jscpd.yml

name: Check for Duplicated Code

on:
  pull_request:
    branches:
      - master

permissions:
  contents: read

jobs:
  check-duplication:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout code
      uses: actions/checkout@v6
      with:
        fetch-depth: 0

    - name: Set up Node.js
      uses: actions/setup-node@v6
      with:
        node-version: '20'

    - name: Install jscpd
      run: npm install -g jscpd

    - name: Create jscpd config file
      run: |
        echo '{
          "threshold": 20,
          "minTokens": 100,
          "reporters": [
            "json"
          ],
          "output": "./",
          "pattern": "**/*.js",
          "ignore": ["**/*spec.js"]
        }' > .jscpd.json

    - name: Run jscpd on entire codebase
      run: jscpd

    - name: Fetch base branch for comparison
      run: |
        git fetch origin refs/heads/${{ github.base_ref }}

    - name: Get changed files
      run: |
        git diff --name-only FETCH_HEAD...HEAD > changed_files.txt
        cat changed_files.txt

    - name: List generated files (debug)
      run: ls -l

    - name: Upload unfiltered jscpd report
      if: always()
      uses: actions/upload-artifact@v7
      with:
        name: unfiltered-jscpd-report
        path: ./jscpd-report.json

    - name: Filter jscpd report for changed files
      run: |
        if [ ! -f ./jscpd-report.json ]; then
          echo "jscpd-report.json not found"
          exit 1
        fi
        echo "Filtering jscpd report for changed files..."
        CHANGED_FILES=$(jq -R -s -c 'split("\n")[:-1]' changed_files.txt)
        echo "Changed files: $CHANGED_FILES"
        jq --argjson changed_files "$CHANGED_FILES" '
          .duplicates | map(select(
            (.firstFile?.name as $fname | $changed_files | any(. == $fname)) or
            (.secondFile?.name as $sname | $changed_files | any(. == $sname))
          ))
        ' ./jscpd-report.json > filtered-jscpd-report.json
        cat filtered-jscpd-report.json

    - name: Check if filtered jscpd report exists
      id: check_filtered_report
      run: |
        if [ $(wc -l < ./filtered-jscpd-report.json) -gt 1 ]; then
          echo "filtered_report_exists=true" >> $GITHUB_ENV
        else
          echo "filtered_report_exists=false" >> $GITHUB_ENV
        fi

    - name: Upload filtered jscpd report
      if: env.filtered_report_exists == 'true'
      uses: actions/upload-artifact@v7
      with:
        name: filtered-jscpd-report
        path: ./filtered-jscpd-report.json

    - name: Generate PR comment
      if: env.filtered_report_exists == 'true'
      uses: actions/github-script@v8
      with:
        script: |
          const fs = require('fs');
          const filteredReport = JSON.parse(fs.readFileSync('filtered-jscpd-report.json', 'utf8'));
          let comment = "Whoa there, partner! 🌵🤠 We wrangled some duplicated code in your PR:\n\n";
          function link(dup) {
             return `https://github.com/${{ github.repository }}/blob/${{ github.event.pull_request.head.sha }}/${dup.name}#L${dup.start + 1}-L${dup.end - 1}`
          }
          filteredReport.forEach(duplication => {
            const firstFile = duplication.firstFile;
            const secondFile = duplication.secondFile;
            const lines = duplication.lines;
            comment += `- [\`${firstFile.name}\`](${link(firstFile)}) has ${lines} duplicated lines with [\`${secondFile.name}\`](${link(secondFile)})\n`;
          });
          comment += "\nReducing code duplication by importing common functions from a library not only makes our code cleaner but also easier to maintain. Please move the common code from both files into a library and import it in each. We hate that we have to mention this, however, commits designed to hide from this utility by renaming variables or reordering an object are poor conduct. We will not look upon them kindly! Keep up the great work! 🚀";
          fs.writeFileSync('${{ runner.temp }}/comment.json', JSON.stringify({
            issue_number: context.issue.number,
            body: comment
          }))

    - name: Upload comment data
      if: env.filtered_report_exists == 'true'
      uses: actions/upload-artifact@v7
      with:
        name: comment
        path: ${{ runner.temp }}/comment.json

    - name: Fail if duplications are found
      if: env.filtered_report_exists == 'true'
      run: |
        echo "Duplications found, failing the check."
        exit 1