diffscope.yml

name: DiffScope Review
on:
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review, review_requested]

permissions:
  contents: read
  pull-requests: write

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

jobs:
  review:
    runs-on: ubuntu-latest
    if: github.event.pull_request.head.repo.full_name == github.repository && !github.event.pull_request.draft
    steps:
      - uses: actions/checkout@v5
        with:
          fetch-depth: 0
          ref: ${{ github.event.pull_request.head.sha }}

      - uses: actions/setup-node@v5
        with:
          node-version: 24
          cache: npm
          cache-dependency-path: web/package-lock.json

      - uses: dtolnay/rust-toolchain@1.88.0
      - uses: Swatinem/rust-cache@v2

      - name: Build frontend
        working-directory: web
        run: |
          npm ci
          npm run build

      - name: Build current DiffScope binary
        run: cargo build --release

      - name: Get PR diff
        run: |
          git fetch origin ${{ github.base_ref }} --depth=1
          git diff origin/${{ github.base_ref }}...HEAD > pr.diff

      - name: Select review provider
        id: provider
        env:
          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
          OPENROUTER_API_KEY: ${{ secrets.OPENROUTER_API_KEY }}
          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
        run: |
          if [ -n "${ANTHROPIC_API_KEY}" ]; then
            {
              echo "configured=true"
              echo "model=anthropic/claude-opus-4.5"
              echo "adapter=anthropic"
            } >> "$GITHUB_OUTPUT"
          elif [ -n "${OPENROUTER_API_KEY}" ]; then
            {
              echo "configured=true"
              echo "model=anthropic/claude-opus-4.5"
              echo "adapter=openrouter"
            } >> "$GITHUB_OUTPUT"
          elif [ -n "${OPENAI_API_KEY}" ]; then
            {
              echo "configured=true"
              echo "model=gpt-4o"
              echo "adapter=openai"
            } >> "$GITHUB_OUTPUT"
          else
            echo "configured=false" >> "$GITHUB_OUTPUT"
            echo "::notice::DiffScope review skipped; no ANTHROPIC_API_KEY, OPENROUTER_API_KEY, or OPENAI_API_KEY secret is configured"
          fi

      - name: Run DiffScope from this branch
        if: steps.provider.outputs.configured == 'true'
        env:
          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
          OPENROUTER_API_KEY: ${{ secrets.OPENROUTER_API_KEY }}
          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
        run: |
          ./target/release/diffscope \
            --model "${{ steps.provider.outputs.model }}" \
            --adapter "${{ steps.provider.outputs.adapter }}" \
            --output-format json \
            review --diff pr.diff --output comments.json

      - name: Upload review artifact
        if: always() && steps.provider.outputs.configured == 'true'
        uses: actions/upload-artifact@v4
        with:
          retention-days: 14
          name: diffscope-review-${{ github.event.pull_request.number }}
          path: comments.json
          if-no-files-found: ignore

      - name: Post comments
        if: steps.provider.outputs.configured == 'true'
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            if (!fs.existsSync('comments.json')) {
              core.notice('DiffScope did not produce comments.json');
              return;
            }
            const comments = JSON.parse(fs.readFileSync('comments.json', 'utf8'));
            const headSha = context.payload.pull_request.head.sha;
            const fallback = [];

            for (const comment of comments) {
              if (!comment.file_path || !comment.line_number || comment.line_number < 1) {
                continue;
              }
              const body = [
                `**${comment.severity}**: ${comment.content}`,
                comment.suggestion ? `\nSuggestion: ${comment.suggestion}` : ''
              ].join('');
              try {
                await github.rest.pulls.createReviewComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  pull_number: context.issue.number,
                  body,
                  commit_id: headSha,
                  path: comment.file_path,
                  line: comment.line_number,
                  side: "RIGHT"
                });
              } catch (error) {
                fallback.push(`- **${comment.severity}** ${comment.file_path}:${comment.line_number} ${comment.content}`);
              }
            }

            if (fallback.length > 0) {
              const body = [
                "Some review comments could not be placed inline and are listed below:",
                "",
                ...fallback.slice(0, 100)
              ].join("\n");
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body
              });
            }