[FredM67]

Problem

A hand-written .git/hooks/pre-commit occupied the hook slot on my machine and never chained to the pre-commit framework. Two consequences:

• Everything declared in .pre-commit-config.yaml — no-commit-to-branch, clang-format, trailing-whitespace, end-of-file-fixer, mixed-line-ending — was silently inert locally.
• The hook stamped @date / @copyright on every staged .cpp/.h, whether or not the file had actually been edited. Any git add -A turned into a spray of one-line date bumps. On feat: left-aligned ADC and circular channel list (#121) #127 that was 7 files of pure churn, all of them conflict bait against feature/remote-loads.

Change

• scripts/hooks/update-metadata.sh — the same logic, tracked and fixed. It stamps only when the staged diff contains a change other than the metadata lines themselves; a metadata-only change is restored from HEAD instead. Newly added files always stamp. Like clang-format, it rewrites the file and fails rather than calling git add itself (staging from inside a hook interferes with pre-commit's stash handling).
• .pre-commit-config.yaml — registers it as a local hook and adds ci: skip: [update-metadata], so pre-commit.ci never stamps headers with the build date.
• CONTRIBUTING.md — documents the hook and the CI skip.

Testing

Exercised all three paths against a tracked header:

staged change	result
@date bump only	reverted to the HEAD value, file left untouched
real edit + stale date	stamped to today, copyright year extended
real edit + current date	no-op, exit 0

Note for anyone with a local checkout

The hand-written hook has to go for the framework shim to take the slot. One-time setup, already documented in CONTRIBUTING.md:

pip install pre-commit && pre-commit install

🤖 Generated with Claude Code