chore: drop Python 3.9 from CI matrix and pyproject

[luckyPipewrench]

Python 3.9 reached upstream end-of-life on 2025-10-31. Recent test framework releases (pytest 9.0+) have dropped 3.9 support, which is currently blocking the routine pytest update PR (#21) on the 3.9 leg of the matrix while the other four Python versions pass cleanly.

Changes: drop 3.9 from the workflow matrix, bump requires-python to >=3.10, bump mypy python_version to 3.10, remove the Python 3.9 trove classifier.

Effect on users: pip continues to install older releases of pipelock-verify on Python 3.9 environments via standard requires-python resolution. New releases require Python 3.10 or newer.

After this merges, #21 can be force-merged (its tests will now skip the 3.9 leg that no longer exists in the matrix), or closed in favor of letting Renovate re-propose the pytest bump under the new 10-day cooldown policy.

Summary by CodeRabbit

• Chores
  • Minimum Python version requirement updated to 3.10+.
  • Testing extended to Python 3.10, 3.11, 3.12, and 3.13 with 3.9 support dropped.

[coderabbitai]

📝 Walkthrough

Walkthrough

Project minimum Python version is raised from 3.9 to 3.10 across package metadata, classifiers, mypy type-checking, and CI test matrix. Python 3.9 is removed from all test targets and declared supported versions.

Changes

Python 3.10 Minimum Version Requirement

Layer / File(s)	Summary
Python 3.10 minimum across project configuration and CI pyproject.toml, .github/workflows/ci.yml	Project minimum Python version requirement is raised from 3.9 to 3.10 in requires-python, classifiers, and mypy configuration; CI test matrix is updated to remove Python 3.9 and run tests only on 3.10, 3.11, 3.12, and 3.13.

🎯 1 (Trivial) | ⏱️ ~3 minutes

A rabbit hops forth with glee, 🐰
Python 3.9 no more to be,
Version 3.10 takes its place,
In config and CI without a trace!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and clearly describes the main changes: dropping Python 3.9 from both the CI matrix and pyproject configuration.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/drop-python-3.9

---

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 and usage tips.}

[coderabbitai]

🧹 Nitpick comments (1)

pyproject.toml (1)

84-84: ⚡ Quick win

Align Ruff's target-version with the Python 3.10 baseline.

Ruff is configured with target-version = "py39" (line 77) while requires-python = ">=3.10" and python_version = "3.10" are both set to 3.10. This mismatch causes Ruff's lint and upgrade behavior to target an older Python version than declared.

Proposed change

 [tool.ruff]
 line-length = 100
-target-version = "py39"
+target-version = "py310"

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@pyproject.toml` at line 84, Ruff's configured target-version ("py39") doesn't
match the declared Python baseline (requires-python = ">=3.10" and
python_version = "3.10"); update the Ruff configuration key target-version to
"py310" so Ruff's linting and upgrade rules align with the project's Python 3.10
baseline (look for the target-version setting in the pyproject.toml alongside
requires-python and python_version).

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@pyproject.toml`:
- Line 84: Ruff's configured target-version ("py39") doesn't match the declared
Python baseline (requires-python = ">=3.10" and python_version = "3.10"); update
the Ruff configuration key target-version to "py310" so Ruff's linting and
upgrade rules align with the project's Python 3.10 baseline (look for the
target-version setting in the pyproject.toml alongside requires-python and
python_version).

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6a1c84a2-dba6-4192-b810-cd938bee437e

📥 Commits

Reviewing files that changed from the base of the PR and between 6e5016b and 2e59a48.

📒 Files selected for processing (2)

• .github/workflows/ci.yml
• pyproject.toml