diffguard.yml

name: diffguard

on:
  pull_request:
    branches:
      - '**'
    types: [opened, synchronize, reopened]

concurrency:
  group: diffguard-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true

jobs:
  diffguard:
    name: Quality metrics
    if: (github.event.action != 'closed' || github.event.pull_request.merged == true)
    # Mutation testing is CPU-heavy (one `go test` invocation per mutant,
    # parallelized across cores). The 16-core runner matches the one used
    # by govulncheck and keeps PR turnaround under ~10 min on typical diffs.
    runs-on: ubuntu24.04-16core-64GB-600SSD-bor
    steps:
      - uses: actions/checkout@v5
        with:
          # diffguard needs the base branch history for `git diff` and
          # `git log --follow`, so fetch the full history (shallow clones
          # break merge-base resolution).
          fetch-depth: 0

      - uses: actions/setup-go@v6
        with:
          go-version-file: go.mod

      - uses: actions/cache@v4
        with:
          path: |
            ~/.cache/go-build
            ~/go/pkg/mod
          key: ${{ runner.os }}-diffguard-${{ hashFiles('**/go.sum') }}
          restore-keys: ${{ runner.os }}-diffguard-

      - name: Install diffguard
        run: go install github.com/0xPolygon/diffguard/cmd/diffguard@latest

      - name: Run diffguard
        id: diffguard
        shell: bash
        run: |
          # Keep diffguard's exit code when tee writes the step summary.
          set -o pipefail
          diffguard \
            --base origin/${{ github.base_ref }} \
            --complexity-threshold 15 \
            --complexity-delta-tolerance 5 \
            --function-size-threshold 80 \
            --function-size-delta-tolerance 15 \
            --file-size-threshold 800 \
            --file-size-delta-tolerance-pct 10 \
            --file-size-delta-tolerance-floor 20 \
            --tier1-threshold 80 \
            --tier2-threshold 60 \
            --mutation-sample-rate 20 \
            --test-timeout 5m \
            --output text \
            --fail-on error \
            . | tee "$GITHUB_STEP_SUMMARY"

      - name: Upload JSON report
        # Run even on failure so the survivor list is available for
        # triage. Skip mutation here to keep the second run cheap — the
        # text report above already contains the full mutation results.
        if: always()
        run: |
          diffguard \
            --base origin/${{ github.base_ref }} \
            --skip-mutation \
            --output json \
            --fail-on none \
            . > diffguard-report.json

      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: diffguard-report
          path: diffguard-report.json
          retention-days: 14