fuzz.yml

name: Fuzz test
on:
  pull_request:
jobs:
  find-tests:
    name: Find fuzz tests
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}
    steps:
      - uses: actions/checkout@v4
      - name: Find fuzz tests
        id: set-matrix
        run: |
          TEST_FILES=$(find . -name '*_test.go' -not -path './vendor/*')

          RESULTS=()

          for FILE in $TEST_FILES; do
            FUZZ_FUNC=$(grep -E 'func Fuzz\w*' $FILE | sed 's/func //' | sed 's/(.*$//')
            if [ -z "$FUZZ_FUNC" ]; then
              continue
            fi

            PACKAGE_PATH=$(dirname ${FILE#./})
            RESULTS+=("{\"package\":\"$PACKAGE_PATH\",\"function\":\"$FUZZ_FUNC\"}")

            echo "Found $PACKAGE_PATH :: $FUZZ_FUNC"
          done

          NUM_RESULTS=${#RESULTS[@]}
          INCLUDE_STRING=""
          for (( i=0; i<$NUM_RESULTS; i++ )); do
            INCLUDE_STRING+="${RESULTS[$i]}"

            if [[ $i -lt $(($NUM_RESULTS-1)) ]]; then
              INCLUDE_STRING+=","
            fi
          done

          echo 'matrix={"include": ['$INCLUDE_STRING']}' >> $GITHUB_OUTPUT

  fuzz:
    name: "${{ matrix.package }} :: ${{ matrix.function }}"
    runs-on: ubuntu-latest
    if: needs.find-tests.outputs.matrix != ''
    needs: [find-tests]
    strategy:
      fail-fast: false # Allow other jobs in the matrix to run even if a single one fails.
      matrix: ${{fromJson(needs.find-tests.outputs.matrix)}}
    steps:
      - uses: actions/checkout@v4

      - name: Set up Go 1.22
        uses: actions/setup-go@v5
        with:
          go-version: "1.22"
          cache: false

      - name: Find cache location
        run:
          echo "FUZZ_CACHE=$(go env GOCACHE)/fuzz" >> $GITHUB_ENV

      - name: Restore corpus
        uses: actions/cache@v4
        with:
          path: ${{ env.FUZZ_CACHE }}
          key: fuzz-${{ matrix.package }}-${{ matrix.function }}-${{ github.sha }}
          restore-keys: |
            fuzz-${{ matrix.package }}-${{ matrix.function }}-
          save-always: true

      - name: Fuzz
        run: |
          cd "${{ matrix.package }}"
          go test -fuzz="${{ matrix.function }}\$" -run="${{ matrix.function }}\$" -fuzztime=5s .

      # Fuzzing may have failed because of an existing bug, or it may have
      # found a new one and written a new corpus entry in testdata/ relative to
      # the package.
      #
      # If that file was written, we should save it as an artifact and then
      # create an issue.

      - name: Check for new corpus entry
        id: new-entry
        if: ${{ failure() }}
        run: |
          UNTRACKED=$(git ls-files . --exclude-standard --others)
          if [ -z "$UNTRACKED" ]; then
            exit 0
          fi
          echo "Found new corpus entry: $UNTRACKED"
          echo "entry=$UNTRACKED" >> $GITHUB_OUTPUT

      - name: Upload corpus entry
        if: ${{ failure() && steps.new-entry.outputs.entry != '' }}
        uses: actions/upload-artifact@v4
        with:
          name: failed-test
          path: ${{ steps.new-entry.outputs.entry }}