name: Version bump

# Runs only on pull requests: it compares cadence.py's __version__ on the head
# branch against the base branch and fails if the version was not increased.
#
# Kept as a separate workflow rather than a job-level `if:` inside ci.yml:
# forgejo-runner does not reliably skip a job on `if:` and reports the skipped
# job as a failure on push events.

on:
  pull_request:

jobs:
  version-bump:
    runs-on: docker
    steps:
      - name: Checkout
        # v4 runs on node20 (v5+ require node24); full history so the base
        # branch is reachable for the comparison.
        uses: https://data.forgejo.org/actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Require a version bump
        shell: bash
        run: |
          set -euo pipefail

          # `github.base_ref` is the GitHub-compatible alias and is understood
          # by Forgejo; `forgejo.base_ref` is the canonical spelling.
          BASE="${{ github.base_ref }}"
          if [ -z "$BASE" ]; then
            echo "No base ref; skipping version check."
            exit 0
          fi

          git fetch --no-tags origin "$BASE"

          if [ ! -f cadence.py ]; then
            echo "::error::cadence.py is missing from the change."
            exit 1
          fi

          NEW=$(sed -n 's/^__version__[[:space:]]*=[[:space:]]*"\([^"]*\)".*/\1/p' cadence.py | head -n1)
          if [ -z "$NEW" ]; then
            echo "::error::No __version__ found in cadence.py"
            exit 1
          fi

          # The script may be introduced by this very PR: if it does not exist
          # on the base branch there is no previous version to bump from.
          if ! git cat-file -e "FETCH_HEAD:cadence.py" 2>/dev/null; then
            echo "cadence.py is new to '$BASE' (no base version); version check passes."
            exit 0
          fi

          OLD=$(git show "FETCH_HEAD:cadence.py" | sed -n 's/^__version__[[:space:]]*=[[:space:]]*"\([^"]*\)".*/\1/p' | head -n1)
          echo "base __version__: ${OLD:-<none>}  head __version__: $NEW"
          if [ -z "$OLD" ]; then
            echo "Could not read a base version; skipping."
            exit 0
          fi

          # Require NEW to be strictly greater than OLD (version sort).
          GREATER=$(printf '%s\n%s\n' "$OLD" "$NEW" | sort -V | tail -n1)
          if [ "$NEW" = "$GREATER" ] && [ "$OLD" != "$NEW" ]; then
            echo "Version bumped: $OLD -> $NEW"
          else
            echo "::error::cadence.py __version__ must be bumped above $OLD (currently $NEW)."
            exit 1
          fi