test-without-fix.yml

# When a PR contains both test changes and source changes,
# this workflow runs the changed tests WITHOUT the source fix
# to verify that the tests actually reproduce the bug.
# - Tests FAILING without the fix = expected (confirms the test catches the bug)
# - Tests PASSING without the fix = warning (the test might not verify the bugfix)

name: Verify Test Reproduction

on:
  pull_request:

permissions:
  contents: read
  pull-requests: write

jobs:
  test-without-fix:
    runs-on: ubuntu-22.04
    timeout-minutes: 30
    steps:
      - uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - name: Check for changed test and source files
        id: check-changes
        run: |
          BASE_SHA="${{ github.event.pull_request.base.sha }}"
          HEAD_SHA="${{ github.event.pull_request.head.sha }}"
          MERGE_BASE=$(git merge-base "$BASE_SHA" "$HEAD_SHA")

          # Get changed test files (only *.test.ts files)
          CHANGED_TESTS=$(git diff --name-only "$MERGE_BASE" "$HEAD_SHA" -- 'test/' | grep '\.test\.ts$' || true)
          # Get changed source files
          CHANGED_SRC=$(git diff --name-only "$MERGE_BASE" "$HEAD_SHA" -- 'src/')

          if [ -z "$CHANGED_TESTS" ]; then
            echo "No test files changed, skipping"
            echo "should_run=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          if [ -z "$CHANGED_SRC" ]; then
            echo "No source files changed (test-only PR), skipping"
            echo "should_run=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          echo "should_run=true" >> "$GITHUB_OUTPUT"
          echo "Changed test files:"
          echo "$CHANGED_TESTS"
          echo ""
          echo "Changed source files:"
          echo "$CHANGED_SRC"

      - name: Set node version
        if: steps.check-changes.outputs.should_run == 'true'
        uses: actions/setup-node@v6
        with:
          node-version-file: ".nvmrc"

      - name: Reuse npm cache folder
        if: steps.check-changes.outputs.should_run == 'true'
        uses: actions/cache@v5
        env:
          cache-name: cache-node-modules
        with:
          path: |
            ~/.npm
            ./node_modules
          key: ${{ runner.os }}-npm-test-without-fix-x1-${{ hashFiles('**/package.json') }}
          restore-keys: |
            ${{ runner.os }}-npm-test-without-fix-x1-

      - name: Apply test changes to base branch code
        if: steps.check-changes.outputs.should_run == 'true'
        id: apply-patch
        run: |
          BASE_SHA="${{ github.event.pull_request.base.sha }}"
          HEAD_SHA="${{ github.event.pull_request.head.sha }}"
          MERGE_BASE=$(git merge-base "$BASE_SHA" "$HEAD_SHA")

          # Save the test directory changes as a patch
          git diff "$MERGE_BASE" "$HEAD_SHA" -- test/ > /tmp/test-changes.patch

          if [ ! -s /tmp/test-changes.patch ]; then
            echo "Empty patch, nothing to apply"
            exit 0
          fi

          # Checkout the merge base (code state before this PR)
          git checkout "$MERGE_BASE"

          # Apply only the test changes on top of the unfixed code
          git apply /tmp/test-changes.patch

      - name: Install dependencies
        if: steps.check-changes.outputs.should_run == 'true'
        run: npm install || (sleep 15 && npm install) || (sleep 15 && npm install)

      - name: Build
        if: steps.check-changes.outputs.should_run == 'true'
        id: build
        continue-on-error: true
        run: npm run build 2>&1 | tee /tmp/build-output.txt

      - name: Run tests (expect failure)
        if: steps.check-changes.outputs.should_run == 'true' && steps.build.outcome == 'success'
        id: run-tests
        continue-on-error: true
        run: npm run test:fast:memory 2>&1 | tee /tmp/test-output.txt

      - name: Evaluate results
        if: steps.check-changes.outputs.should_run == 'true'
        id: evaluate
        run: |
          echo "== Test-Without-Fix Results =="
          echo ""
          if [ "${{ steps.build.outcome }}" == "failure" ]; then
            echo "✅ Build FAILED without the source changes."
            echo "This confirms the test requires the source changes from this PR."
            COMMENT_ICON="✅"
            COMMENT_TITLE="Build FAILED without the source changes (expected)"
            COMMENT_BODY="This confirms the source changes in this PR are required for the build to succeed."
            OUTPUT_FILE="/tmp/build-output.txt"
          elif [ "${{ steps.run-tests.outcome }}" == "failure" ]; then
            echo "✅ Tests FAILED without the fix."
            echo "This confirms the test correctly reproduces the bug."
            COMMENT_ICON="✅"
            COMMENT_TITLE="Tests FAILED without the fix (expected)"
            COMMENT_BODY="This confirms the changed tests correctly reproduce the bug that the source changes fix."
            OUTPUT_FILE="/tmp/test-output.txt"
          else
            echo "⚠️ Tests PASSED without the fix."
            echo "The changed tests do not fail without the source changes from this PR."
            echo "Please inspect whether the test changes actually test the bug that the source changes fix."
            COMMENT_ICON="⚠️"
            COMMENT_TITLE="Tests PASSED without the fix (unexpected)"
            COMMENT_BODY="The changed tests do not fail without the source changes from this PR. Please inspect whether the test changes actually test the bug that the source changes fix."
            OUTPUT_FILE="/tmp/test-output.txt"
          fi
          echo ""
          echo "This workflow is informational only. Inspect the output above to verify the test reproduces the bug."

          # Write comment header to file
          {
            printf '## %s Verify Test Reproduction: %s\n\n' "$COMMENT_ICON" "$COMMENT_TITLE"
            printf '%s\n\n' "$COMMENT_BODY"
            printf '%s\n\n' '_This workflow runs the changed tests **without** the source fix to verify they reproduce the bug._'
          } > /tmp/pr-comment.md

          # Append truncated output if available
          if [ -f "$OUTPUT_FILE" ]; then
            TOTAL_LINES=$(wc -l < "$OUTPUT_FILE")
            printf '<details>\n<summary>Show output</summary>\n\n```\n' >> /tmp/pr-comment.md
            if [ "$TOTAL_LINES" -gt 200 ]; then
              printf '...(truncated, showing last 200 of %s lines)\n' "$TOTAL_LINES" >> /tmp/pr-comment.md
              tail -200 "$OUTPUT_FILE" >> /tmp/pr-comment.md
            else
              cat "$OUTPUT_FILE" >> /tmp/pr-comment.md
            fi
            printf '\n```\n\n</details>\n\n' >> /tmp/pr-comment.md
          fi

          echo "[View full workflow run](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})" >> /tmp/pr-comment.md

          exit 0

      - name: Post or update PR comment
        if: steps.check-changes.outputs.should_run == 'true'
        uses: actions/github-script@v8
        with:
          script: |
            const fs = require('fs');
            const commentBody = fs.readFileSync('/tmp/pr-comment.md', 'utf8');
            const marker = '<!-- test-without-fix-bot -->';
            const body = marker + '\n' + commentBody;

            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });

            const existing = comments.find(c => c.body.includes(marker));

            if (existing) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existing.id,
                body,
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body,
              });
            }