check-minimum-revision.yaml

name: "Check Minimum Revision"

on:
  workflow_call:
    inputs:
      GIT_SHA:
        required: true
        type: string
  workflow_dispatch:
    inputs:
      GIT_SHA:
        required: true
        type: string

env:
  GIT_SHA: ${{ inputs.GIT_SHA }}
  MINIMUM_REVISION: ${{ secrets.MINIMUM_REVISION }}

jobs:
  check-minimum-revision:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          ref: ${{ env.GIT_SHA }}
          fetch-depth: 1000
      - name: Check merge base is new enough
        id: check-merge-base
        run: |
          set -ex

          if [ -z "$MINIMUM_REVISION" ]; then
            echo "Skipping check"
            exit 0
          fi

          git fetch origin main

          set +e
          git merge-base \
            --is-ancestor "$MINIMUM_REVISION" "${{ env.GIT_SHA }}"
          FAILED=$?
          set -e

          echo "FAIL_MERGE_BASE=${FAILED}" >> $GITHUB_OUTPUT
          MERGE_BASE="$(git merge-base origin/main ${{ env.GIT_SHA }})"

          if [[ $FAILED == 1 ]]; then
            echo "Your merge base $MERGE_BASE is too old" | tee fail-merge-base.txt
            echo "Please rebase on or past $MINIMUM_REVISION" | tee -a fail-merge-base.txt
          fi