repository. Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 4961c06d-97ed-48f6-a9f2-8f56b7811443

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!