Go Refactoring Workflow

A refactor changes structure, never behavior. The definition of done is mechanical: same tests pass before and after every step, and every step is small enough to revert alone.

1. The Loop

1. Baseline: go build ./... && go test ./... must be green before touching anything. If tests are missing around the target code, write characterization tests FIRST — they pin current behavior, even if that behavior looks wrong.
2. One transformation from the catalog below.
3. Verify: build + tests + go vet ./....
4. Commit. Never mix a refactor commit with a behavior change — reviewers can skim a refactor: commit; they must scrutinize a mixed one.
5. Repeat.