go-ci-gofmt-enforcement

Answer

Root cause: gofmt -l prints the paths of unformatted files but always exits 0 (verified: exit 0 with unformatted files present, exit 2 only on parse errors). The lint job either skipped gofmt entirely or ran it without failing on its output, so 26 files rotted with CI green.

Fix — three commits:

1. Style-only backlog commit. Run gofmt -w once and commit the whitespace/indentation fixes with no logic changes:

gofmt -w .                 # fix all 26 rotted files
git diff -w --stat         # MUST be empty → proves style-only
git add -A && git commit -m "style: gofmt -w over all packages (style-only)"

Push and confirm existing CI still passes before proceeding.

2. Enforcement commit — add a dedicated Check gofmt step to the lint job (.github/workflows/lint.yml), placed before the other lint steps so it fails fast:

name: lint

on:
  push:
    branches: [main]
  pull_request:

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-go@v5
        with:
          go-version: "1.22"

      - name: Check gofmt
        run: |
          unformatted="$(gofmt -l .)"
          if [ -n "$unformatted" ]; then
            echo "The following files are not gofmt-formatted:"
            echo "$unformatted"
            exit 1
          fi
          echo "All Go files are gofmt-formatted."

      - name: Run lints
        run: go vet ./...

The step fails on any output, which is the key: gofmt -l . alone cannot gate the build. This catches formatting drift on every push/PR, so the 150-tick decay can never recur. (Optional hardening: append go run golang.org/x/tools/cmd/goimports -l . for import grouping.)

3. Land enforcement as its own commit so CI history shows the style commit passing before the gate exists.