github_actions_branch.yml

name: github-actions branch

on: 
  pull_request:
    paths-ignore:
      - '**.md'

jobs:
  build:
    runs-on: ubuntu-20.04
    steps:
      - uses: actions/checkout@v2
      - name: Create tag
        uses: actions/github-script@v4
        with:
          script: |
            const fs = require('fs');

            const version = fs.readFileSync('./.version').toString().trim();

            const responseTags = await github.repos.listTags({
              owner: context.repo.owner,
              repo: context.repo.repo,
              per_page: 100,
            })

            const tags = responseTags.data.map(tag => tag.name);
            const existingTags = tags.filter(tag => tag == version);

            if (existingTags.length) {
              core.setFailed(`Tag ${version} already exists. Ensure you increment the version within the .version file`);
              return;
            }

            const alphaVersion = `${version}-alpha.${context.issue.number}.`;
            const usedAlphaNumbers = tags.filter(tag => tag.startsWith(alphaVersion)).map(tag => parseInt(tag.replace(alphaVersion, ''), 10)).sort();
            const newVersion = usedAlphaNumbers.length ? (usedAlphaNumbers[usedAlphaNumbers.length - 1] + 1) : 1;

            const response = await github.git.createRef({
              owner: context.repo.owner,
              repo: context.repo.repo,
              ref: `refs/tags/${alphaVersion}${newVersion}`,
              sha: context.sha
            })

            console.log(`Created tag: ${alphaVersion}${newVersion}`);