CI will fail on its next run: ruff is unpinned and 0.16 changed its default rules (11 errors)

[joeljose]

Severity: High. Both CI jobs break with no code change.

requirements-dev.txt has ruff>=0.4.0,<1, the repo has no ruff config, and both CI jobs (test and test-gpu) rebuild their images from scratch on every push.

ruff	ruff check . on main (39e90eb)
0.15.7	All checks passed
0.16.9 (what a fresh build installs today)	11 errors: PLW1510 ×6 (subprocess.run without check), I001 ×3, SIM113, RUF059

The last green run was 21 Mar 2026.

Suggested fix

• Pin the dev tools exactly (ruff==0.15.7, pytest==8.4.2) and upgrade them on purpose (Dependabot).
• Add pyproject.toml with an explicit rule set:

  [tool.ruff.lint]
  select = ["E", "F", "W", "I"]

  visualmic.py is tab-indented while the tests use spaces. Pick one style (and W191 if tabs are kept) so the formatter and linter agree.
• Optionally run a weekly scheduled CI job to catch drift early.

Acceptance criteria

• Lint passes on a fresh image build, and the tool versions are pinned.