version-check.yml

name: Verify version

on:
  pull_request:
    branches:
      - master

permissions:
  contents: read

jobs:
  version-check:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Extract versions
        id: versions
        run: |
          set -euo pipefail
          extract() {
            grep -E '^[[:space:]]*version[[:space:]]*=' "$1" | head -1 \
              | sed -E 's/.*"([^"]+)".*/\1/'
          }

          PR_VERSION=$(extract build.gradle.kts)
          if [ -z "$PR_VERSION" ]; then
            echo "::error file=build.gradle.kts::Could not extract version from build.gradle.kts on PR branch."
            exit 1
          fi

          BASE_FILE=$(git show "origin/${{ github.base_ref }}:build.gradle.kts")
          BASE_VERSION=$(echo "$BASE_FILE" | grep -E '^[[:space:]]*version[[:space:]]*=' | head -1 \
            | sed -E 's/.*"([^"]+)".*/\1/')
          if [ -z "$BASE_VERSION" ]; then
            echo "::error::Could not extract version from build.gradle.kts on origin/${{ github.base_ref }}."
            exit 1
          fi

          echo "pr=$PR_VERSION"   >> "$GITHUB_OUTPUT"
          echo "base=$BASE_VERSION" >> "$GITHUB_OUTPUT"
          echo "PR:   $PR_VERSION"
          echo "Base: $BASE_VERSION"

      - name: Reject 'dev' in version
        run: |
          PR='${{ steps.versions.outputs.pr }}'
          if echo "$PR" | grep -qi 'dev'; then
            echo "::error file=build.gradle.kts::Version '$PR' contains 'dev' — must not be merged."
            exit 1
          fi

      - name: Verify version is not lower
        run: |
          set -euo pipefail
          PR='${{ steps.versions.outputs.pr }}'
          BASE='${{ steps.versions.outputs.base }}'

          if [ "$PR" = "$BASE" ]; then
            echo "Version unchanged ($BASE) — OK."
            exit 0
          fi

          LOWER=$(printf '%s\n%s\n' "$PR" "$BASE" | sort -V | head -1)
          if [ "$LOWER" != "$BASE" ]; then
            echo "::error file=build.gradle.kts::PR version ($PR) is lower than base version ($BASE). Version must only go up."
            exit 1
          fi

          echo "PR version $PR > base version $BASE — OK."