attempt-release.yml

name: Attempt release
on:
  # We want to release from the master branch.
  # Assuming that the actual work is done in branches, triggering the workflow
  # on pushes will ensure that every merged branch can potentially create a new
  # release
  push:
    branches: ["master"]
    tags: ["v*"]

jobs:
  create-version-tag:
    runs-on: ubuntu-latest
    environment:
      # These two are needed by the publish to pypi action
      # https://github.com/marketplace/actions/pypi-publish
      name: pypi
      url: https://pypi.org/p/semv
    permissions:
      contents: write  # needed for pushing tags or creating releases
      id-token: write  # needed for publish to pypi action
    steps:
      - uses: actions/checkout@v3
        with:
          # IMPORTANT: semv will look at our commit history
          # we therefore need to fetch all commits, which is done here by
          # setting fetch-depth to 0. See here for more details on the checkout action:
          # https://github.com/actions/checkout
          fetch-depth: 0

      - name: Setup python 3.8
        uses: actions/setup-python@v4
        with:
          # Why python3.8? It's the earliest python version that we support
          python-version: "3.8"

      - name: Install dependencies
        run: |
          pip install --upgrade pip
          pip install tox
          pip install -e .

      - name: Setup git and list existing tags
        run: |
          git config user.name "ci"
          git config user.email "ci"
          git config --global init.defaultBranch master
          git tag

      - name: Run tests
        # This could in principle be skipped if we were strict about only
        # merging branches that pass all tests. Ensures that accidental merge
        # conflicts don't break released package
        run: tox

      - name: Print version
        # This is the key step. By setting an id, we can read the output in later steps
        id: print-version
        # We only want to run this step if we are on a pushed commit -- it will
        # give an exit status of 1 if we are already on a version tag.
        if: startsWith(github.ref, 'refs/heads/')
        # In order to be able to read the output in later steps, we need to
        # write something that looks like a variable definitionn to the
        # environment variable GITHUB_OUTPUT
        run: echo "semv-out=$(semv)" >> $GITHUB_OUTPUT
        # NOTE: This step doesn't check the statuscode of semv (non-zero if no new version)

      - name: Create changelog
        run: |
          semv --changelog > ${{ github.workspace }}-CHANGELOG.md
          cat ${{ github.workspace }}-CHANGELOG.md

      - uses: thejeff77/action-push-tag@v1.0.0
        # Only run this step if this is a pushed commit and not a tag
        if: startsWith(github.ref, 'refs/heads/')
        with:
          # Here we refer to the variable that we just wrote the the GITHUB_OUTPUT variable
          tag: ${{ steps.print-version.outputs.semv-out }}
          # NOTE: This step will fail if semv-out is empty (i.e. there was no
          # new version) and thus all following steps won't run either.

      - name: Set output
        id: set_output
        # NOTE: We can unconditionally set should_publish=true here, because we
        # wouldn't even reach this point if one of the previous points had
        # failed.
        run: echo "set-output name=should_publish::true"

      - name: Setup git and list existing tags
        run: |
          git config user.name "ci"
          git config user.email "ci"
          git tag
          echo $${{ steps.set_output.outputs.should_publish }}

      # The following steps should be more or less standard python package publishing
      # Feel free to omit the github release.
      - name: Create github release
        uses: softprops/action-gh-release@v1
        if: ${{ steps.set_output.outputs.should_publish }} == 'true'
        with:
          tag_name: ${{ steps.print-version.outputs.semv-out }}
          body_path: ${{ github.workspace }}-CHANGELOG.md
          generate_release_notes: false   # do not generate release notes, we generated them with semv

      - name: Build package
        if: ${{ steps.set_output.outputs.should_publish }} == 'true'
        run: tox -e build

      - name: Publish to pypi
        if: ${{ steps.set_output.outputs.should_publish }} == 'true'
        uses: pypa/gh-action-pypi-publish@release/v1