Build: Config Linter — Milestone 3

Your linter works when everything goes right. This milestone makes it survive everything going wrong — and puts it under test, where it stays forever.

The assignment

1. Wrap every file error with its filename:

   fmt.Errorf("lint %s: %w", path, err)
   

   An unreadable file must not crash the run — lint the rest, report the failure at the end, and keep going.

2. Table-driven tests for both rules in rules_test.go — the exact pattern from this module's lessons. At minimum: a clean input, a violating input, and an edge case per rule (e.g. image: nginx — no tag at all — for latest-tag).

3. Add a third rule, test-first. Pick one from the project's rules table (missing-labels is a good line-based candidate). Write its failing test before its code.

Done when

• go test ./... passes.
• Running against a directory containing one unreadable file (chmod 000 bad.yaml) still lints the others and reports the error without crashing.

Commit. From this milestone on, a passing test suite is the definition of done — for the linter and for every challenge in the rest of this course.

Where this ends up: Config Linter project page. After the next module, all of it is your job.