mutants-pr.yml

name: Find PR mutants
on:
  pull_request:
  merge_group:

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

permissions:
  contents: read

env:
  RUST_BACKTRACE: 1
  MUTANTS_ARGS: --no-shuffle --in-place --profile mutants -- --all-targets -- -Zunstable-options --fail-fast

jobs:
  mutants:
    name: Find mutants
    runs-on: ubuntu-24.04
    steps:
      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          fetch-depth: 0
          persist-credentials: false

      - id: nss-version
        uses: ./.github/actions/minimum-version
        with:
          directory: .
      - uses: mozilla/actions/nss@27cbe8fb5d338c2861b787e5de10410559065db1 # v1.1.3
        with:
          minimum-version: ${{ steps.nss-version.outputs.minimum }}
          token: ${{ secrets.GITHUB_TOKEN }}

      - uses: mozilla/actions/rust@27cbe8fb5d338c2861b787e5de10410559065db1 # v1.1.3
        with:
          version: nightly
          tools: cargo-mutants
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Generate diff
        env:
          BASE_REF: ${{ github.base_ref || github.event.merge_group.base_ref }}
        run: |
          # Strip refs/heads/ prefix if present (merge_group events use full ref).
          BASE_REF="${BASE_REF#refs/heads/}"
          git diff "origin/${BASE_REF}.." > pr.diff

      - name: Find mutants
        run: |
          # shellcheck disable=SC2086
          # Exit codes: 0=success, 1=build/test failure (fail workflow),
          # 2=missed, 3=timeout, 4=unviable (suppress, report in summary).
          (cargo mutants --in-diff pr.diff $MUTANTS_ARGS 2>&1 \
            || { ec=$?; [ $ec -ge 2 ] && [ $ec -le 4 ] && exit 0; exit $ec; }) | tee results.txt

      - name: Post step summary
        if: always()
        run: |
          {
            echo "### Incremental Mutants"
            echo "Mutants found in files changed by this PR."
            echo "See https://mutants.rs/using-results.html for more information."
            echo '```'
            sed 's/\x1b\[[0-9;]*[mGKHF]//g' results.txt || true
            echo '```'
          } > "$GITHUB_STEP_SUMMARY"

      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        if: always()
        with:
          name: mutants.out
          path: mutants.out